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The ecology and successional trends of tundra plant communities in the low arctic subalpine zone of the… Lambert, John David Hamilton 1968

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THE ECOLOGY AND SUCCESSIO'NAL TRENDS OF TUNDRA PLANT COMMUNITIES IN THE LOW ARCTIC SUBALPINE ZONE OF THE RICHARDSON AND BRITISH MOUNTAINS OF THE CANADIAN WESTERN ARCTIC, by JOHN DAVID HAMILTON LAMBERT B.Sc. University of Vermont, 1960 M.Sc. McGill University, 1964 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department, of Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA January, 1968 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o lumbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g of t h i s t h e s i s f o r s c h o l a r l y p urposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n -t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada Date ABSTRACT P r i o r to 1963 no previous vegetation studies had been undertaken i n t h i s region o f the Low A r c t i c S u b a l p i n e / F o o t h i l l Zone of the Canadian Western A r c t i c , although s e v e r a l s t u d i e s had been completed i n s i m i l a r regions i n A r c t i c Alaska. This study was i n i t i a t e d i n 1965 to ob t a i n q u a n t i t a t i v e and q u a l i t a t i v e data on v e g e t a t i o n and environmental r e l a t i o n s h i p s , i n c l u d i n g s o i l data f o r c h a r a c t e r i -z a t i o n of Low A r c t i c . S u b a l p i n e / F o o t h i l l Zone s o i l s . With these b a s i c data i t was considered p o s s i b l e to analyze, i n t e g r a t e and i n t e r p r e t community and s o i l r e l a t i o n s h i p s and to propose a usable c l a s s i f i c a t i o n system f o r the recognizable ecosystematic u n i t s i n t h i s p o r t i o n o f the zone. I n i t i a l c r i t e r i a f o r s e l e c t i n g communities were based on u n i f o r m i t y and d i s c r e t e n e s s . Vegetation i n each community was s t u d i e d by the s i n g l e p l o t method I I employing p h y t o s o c i o l o g i c a l techniques of the Zu r i c h - M o n t p e l l i e r School as modified by K r a j i n a (1933). Data on environmental c o n d i t i o n s c o l l e c t e d f o r each of 166 communities i n c l u d e d degree of s l o p e , p r o f i l e , p a t t e r n of topography, exposure, a l t i t u d e and wind i n f l u e n c e . C o e f f i c i e n t s o f s i m i l a r i t y between communities were computed using the 2W formula x 100, where A i s the sum of a l l measures (a.bundance and A + B presence) f o r one community, B i s the sum of a l l measures f o r another community, and W i s the sum of the lower values f o r each species which the two communities have i n common. To determine the degree of a f f i n i t y and r e l a t i v e h i a t u s points between groups of communities c l u s t e r a n a l y s i s using the weighted p a i r - group method was employed. A two-dimensional dendrogram i l l u s t r a t e d the i n d i v i d u a l p l o t s and succeeding c l u s t e r s . One s o i l p i t was dug i n every analyzed p l o t to e i t h e r permafrost, water t a b l coarse i c e s h a t t e r e d parent m a t e r i a l or bedrock. A t o t a l of 498 s o i l samples f o r l a b o r a t o r y a n a l y s i s were c o l l e c t e d from a l l r e c o g n i z a b l e horizons. Chemical analyses were undertaken to determine organic matter content, t o t a l n i t r o g e n , carbon/nitrogen r a t i o , absorbed phosphorus, exchangeable calcium, magnesium, potassium and sodium, c a t i o n exchange c a p a c i t y pH. Because s o i l p r o f i l e s showed considerable v a r i a t i o n the r e s u l t s o f the chemical analyses were averaged f o r the organic, organic - mineral and mineral h o r i z o n s . On the b a s i s of s i m i l a r i t y of species composition s i x orders, e i g h t a l l i a n c e s , fourteen a s s o c i a t i o n s , ten s u b a s s o c i a t i o n s and t h i r t e e n v a r i a t i o n s were d i s -t i n g u i s h e d . The order B e t u l e t a l i a glandulosae dominated the two study areas, o c c u r r i n g on moderately to w e l l drained mesic to x e r i c slopes. Community develop-ment w i t h i n t h i s order appeared s t a b l e under the present topographic and c l i m a t i c c o n d i t i o n s . The V a c c i n i o - Betuletum glandulosae c l o s e l y approximated the c l i m a t i c climax i n mesic h a b i t a t s . Successional concepts on upper slopes appeared of l i m i t e d value because communities tended to be d i s c r e t e . Communities dominant on the lower slopes and i n the wetlands were c h a r a c t e r i z e d by a narrow a c t i v e , poor to impeded drainage c o n d i t i o n s and more i n t e n s i v e f r o s t a c t i o n . C l a s s i f i c a t i o n was more d i f f i c u l t i n such areas because communities appeared to be l e s s s t a b l e . Successional development i n such areas w i t h permanent seepage was toward the Betulo - Eriphoretum v a g i n a t i . Snow bed h a b i t a t s were c h a r a c t e r i z e d by the order P e t a s i t e t a l i a f r i g i d i i , which was d i s t i n g u i s h e d f o r the f i r s t time i n North America, and i n c l u d e d the p r e v i o u s l y undescribed Salicetum chamissonis. Sharp environmental gradients between chionophilous and chionophobous communities sug-gested t h a t the c l i m a t e had undergone no s i g n i f i c a n t change i n the recent past. S i m i l a r i t i e s between the Low A r c t i c S u b a l p i n e / F o o t h i l l Zone communities and those i n other a r c t i c r e g i o n s , e s p e c i a l l y Scandinavia, were shown to occur. Twelve s o i l types were d i s t i n g u i s h e d . In a l l but two cases each s o i l type was a s s o c i a t e d with a p a r t i c u l a r p l a n t a s s o c i a t i o n . A form of p o d z o l i z a t i o n p r e v i o u s l y described i n A r c t i c Alaska was recognized i n the A r c t i c Brown s o i l s . G l e i z a t i o n , however, appeared to be the major s o i l forming process i n t h i s r e g ion of the zone. I t was a s s o c i a t e d w i t h both chionophobous*and chionophilous v e g e t a t i o n . In the former, i t was favoured by poor drainage, a shallow a c t i v e l a y e r and i n t e n s i v e f r o s t a c t i o n ; i n the l a t t e r , i t appeared r e l a t e d to m a t e r i a l s deposited on the snow that were l a t e r i n c o r p o r a t e d i n t o the s o i l f o l l o w i n g snow melt. The high organic content and c a t i o n exchange c a p a c i t y and the low a c i d i t y and base s a t u r a t i o n were concluded to be important chemical c h a r a c t e r i s t i c s of these s o i l s . F i n a l r e s u l t s using c l a s s i f i c a t i o n methods showed that the present p o s i t i o n cf the communities i n t h i s r e gion of the Low A r c t i c S u b a l p i n e / F o o t h i l l Zone were r e l a t e d to e l e v a t i o n , exposure, s o i l moisture, thickness of the a c t i v e l a y e r , d u r a t i o n of snow cover, c o n g e l i t u r b a t i o n and topography. i v Table of Contents Pages A b s t r a c t i i Table of Contents v L i s t of Tables ., • v i i i L i s t of Figures x Acknowledgment • X 1 1 I n t r o d u c t i o n 1 2 D e s c r i p t i o n of the Area 4 Environment 4 Topography 4 Geology 8 Climate 9 S o i l s 15 Permafrost - The e f f e c t s on v e g e t a t i o n and s o i l 22 3 Mi c r o c l i m a t e A n a l y s i s and Synthesis 27 4 Vegetation 33 Methods of a n a l y s i s 33 Problems i n v e g e t a t i o n s y n t h e s i s 34 Vegetation s y n t h e s i s - C l u s t e r a n a l y s i s .' 36 Results of c l u s t e r a n a l y s i s 39 5 D e s c r i p t i o n of Vegetation Units 41 Chionophobous ( T e r r e s t r i a l ) p l a n t communities 41 Salicetum phlebophyllae 41 Lupino - Dryadetum * a l a s k e n s i s 44 lupin o - dryadetosum * a l a s k e n s i s (depauperatum) 44 dryado - salicetosum r e t i c u l a t a e - glaucae 46 Betulo - Ledetum decumbentis 49 betulo - ledetosum decumbentis 50 casslopeetosum tetragonae 52 V a c c i n i o - Betuletum glandulosae 55 v a c c i n i o - betuletosum glandulosae (fruticulosum) ... 56 v a c c i n i o - betuletosum glandulosae (fruticosum) 58 Betulo - Chamaemoretum 61 be t u l o - chamaemoretosum. . . 61 alnetosum c r i s p a e 62 Betulo - Eriophoretum v a g i n a t i 63 eriophoretosum v a g i n a t i 64 salicetosum r e t i c u l a t a e 67 Aquatic p l a n t communities 69 Arctophiletum f u l v a e 69 S e m i - T e r r e s t r i a l p l a n t communities 71 Eriophoretum a n g u s t i f o l i i 72 eriophoretosum a n g u s t i f o l i i . . . . 72 salicetosum pulchrae 75 v Car i c e turn a q u a t i l i s . . 75 caricosum a q u a t i l i s 75 salicosum a r b u t i f o l i a e 76 Eriophoretum scheuchzeri 77 Caricetum r a r i f l o r a e 78 Chionophilous p l a n t communities 79 Salicetum pseudopolaris 80 Salicetum chamissonis . 81 salicosum chamissonis 82 equisetosum a r v e n s i s 84 festucosum a l t a i c a e 85 caricosum montanensis 85 arctagrostidosum l a t i f o l i a e . ' 86 salicosum pulchrae 86 Salicetum pulchrae 87 salicosum pulchrae 87 betulosum glandulosae 90 salicosum r i c h a r d s o n i i 91 7 C l a s s i f i c a t i o n and D e s c r i p t i o n of the S o i l s 100 Sub-Aquatic S o i l s 101 Sub-Aquatic not peat forming 101 O l i g o t r o p h i c G y t t j a 101 Sub-Aquatic peat forming 101 Carex Fen 102 Low-Centered Polygon Mire 103 Brown Moss 103 Peat Moss 104 S e m i - T e r r e s t r i a l (Groundwater) S o i l s 105 S e m i - T e r r e s t r i a l Raw S o i l s 105 Snow Basin Rutmark 105 Anmoor-like S o i l s 106 Snow Basin Anmoor 106 Tundra Anmoor 108 S e m i - T e r r e s t r i a l Peat S o i l s 109 Tundra Moss 109 Peat Anmoor 112 T e r r e s t r i a l Land S o i l s ^ 113 T e r r e s t r i a l Raw S o i l s 113 A r c t i c Rawmark 114 Ran k e r - l i k e S o i l s 115 Tundra Ranker 115 Rendzina S o i l s . . 116 A r c t i c Brown shallow phase 116 Brown Earths 117 A r c t i c Brown normal phase 118 S o i l - V e g e t a t i o n R e l a t i o n s h i p s 121. 8 . D e s c r i p t i o n of .Higher Units of C l a s s i f i c a t i o n 123 9 Tundra Mudf lows 127 10 Vegetation, Environmental and Successional R e l a t i o n s h i p s 129 11 Summary and Conclusions 150 12 B i b l i o g r a p h y . . . 156 v i Appendix I Annoted Species l i s t Appendix I I Average d a i l y c l i weather s t a t i o n s Appendix I I I Explanatory notes synthesis t a b l e s t i c data f o r a l l nine f o r v e g e t a t i o n and environment LIST.OF TABLES Table 1: Summary of average temperatures and r e l a t i v e humidity data f o r m i c r o c l i m a t i c s t a t i o n s at Canoe Lake, J u l y and August 1966. 2(a): Summary of ve g e t a t i o n data f o r Salicetum phlebophyllae. (b): Summary of environmental data f o r Salicetum phlebophyllae. 3(a): Summary of vege t a t i o n data f o r Lupino - Dryadetum * a l a s k e n s i s . (b): Summary of environmental data f o r Lupino - Dryadetum * a l a s k e n s i s 4(a): Summary of vege t a t i o n data f o r Betulo - Ledetum decumbentis. (b): Summary of environmental data f o r Betulo - Ledetum decumbentis. 5(a): Summary of v e g e t a t i o n data f o r V a c c i n i o - Betuletum glandulosae. (b): Summary of environmental data f o r V a c c i n i o - Betuletum glandulosae. 6( a ) : Summary of v e g e t a t i o n data f o r Betulo - Chamaemoretum (b): Summary of environmental data f o r Betulo - Chamaemoretum 7(a): Summary of ve g e t a t i o n data f o r Betulo - Eriophoretum v a g i n a t i '• (b) : Summary of environmental data f o r Betulo - Eriophoretum v a g i n a t i . 8(a ) : Summary of ve g e t a t i o n data f o r Arctophiletum f u l v a e . (b): Summary of environmental data f o r Arctophiletum f u l v a e . 9(a) : Summary of v e g e t a t i o n data f o r Eriophoretum a n g u s t i f o l i i . (b): Summary of environmental data f o r Eriophoretum a n g u s t i f o l i i . 10(a): Summary of ve g e t a t i o n data f o r Caricetum a q u a t i l i s . (b): Summary of environmental data f o r Caricetum a q u a t i l i s . 11(a): Summary of v e g e t a t i o n data f o r Eriophoretum scheuchzeri. (b): Summary of environmental data f o r Eriophoretum scheuchzeri. 12(a): Summary of v e g e t a t i o n data f o r Caricetum r a r i f l o r a e . (b): Summary of environmental data f o r Caricetum r a r i f l o r a e . 13(a): Summary of ve g e t a t i o n data f o r Salicetum pseudopolaris. (b): Summary of environmental data f o r Salicetum pseudopolaris. 14(a): Summary of ve g e t a t i o n data f o r Salicetum chamissonis. (b): Summary of environmental data f o r Salicetum chamissonis. 15(a): Summary of v e g e t a t i o n data f o r Salicetum pulchrae. (b): Summary of environmental data f o r Salicetum pulchrae. 16: Summary of s o i l chemical analyses of the organ i c , organic-mineral and mineral horizons. 17: P r o v i s i o n a l s o i l c l a s s i f i c a t i o n f o r the Low A r c t i c Subalpine/ F o o t h i l l Zone. v i i i LIST. OF TABLES (CONTINUED) C l a s s i f i c a t i o n of p l a n t communities of the Low A r c t i c Subalpine/ F o o t h i l l Zone on the b a s i s o f c h a r a c t e r i s t i c species combinations C l a s s i f i c a t i o n of p l a n t communities o f the Low A r c t i c Subalpine/ F o o t h i l l Zone ( v a r i a t i o n , sub-association and a s s o c i a t i o n ) . C l a s s i f i c a t i o n o f p l a n t communities of the Low A r c t i c Subalpine/ F o o t h i l l Zone ( a s s o c i a t i o n , a l l i a n c e and o r d e r ) . LIST OF FIGURES Figure 1: The major physiographic zones of the A r c t i c Slope of A l a s k a , Yukon T e r r i t o r y and Northwest T e r r i t o r i e s . 2: General view of the Canoe Lake area l o o k i n g northwest. 3: General view of the Trout Lake area lo o k i n g n o r t h . 4 ( a ) : S t r a t i g r a p h i c c r o s s - s e c t i o n of the area bordering Canoe Lake (E-W). 4(b): S t r a t i g r a p h i c c r o s s - s e c t i o n of the area bordering Trout Lake (N-S). 5: C l i m a t i c data f o r the A r c t i c Slope. Average monthly temperatures p l o t t e d and p r e c i p i t a t i o n at Barrow, A l a s k a , Umiat, Shingle P o i n t , Yukon and Inuvik, Northwest T e r r i t o r i e s . 6: Late snow bed h a b i t a t , Canoe Lake. 7: L o c a t i o n of nine weather s t a t i o n s e s t a b l i s h e d i n the Canoe Lake area and o p e r a t i o n a l during J u l y and August, 1966. 8: Weather s t a t i o n No. 4 i n a Cassiope tetragona dominated s i t e s , Canoe Lake 1966. 9: Dendrogram of p l o t s i m i l a r i t i e s i n d i c a t i n g major a s s o c i a t i o n s and s u b a s s o c i a t i o n s . 10: S a l i x p h l e b o p h y l l a dominated depression on exposed r i d g e , west s i d e o f Canoe Lake, showing evidence of f r o s t heaving. 11: Exposed r i d g e south of Trout Lake dominated by Dryas o c t o p e t a l a and S a l i x p h l e b o p h y l l a . 12: Southwest f a c i n g upper s l o p e , Canoe Lake, dominated by Dryas o c t o p e t a l a and Lupinus a r c t i c u s . 13: Betula glandulosa and Ledum decumbens dominated sl o p e , Canoe Lake, w i t h evidence of f r o s t heaving and downs lope movement of surface m a t e r i a l s . 14: S l i g h t l y chionophilous depression h a b i t a t on east f a c i n g s l o p e , Canoe Lake, dominated by Cassiope tetragona. 15: East f a c i n g dip slope east of Canoe Lake dominated by p r o s t r a t e B e t u l a glandulosa and Vaccinium uliginosum with Carex lugens on r a i s e d mounds. 16: Depression h a b i t a t on lower east f a c i n g s l o p e , Canoe Lake, domi-nated by shrub ( B 2 ) Betula glandulosa and. Vaccinium uliginosum. 17: Eriophorum vaginatum tussocks with.' Sphagnum lenense dominating i n the wet depressions, present on lower slopes. 18: Northwest f a c i n g upper slope dominated by Eriophorum vaginatum and . bordered by exposed Dryas o c t o p e t a l a dominated slope. x LIST OF FIGURES (CONTINUED) Lake shore v e g e t a t i o n , Canoe Lake. The emergent aquatic A r c t o p h i l a f u l v a bordered by :Eriophorum scheuchzeri. Drainage pathway on lower slope, Canoe Lake, dominated by Eriophorum a r i g u s t i f o l i u m . Sedge meadow i n v i r t u a l l y o b l i t e r a t e d a q uatic h a b i t a t , Trout Lake, dominated by Carex a q u a t i l i s . Very l a t e snow bed h a b i t a t , Canoe Lake, dominated by S a l i x  p seudopolaris. Amphitheatre, Canoe Lake, w i t h snow s t i l l present i n e a r l y August. Late snow bed h a b i t a t dominated by S a l i x chamissonis w i t h S i b b a l d i a procumbens and A r n i c a l e s s i n g i i . S l i g h t l y chionophilous Salicetum pulchrae i n d i c a t i n g dense C l a y e r . Snow Basin Rutmark s o i l a s s o c i a t e d w i t h Salicetum pseudopolaris. Snow Basin Anmoor s o i l a s s o c i a t e d with Salicetum chamissonis. Tundra Moss s o i l a s s o c i a t e d with Betulo - Chamaemoretum. A r c t i c Brown normal phase s o i l a s s o c i a t e d w i t h V a c c i n i o - Betuletum glandulosae ( f r u t i c u l o s u m ) . Massive tundra mudflow scar on slope south of Canoe Lake. I s o l a t e d i s l a n d s of v e g e t a t i o n j u s t below tundra mudflow s c a r . E a r l y stages of r e v e g e t a t i o n on tundra mudflow. Terminal area of tundra mudflow. D i s t r i b u t i o n of p l a n t communities on east f a c i n g s l o p e , Canoe Lake, i n d i c a t i n g approximate permafrost l e v e l and snow depth. D i s t r i b u t i o n o f s e m i - t e r r e s t r i a l communities i n area of impeded drainage i n d i c a t i n g approximate permafrost depth and snow depth. D i s t r i b u t i o n of chionophilous and s l i g h t l y chionophilous communities i n d i c a t i n g approximate permafrost depth and snow depth. x i ACKNOWLEDGEMENTS I t i s a p r i v i l e g e to express my a p p r e c i a t i o n to Dr. V. J . K r a j i n a f o r guidance, encouragement and a s s i s t a n c e throughout the study, both i n the f i e l d and l a t e r i n the l a b o r a t o r y . I am indebted to Dr. W. B. S c h o f i e l d who checked a l l my bryophyte i d e n t i f i c a t i o n s . His w i l l i n g n e s s to a s s i s t i n a l l stages of the study i s g r a t e f u l l y acknowledged. Other members of the F a c u l t y at the U n i v e r s i t y of B r i t i s h Columbia, i n c l u d i n g Dr. J . Ross Mackay and Dr. T. M. C. T a y l o r , were always w i l l i n g to a s s i s t and discuss the study. For t h i s , I am very g r a t e f u l . In a d d i t i o n , the a s s i s t a n c e of Dr. A. E. P o r s i l d , N a t i o n a l Museum, and Dr. J . W. Thomson, U n i v e r s i t y o f Wisconsin, i n determining c e r t a i n d i f f i c u l t v a s c u l a r p l a n t s and l i c h e n s i s asknowledged. Without the a s s i s t a n c e of Mr. S. Borden, Program A n a l y s t , U n i v e r s i t y of B r i t i s h Columbia, the adaption of the computer program used i n the i n i t i a l vege-t a t i o n analyses would not have been p o s s i b l e , h i s help i s very g r a t e f u l l y ac-knowledged. The s o i l analyses have been preformed by Mr. B. von S p i n d l e r , Department of S o i l Science, U n i v e r s i t y o f B r i t i s h Columbia, and my thanks are g r a t e f u l l y given. Many i n d i v i d u a l s rendered a s s i s t a n c e i n the f i e l d and w i t h t h e i r help much of the l o g i s t i c s a s s o c i a t e d w i t h a r c t i c f i e l d work were overcome. They i n c l u d e : Mr„ R. H i l l , Inuvik Research Laboratory, Mr. V. D. Hawley, Canadian W i l d l i f e S e r v i c e , I n u v i k , and Reindeer A i r S e r v i c e , Inuvik. S p e c i a l thanks are due to Mr. Douglas Morrison, who was my f i e l d . a s s i s t a n t i n 1965. The success of the f i r s t f i e l d season was, i n p a r t , a r e s u l t o f h i s enthusiasm. F i n a n c i a l a s s i s t a n c e toward meeting the cost o f the f i e l d work has been provided i n the form o f a research a s s i s t a n t s h i p from the President's Committee on A r c t i c and A l p i n e Research, U n i v e r s i t y of B r i t i s h Columbia, through Dr. V. J . K r a j i n a . A d d i t i o n a l f i n a n c i a l a s s i s t a n c e was provided from the N a t i o n a l Research C o u n c i l Grant T-92 of my a d v i s o r . The award of two U n i v e r s i t y Fellowships by the F a c u l t y of Graduate S t u d i e s , U n i v e r s i t y of B r i t i s h Columbia, made the completion of t h i s study p o s s i b l e . INTRODUCTION The a r c t i c tundra occupies a considerable p o r t i o n of Canada's c o n t i n e n t a l land mass north o f the t r e e l i n e . R e l a t i v e l y few s y n e c o l o g i c a l s t u d i e s have been undertaken i n t h i s vast region and not one i n the low a r c t i c subalpine or a l p i n e zones i n the northwestern regions o f the Northwest T e r r i t o r i e s and Yukon T e r r i t o r y . Many b o t a n i s t s , s c i e n t i f i c personnel and other v i s i t o r s to the north have c o l l e c t e d p l a n t s e x t e n s i v e l y so that our knowledge of a r c t i c f l o r i s t i c s i s cons i d e r a b l e . The ve g e t a t i o n i s a f f e c t e d by severe environments that have, over a prolonged p e r i o d of time, s e l e c t e d a r e l a t i v e l y small f l o r a t o l e r a n t o f these extreme c o n d i t i o n s . Temperature i s an important l i m i t i n g f a c t o r , having a profound e f f e c t on metabolic processes as they r e l a t e to pl a n t growth and development. Furthermore, the low summer temperatures r e s u l t i n i n t e n s i v e f r o s t a c t i o n or c o n g e l i t u r b a t i o n i n the t h i n a c t i v e l a y e r or up-per s o i l h o r i z o n s . Propagation i s retarded and r e s t r i c t e d p r i m a r i l y to veg-e t a t i v e reproduction. The a r c t i c f l o r a i n general i s circumpolar. Several s p e c i e s , however, have developed geographical subspecies or races, while the m a j o r i t y have broad ranges o f amplitude. Most a r c t i c b o t a n i s t s and phytogeographers consider the a r c t i c f l o r a to be very o l d (Hulten, 1937, P o r s i l d , 1951, and Love, 1962). During successive i c e advances i n the P l e i s t o c e n e the a r c t i c f l o r a i s con-s i d e r e d to have p e r s i s t e d i n u n g l a c i a t e d r e f u g i a . Each i n t e r g l a c i a l p e r i o d appears to.have been of s u f f i c i e n t d u r a t i o n t o ' a l l o w a complete r e d i s t r i b u t i o n o f the f l o r a . P o r s i l d (1951) d i v i d e d a r c t i c North America i n t o f o u r d i s t i n c t phytogeographical regions. They are: 1) A r c t i c p a r ts o f Alaska and Yukon; 2) A r c t i c p a r t s o f c o n t i n e n t a l Northwest T e r r i r o r i e s and Ungava; 3) A r c t i c A r c h i p e l a g o ; 4) Greenland. The a r c t i c Alaska and Yukon region possesses the most v a r i e d f l o r a (over 600 s p e c i e s ) . This region i s l a r g e l y u n g l a c i a t e d and r i c h i n endemic and d i s j u n c t s p e c ies. In western a r c t i c North America l i t t l e a t t e n t i o n has been given to ve g e t a t i o n and environmental r e l a t i o n s h i p s . How-, ever, these r e l a t i o n s h i p s have been discussed i n general terms as they r e l a t e to a x c t i c tundra (Benninghoff, 1952, 1963 and B r i t t o n , 1957) and a r c t i c and a l p i n e tundras ( C h u r c h i l l and Hanson, 1958, and B l i s s , 1962). With the ex-cepti o n of q u a n t i t a t i v e s t u d i e s by Hanson (1953) i n northwestern A l a s k a , C h u r c h i l l (1955) i n the Umiat region of Al a s k a and Spetzman (1959) on the a r c t i c slope o f A l a s k a , l i t t l e a t t e n t i o n has been p a i d to t h i s unique area. A comparison has been made by B l i s s (1962) of p l a n t development i n micro-environment on the northern a r c t i c slope of Alaska and the Mount Washington (al p i n e ) tundra. Elsewhere, the l i t e r a t u r e i n c l u d e s only phytogeographical notes i n r e l a t i o n to l o c a l f l o r a with no e c o l o g i c a l i n f o r m a t i o n . Information on s o i l s has been gathered e x t e n s i v e l y over the past seven-teen years i n northern Alaska. This work has been c a r r i e d out by Tedrow and hi s students (1955-62) from Rutger's U n i v e i ' s i t y , New Jersey. C l i m a t i c data have increased w i t h the opening of the D i s t a n t E a r l y Warning (D.E.W.) l i n e s t a t i o n s along the a r c t i c coast. M i c r o c l i m a t i c data are l i m i t e d , the major study being by Conover (1960) on the macro- and microc l i m a t o l o g y of the a r c t i c slope of Alaska. With the exception of comparative c l i m a t i c data from the D.E.W. l i n e s t a t i o n s along the coast no other environmental i n f o r m a t i o n i s a v a i l a b l e f o r the u n g l a c i a t e d low a r c t i c subalpine and a l p i n e regions of the northern Yukon and adjacent Northwest T e r r i t o r i e s west o f the Mackenzie Delt a . P r i o r to 1963 when K r a j i n a and colleagues analyzed s e v e r a l communities from the Richardson Mountains i n the v i c i n i t y of Canoe Lake no previous q u a n t i t a t i v e or q u a l i t a t i v e s t u d i e s had been undertaken i n t h i s r e g i o n . This study was i n i t i a t e d i n 1965 to ob t a i n d e t a i l e d i n f o r m a t i o n on vegetation and environmental r e l a t i o n s h i p s as they p e r t a i n e d to t h i s low a r c t i c Subalpine/ F o o t h i l l Zone. S u i t a b l e areas f o r study were numerous, however; t h e i r a c c e s s i -b i l i t y v/as l i m i t e d by the lack of lakes. Only two were large enough to 3 accommodate a i r c r a f t , . t h e y were Canoe Lake, Richardson Mountains, NWT, and Trout Lake,. B r i t i s h Mountains, Yukon. The f i e l d season i n 1965 extended from e a r l y June to l a t e August. Only three weeks during J u l y were spent at Trout Lake, the remainder of the time being spent at Canoe Lake. In 1966, between l a t e June and l a t e August, i n -v e s t i g a t i o n s were c a r r i e d out only i n the Canoe Lake area. The p r i n c i p a l o b j e c t i v e s were to o b t a i n q u a n t i t a t i v e and q u a l i t a t i v e data f o r a d e s c r i p t i o n o f the i d e n t i f i a b l e v e g e t a t i o n u n i t s . At. the same time, s i m i l a r type data were obtained f o r c h a r a c t e r i z a t i o n of the s o i l s . With these b a s i c data i t i s p o s s i b l e to analyze, i n t e g r a t e and i n t e r p r e t community and s o i l r e l a t i o n s h i p s and to propose a c l a s s i f i c a t i o n f o r the reco g n i z a b l e eco-systematic u n i t s i n t h i s r e gion of the S u b a l p i n e / F o o t h i l l Zone. This d i s s e r t a t i o n f o l l o w s the coer.otic approach i n c l a s s i f i c a t i o n i n which a s s o c i a t i o n s are ab s t r a c t e d from l a r g e samples by grouping i n d i v i d u a l communities together on the b a s i s o f s i m i l a r i t y . I t i s b e l i e v e d that the present study c o n t r i b u t e s new in f o r m a t i o n concerning low a r c t i c subalpine p l a n t communities and t h e i r environmental r e l a t i o n s h i p s as w e l l as pre s e n t i n g o r i g i n a l data on p r e v i o u s l y undescribed low a r c t i c , subalpine chionophilous meadows. 4 AREA 'DESCRIPTION Environment The A r c t i c Slope of western North America extends from the c r e s t s of the Brooks, B r i t i s h , and Richardson Mountains northward to the A r c t i c Ocean and from j u s t west of the Mackenzie D e l t a to Cape Lisburne, Alaska. I t extends more than 750 miles east-west and from 150-200 miles.north-south. The A r c t i c Slope (Figure 1) i s d i v i d e d i n t o three physiographic regions (Payne and ot h e r s , 1951 and Bostock, 1961): the c o a s t a l p l a i n , the f o o t h i l l s or A r c t i c P l a t e a u (Subalpine) and the northern slopes of the mountains ( A l p i n e ) . Each region d i f f e r s i n topography, geology, c l i m a t e , s o i l and v e g e t a t i o n . The S u b a l p i n e / F o o t h i l l Zone i n northern Canada i s 10-110 miles i n width, being narrow i n f r o n t of the B r i t i s h and Richardson Mountains and extending i n -land between these two ranges toward the Old Crow P l a i n i n c e n t r a l northern Yukon f o r a consi d e r a b l e d i s t a n c e . The Subalpine and A l p i n e Zones have been above sea. l e v e l s i n c e E a r l y Cretaceous and are considered to have been l a r g e l y f r e e of g l a c i a l i c e . The topography i s v a r i a b l e c o n s i s t i n g of w e l l to moderately drained slopes as w e l l as p o o r l y drained wetlands. Permafrost i s continuous except under the few l a r g e r , deeper l a k e s . Many la r g e r i v e r s t r a n s e c t the mountain ranges while the l o c a l topography i s d i s s e c t e d by a myriad of drainage pathways. Topography ' The t e r r a i n i n the Canoe Lake area i s very i r r e g u l a r . The range i n eleva-t i o n i s from 1050-2400 f t . Two major cuestas dominate the area, one on each s i d e of the lake. The l a k e , three miles long and h a l f a mile wide, l i e s i n a shale b a s i n formed by the erosion o f the shale. The cuestas are asymmetrical and have a north-south s t r i k e w i t h scarps f a c i n g due west. The backslope of the eastern cuesta i s low and continuous, dropping from 1500 f t to 800 f t i n approximately two and a h a l f m i l e s . The scarp face drops 500 f t to lake l e v e l i n l e s s than a quarter of a m i l e . On the east f a c i n g slope (scarp face) of the 164 I 1 6 0 ° -1 152° —\ 144 " T 136° Herschsl Island EXPLANATION STUDY AREAS 2 Foothills Mountoln»(N slop«) Figure 1. The major p h y s i o g r a p h i c a l zones of the A r c t i c Slope of Alaska, Yukon T e r r i t o r y and Northwest T e r r i t o r i e s (Payne and others, 1951 and Bostock, 1961). O O O Crq CP 5 western cuesta felscnmecr^ i s exposed f o r about two and a h a l f miles at 1500 f t and only three quarters of a mile from the lake . (Figure 2) Above the f e l s e n -meer the slope r i s e s to 2100 f t , where exposed bedrock i s dominant. This cuesta beginning j u s t south of the lake extends northward f o r approximately f i v e m i l e s . Opposite the south end of the lake on the western cuesta at 1500 f t i s a prom-inent amphitheatre or draw with an e a s t e r l y exposure. Snow p e r s i s t s here f o r over eleven months o f the year. Figure 2. North end of Canoe Lake (1050 f t ) l o o k i n g northwest and r i s i n g to 2100 f t . The exposed parent rock and felsenmcer i s at approximately 1500 f t . Dark green areas on east f a c i n g slope i n d i c a t e shrub communities, on west f a c i n g slope i n d i c a t e drainage pathways with p r o s t r a t e shrub s p e c i e s . (Photo by Kraj i n a ) . On both slopes o f the cues Las the general topography i s hummocky and re-mains moist throughout the summer. On the scarp faces the increased slope r e s u l t s i n b e t t e r drainage and the t e r r a i n i s l e s s hummocky. She l t e r e d s i t e s 1. Exposed f r o s t broken loose rock 6 among the felsenmeer support a t h i c k carpet of v e g e t a t i o n . The major drainage channel south of the lake i s a creek i n t o which the surrounding slopes d r a i n . The creek cuts through the eastern cuesta and drains due east i n t o the Mackenzie D e l t a j u s t west of A k l a v i k . A short cuesta due south of the creek r i s e s to 1900 f t and has a rim p l a t e a u of i c e - s h a t t e r e d b l o c k s . Between t h i s cuesta and the western cuesta are three raised, rim plateaus that are separated by drainage pathways - probably e r o s i o n a l . The lowland between the south end of the lake and the creek i s very wet, a r e s u l t of poor drainage derived from a general accumulation of organic matter. In t h i s area i s what appears to be a c l o s e d system pingo. Low-centered polygons predominate around the pingo, with numerous drainage pathways e n c i r c l i n g them. Canoe Lake i s drained by a small creek at i t s north end. The outflow i s very slow and the surrounding v e g e t a t i o n i s c o n t i n u a l l y encroaching. Tundra mudflows are common i n the area. Previous mudflows i n d i f f e r e n t , stages of r e v e g e t a t i o n are evident a l l around the lake and on s e v e r a l steep slopes bordering the creek south of i t . These movements are a r e s u l t o f sur-face heaving during the autumn i n which the v e g e t a t i o n mat i s separated from the mineral s o i l . The f o l l o w i n g s p r i n g during the thaw the s a t u r a t e d s o i l flows downslope l e a v i n g i s l a n d s of v e g e t a t i o n s c a t t e r e d throughout the mudflow. The t e r r a i n around Trout Lake i s more r e g u l a r than that around Canoe Lake, however, at no time does i t approach the g e n t l y r o l l i n g c o n d i t i o n prevalent on the C o a s t a l P l a i n . The area' immediately east of Trout Lake i s bordered by the Babbage R i v e r . To the west and north P h i l i p Creek forms a n a t u r a l boundary. Both water courses d r a i n northward and have cut deeply i n t o the bedrock so t h a t t e r r a c e s and escarpments are conspicuous f e a t u r e s . The range i n e l e v a t i o n i n the study area i s from. 500 f t to 1600 f t . The dominant feature i s a very low d i p , Trout Lake i s i n the middle, surrounded by a myriad of drainage pathways. The t i l t e d bed, i t s e l f , i s very low and i n a l l p r o b a b i l i t y i s not a t r u e s t r i k e but an escarpment. South of Trout Lake 7 (at 600-7G0 f t ) arc t i l t e d beds that dip to the north. The beds at the east-ern end are low with low scarps w h i l e at the western end the scarps are higher and the slopes more pronounced. South of these low exposed beds i s a prominent cuesta r i s i n g to 1600 f t . Drainage on the dip of t h i s cuesta runs east-west, while on the low beds to the north the drainage i s to the north. (Figure 3). Figure 3. Trout Lake (600 f t ) l o o k i n g north. Babbage R i v e r i n the background. L i g h t green areas i n foreground are drainage pathways. Exposed E-W s t r i k e s may be recognized by lack of v e g e t a t i o n . (Photo by Lambert). The r e g u l a r i t y o f the topography i s r e l a t e d to the homogeneity of the bedrock. Several outcrops of black shale are exposed along the west bank of the Babbage R i v e r and at the south end of Trout Lake. The l a k e , i t s e l f , probably l i e s on a shale bed. Drainage from the scarp of the south cuesta re-s u l t s i n an almost c o n t i n u a l run of water during the summer. On the lower reaches of the scarp are what appear to be deposits from e r o s i o n a l r u n o f f . 8 The more elevated regions are dry with only a sparse cover of v e g e t a t i o n . The low east-west beds j u s t to the north are w e l l drained and the depressions between them, where snow accumulates, d r a i n r e l a t i v e l y e a r l y i n the summer. West of Trout Lake, below the escarpment, i s an extensive lowland where low-centered polygons predominate. The meandering stream that drains Trout Lake passes through t h i s area and drains i n t o P h i l i p Creek. The t e r r a c e face on the west bank of the Babbage Ri v e r has a slope of over 65° and i s unvegetated i n many areas. Several lakes i n the area are d r y i n g up and so provide v a l u a b l e s i t e s f o r t r a c i n g s u c c e s s i o n a l trends. T o p o g r a p h i c a l l y , the two study areas are d i s s i m i l a r , however, environmental c o n d i t i o n s appear to be s i m i l a r . The m a j o r i t y of the p l a n t community types are common to both, areas and, t h e r e f o r e , c r i t e r i a f o r c o n s i d e r i n g them as both part of the F o o t h i l l s r e g i o n . Geology^ Two cuestas, one on each s i d e of Canoe Lake, with a north-south s t r i k e and an east dip dominate the immediate area. (Figure 4a). They c o n s i s t of two sandstone beds with a t h i c k shale i n t e r v a l s e p a r a t i n g them. The western cuesta, exposed at 2050 f t , i s Upper J u r a s s i c , w h i le the eastern cuesta, at 1500 f t , i s Lower Cretaceous. On the lower reaches of the scarp of the western cuesta i s exposed Permian rock. The v e g e t a t i o n was not s t u d i e d at t h i s l e v e l . The sandstones are c l e a n , quartzose, f i n e to medium grained and medium bedded. The shales form the dip slopes of both cuestas. The shales are b l a c k , s o f t , carbonaceous and r i c h i n organic m a t e r i a l . The v e g e t a t i o n i n the area i s g e n e r a l l y confined to areas u n d e r l a i n by s h a l e , the tops of the ridges where the sandstones outcrop are s p a r s e l y covered. 1. The f o l l o w i n g g e o l o g i c a l d e s c r i p t i o n of the two study areas i s based on i n f o r m a t i o n s u p p l i e d by Mr. W.E. Mroszczak, Party C h i e f , Imperial O i l E n t e r p r i s e s , Inuvik, Northwest T e r r i t o r i e s , during the summer of 1966. to follow page 8 Figure 4 (a)&(b) S t r a t i g r a p h i c c r o s s - s e c t i o n s of major study areas. Information supplied by Mr.W.E.Mroszczak,Party Chief, Imperial O i l Enterprises,Inuvik,N.W.T.1966. 9 The topography i s governed by the d i f f e r e n c e s i n r e s i s t a n c e to erosion of the p r i n c i p a l rock types, the sandstones forming the r i d g e s , and the soft, shales forming the v a l l e y s between. This i s q u i t e general throughout the area., s i n c e these rock u n i t s outcrop i n t h i s p a r t of the Richardson Mountains. Ex-posed rock at the 1500 f t l e v e l on the western s i d e of Canoe Lake i s g e n e r a l l y l e v e l and can be r e l a t e d to the general warping that occurs when cuestas o r i g -i n a t e . Large sandstone boulders and felsenmeer s c a t t e r e d over t h i s slope are probably a r e s u l t o f exposure and excessive f r e e z i n g and thawing. At Trout Lake (Figure 4b) the geology resembles that at Canoe Lake, with Upper J u r a s s i c and Lower Cretaceous sandstones forming the ri d g e s and shale i n t e r v a l s forming the f l a t v a l l e y s between. The shale o v e r l i e s the Upper J u r a s s i c sandstone w i t h a g r a d a t i o n a l contact, i . e . there i s a zone of i n t e r -bedded shales and sandstones grading to a pure shale as found exposed at the south end of Trout Lake. This shale i s q u i t e hard, with some s i l t s i z e d m a t e r i a l , s p l i n t e r y , and with some s i l t s t o n e i n t e r b e d s . Organic content i s thought to be q u i t e high. The rocks i n t h i s area have been consid e r a b l y f o l d e d and metamorphosed to a s l i g h t l y higher degree than at. Canoe Lake. To the northwest of Trout Lake the ridges are formed by r e s i s t a n t , l i g h t grey M i s s i s s i p p i a n limestones. The v e g e t a t i o n on t h i s rock type, as w e l l as that on the Lower Cretaceous (to the n o r t h ) , was not s t u d i e d as both were i n -a c c e s s i b l e on f o o t . C1imat e C l i m a t i c data f o r the c o a s t a l regions o f a r c t i c North America have been continuous s i n c e the opening of the D i s t a n t E a r l y Warning (D.E.W.) l i n e i n 1957. : In the i n t e r i o r , c l i m a t i c data are very incomplete with records a v a i l -able only from Umiat, Alaska. I n western a r c t i c Canada no c l i m a t i c records are a v a i l a b l e . Records are a v a i l a b l e f o r A k l a v i k and Inuvik i n the Mackenzie D e l t a . Both these settlements are considered to be w i t h i n the s u b a r c t i c zone as they are 30 miles south of the t r e e l i n e (Mackay, 1963). At present, only the c l i m a t i c data from one D.E.W. l i n e s t a t i o n , Shingle P o i n t , can be used f o r comparison with Inuvik data and w i t h that c o l l e c t e d i n the f i e l d . This s t a t i o n i s 60 miles N.W. of Canoe Lake and 38 miles E.N.E. of Trout Lake. Throughout the a r c t i c slope the c l i m a t e i s severe, c h a r a c t e r i z e d by long c o l d w i n t ers and short cool summers with frequent cloud and fog cover ( B r i t t o n , 1957). The c o l d e s t month at Barrow and Umiat, A l a s k a , i s February; on the 29 year record the former i s -24 CF, the l a t t e r -18°F. At Shingle Point and Inuvik the c o l d e s t month i s January; at the former between 1960-1964 the average was -15.5°F, and at the l a t t e r between 1957-1964 i t was -21.9°F. (Figure 5). The warmest p e r i o d , when mean temperatures are above f r e e z i n g , i s from June to August. Temperatures have been recorded i n the high 70's and low 80's along the coast and i n the high 80's i n the i n t e r i o r . Temperatures r i s e r a p i d l y i n the s p r i n g and drop as r a p i d l y i n the autumn. This r i s e and f a l l i s more pronounced i n the i n t e r i o r where a c o n t i n e n t a l c l i m a t e e x i s t s . The growing season, or snow f r e e p e r i o d , not to be confused with the f r o s t f r e e p e r i o d , i s longer and warmer i n the f o o t h i l l s than at the coast. Growth c o n d i t i o n s are, t h e r e f o r e , considered more favourable i n the i n t e r i o r . The warmest month during the growing season i s J u l y f o l l o w e d by August and June. Frost f r e q u e n t l y occurs during the height of the growing season and can be accompanied by snow. Such periods are u s u a l l y of short d u r a t i o n and ap-pear to have l i t t l e e f f e c t on the v e g e t a t i o n . The f r o s t f r e e p e r i o d i n 1966 at Canoe Lake l a s t e d 37 days. During most of the growing season there i s a p o t e n t i a l 24 hour photoperiod, but t h i s i s not always a t t a i n e d due to periods of cloud cover, l o c a l fog and degree c a r d i n a l exposure of slope,- Prolonged 50 40 ^ ~ 32 - ~ 30 ZZZ3 - E c t— a> -* "1 20 ac u. a> a. a> s fe. 10 U J " O 0 -10 -20 January February March Apr i l May June July August September! October November December /Zr_-:: # \ \ — Uaiat \\N — •yv' Barro» _ Shingle Pt. \ V ^ * — - ^ N . ^'—'l^Qt'' Inuvik ' \ . ^ PRECIPITATION (inches) IMa t 0.34 0.17 0.17 0.87 0.14 0.61 0.40 1.74 0.31 0.43 0.28 0.27 PRECIPITATION (inches) Barrot 0.15 0.13 0.12 0.10 0.12 0.26 0.84 0.75 0.51 0.53 0.27 0.20 PRECIPITATION (inches) Shingle Point 0.25 0.07 0.06 0.26 0.20 0.98 1.83 1.28 0.54 1.50 0.28 0.07 PRECIPITATION (inches) 1nuvi k 0.94 0.56 0.53 0.85 0.51 0.86 1.81 1.17 0.70 1.46 0.77 0.74 Figure 5. Climatic data for the Arctic Slope. Average monthly temperature and precipitation at Barrow, Alaska (29 year record) and Shingle Point, Yukon (4 year record) on the coastal plain, at Umiat, Alaska (3 year record) in the foothills and Inuvik, N.WT. (8 year record) in the sub-arctic. U.S. Weather Bureau (Spetzman, 1959) and D.O.T.M.B., Canada. 11 periods of sunshine are i n f r e q u e n t . C l e a r days f o l l o w e d by n i g h t s w i t h heavy mist and cloud cover provide a maximum of h e a t i n g and consequent thaw-ing of the a c t i v e l a y e r ( B r i t t o n , 1957). D i u r n a l temperature extremes are c o n s i d e r a b l e , and are accentuated on a l l north and south, east and west slopes and help to e x p l a i n the d i v e r s i t y of p l a n t communities encountered. Of the various environmental f a c t o r s temperature i s the most important l i m i t i n g f a c -t o r w i t h regard to p l a n t growth and development i n the tundra. ( B l i s s , 1962). Wind i s an ever present environmental f a c t o r i n the a r c t i c tundra. A l -though wind speeds are reduced near the ground surface and w i t h i n clumps of tundra p l a n t s , the p r o s t r a t e c o n d i t i o n of much of the v e g e t a t i o n does allow i t t o be e f f i c i e n t i n reducing temperature. The r e d u c t i o n i n a i r and l e a f tem-perature w i l l upset the favourable temperature microclimate of the low a r c t i c v e g e t a t i o n (Warren Wilson, 1959) . P r i o r t o the complete disappearance of snow during the annual thaw, excessive t r a n s p i r a t i o n can take p l a c e i n the exposed branches of shrubs due to wind a c t i o n . A c o n d i t i o n of permanent w i l t i n g can then be reached before the lower p o r t i o n s have thawed and s t a r t e d to t r a n s l o c a t e water. A s i m i l a r c o n d i t i o n probably p r e v a i l s i n the autumn when an e a r l y freeze and snow f a l l are f o l l o w e d by strong winds and above f r e e z i n g temperatures. The p r e v a i l i n g wind at Trout Lake and Canoe Lake throughout the winter months i s from the northwest, while i n the summer i t i s from the west and north-west. During the summers of 1965 and 1966 there were many days from J u l y to mid-August when s o u t h e r l y winds were a l s o recorded during the " d a y l i g h t hours". In l a t e June and J u l y many prolonged periods were recorded during the 24 hour p e r i o d i n which there was no d i s c e r n a b l e a i r movement. This was a l s o the case i n v a l l e y s as w e l l as on r i d g e tops and tended to occur i n the l a t e afternoon. In l a t e August high winds are more common i n the Trout Lake area than at Canoe Lake, a r e s u l t of the more r e g u l a r topography and the c l o s e p r o x i m i t y of the A r c t i c Ocean. Annual p r e c i p i t a t i o n i s g e n e r a l l y low throughout the a r c t i c ; at Shingle 12 Point f o r the p e r i o d 1960-1964 being only 7.32 inches, at Inuvik f o r the p e r i o d 1957-1964, 10.57 inches. During the summer of 1966 c o n s i d e r a b l y more r a i n f e l l i n the Canoe Lake area than had f a l l e n the previous summer. In 1965 only two days of l i g h t r a i n was recorded; while i n 1966 between J u l y 18-29th over eight inches of r a i n water was c o l l e c t e d i n the canoe at the lake (admittedly not an i d e a l r a i n gauge, n e v e r t h e l e s s , a good i n d i c a t i o n of the amount of p r e c i p i t a t i o n ) . Within the same p e r i o d 1.28 inches were recorded at Inuvik and 0.61 inches at Shingle Point (D.O.T.M.B., 1966). During the summers of 1965 and 1966 a phenomenum observed on most c l e a r days at Canoe Lake was the b u i l d up of cumulus clouds that appeared each mid-day to the west, over the Yukon T e r r i t o r y . These clouds are a r e s u l t of warm a i r r i s i n g and c o o l i n g over the Old Crow F l a t s . G e n e r a l l y , these clouds move east and tend to d i s s i p a t e before reaching Canoe Lake. In 1966, these a i r masses f a i l e d to break up u n t i l they reached the Mackenzie D e l t a , conse-quently p r e c i p i t a t i o n f e l l on many days. At times 100% r e l a t i v e humidity was maintained f o r a week at a time. Recent s t u d i e s have shown that i n general p r e c i p i t a t i o n exceeds evapo-t r a n s p i r a t i o n by small amounts during the growing season (Mather and Thornth-waite, 1956). This i s borne out by a comparative study of these r e l a t i o n s h i p s at s t a t i o n s along an environmental gradient extending from Point Barrow to the Meade R i v e r , a d i s t a n c e of 67 miles to the southwest and 28 miles from the coast, Clebsch (1957) demonstrated i n c r e a s i n g values of average d a i l y evapora-t i o n , t r a n s p i r a t i o n and p r e c i p i t a t i o n . At a l l s t a t i o n s p r e c i p i t a t i o n exceeded evaporation. Although the a c t u a l s n o w f a l l i s l i g h t snow cover i s an important e c o l o g i c a l f a c t o r on the tundra. Snow provides a p r o t e c t i v e cover f o r v e g e t a t i o n and i s a source of abundant water during the annual thaw. On i r r e g u l a r topography, snow accumulation i n large d r i f t s i s favoured by strong winds. P o r s i l d (1957) recognized two types of p l a n t h a b i t a t r e l a t e d to snow cover, both of considerable prominence on the a r c t i c landscape. The snowbed i s defined as a s i t e where large masses of snow accumulate each winter due to i r r e g u l a r topography. (Figure G). This type of snow cover h a b i t a t i s more prevalent i n a r c t i c -a l p i n e regions. P l a n t s growing i n t h i s type of s i t e have to complete t h e i r v e g e t a t i v e l i f e c y c l e i n i e s s than a month and so are adapted to a short grow-in g season. In the two study areas discussed here snowbed s i t e s were gen-e r a l l y on s l o p i n g creek banks or o l d lake banks with a s o u t h e r l y or e a s t e r l y exposure. In unfavourable seasons the snowcovcr w i l l not disappear completely so that p l a n t s that emerge from i t have i n s u f f i c i e n t time t o flower or pro-duce f r u i t s . Figure 6. Late snow bed h a b i t a t i n the Canoe Lake area bordered on both sides by shrub (B_j S a l i x p u l c h r a . Photograph taken i n e a r l y August s h o r t l y a f t e r snow melt. "(Photo by K r a j i n a ) . The snowpatch h a b i t a t i s a t r u l y a r c t i c phenomenum. I t u s u a l l y develops i n shallow depressions where, owing to p r e v a i l i n g winds, a snowdrift forms each w i n t e r , a f f o r d i n g p r o t e c t i o n f o r the v e g e t a t i o n beneath i t . Snow melt i these depressions i s completed s h o r t l y a f t e r that of the surrounding landscap so that i n the summer such s i t e s are f a i r l y dry. V a s c u l a r p l a n t s a s s o c i a t e d with t h i s h a b i t a t are predominantly woody, such as ground b i r c h and heath, with mosses. In the study area, snowpatch communities were present at eleva-t i o n s above 1500 f t at Canoe Lake and above 700 f t at Trout Lake. A e o l i a n d e p o s i t i o n of f i n e sands derived from surrounding outcrops of higher eleva-t i o n s r e s u l t s i n d i r t commonly accumulating on the snow i n snowbed s i t e s dur-ing each summer. Warren Wilson (1958) has suggested that i t i s p a r t l y t h i s process that causes the b u i l d up of f i n e organic s o i l s that p r e v a i l i n such s i t e s as w e l l as being a source f o r the p o s s i b l e i n c r e a s e i n s o i l n i t r o g e n . The mean annual s n o w f a l l at Shingle Point i s 29.6 inches over 23 days and at Inuvik 68 inches over 100 days (D.O.T.M.B., 1966). Snow may f a l l any time during the summer months. In 1965 no snow v/as recorded from June 1st -August 23rd., while i n 1966 snow was recorded on J u l y 25, 26 and 28 and August 9 and 10. Snowfall increases i n both frequency and amount i n l a t e August i n the f o o t h i l l s and accumulation g e n e r a l l y begins i n September. By l a t e October and e a r l y November s n o w f a l l ceases. Snow accumulates i n c e r t a i n s h e l t e r e d s'ites due to strong winds and reaches i t s maximum depth by the f o l -lowing s p r i n g . Exposed r i d g e tops and escarpment edges may be bare during most of the w i n t e r due to wind a c t i o n . On such s i t e s v e g e t a t i o n i s v i r t u a l l y non-existent because of the abrasive a c t i o n of d r i f t i n g sand and i c e c r y s t a l s Although no records are a v a i l a b l e i n d i c a t i n g whether the snow depth was i n i t i a l l y equal on opposite sides of the v a l l e y s l o p e s , i t was observed that i n the two study areas west f a c i n g tundra slopes were f r e e o f snow at l e a s t two weeks before the east f a c i n g slopes. In the s p r i n g snow melt i s v a r i a b l e but higher exposed e l e v a t i o n s are u s u a l l y f r e e of snow by mid-May. Li g h t i n t e n s i t y , q u a l i t y and d u r a t i o n are exceedingly important f a c t o r s i n the tundra environment. They a f f e c t not only s o i l and a i r temperatures, 15 humidity and s o i l moisture, but a l s o the energy flow w i t h i n the ecosystem ( B l i s s , 1962). Few records are a v a i l a b l e on s o l a r r a d i a t i o n , but i t i s g e n e r a l l y accepted that the s o l a r energy i n the a r c t i c may equal or exceed, f o r short d u r a t i o n s , t h a t r e c e i v e d at m i d - l a t i t u d e s on a 24 hour b a s i s . The exposure and degree of a slope profoundly i n f l u e n c e i t s a i r and . s o i l temperature as w e l l as the s o i l moisture of the m i c r o c l i m a t e . Along the coast where a l l slopes would r e c e i v e about the same amount of heat energy sky r a d i a t i o n tends to moderate d i f f e r e n c e s of exposure. However, the same cannot be s a i d f o r the f o o t h i l l s where abrupt changes i n topography f r e q u e n t l y occur. Many steep slopes w i l l be shaded some time during the 24 hour p e r i o d . This was the case on some east and south f a c i n g slopes i n the Canoe Lake area. S o i l s S o i l s of the Alaskan A r c t i c Slope have rece i v e d considerable a t t e n t i o n i n the l a s t f i f t e e n years from Dr. J . C. F. Tedrcw and h i s students. The vast amount of i n f o r m a t i o n t h a t has been compiled on t h e i r genesis, morphology, chemical and p h y s i c a l p r o p e r t i e s has r e s u l t e d i n an a r c t i c , s o i l c l a s s i f i c a t i o n . This has been accomplished by arranging the s o i l s i n a drainage catena i n a s i m i l a r manner to those i n other c l i m a t i c regions. (Tedrow et a l . , 1958). The work of t h i s group covers the Coastal P l a i n s , F o o t h i l l s and Brooks Mountain Range to an extent t h a t a l l the major s o i l s are known. D e t a i l e d mapping has been c a r r i e d out on the c o a s t a l s o i l s around Barrow (Drew, 1957) and the North-ern Brooks range (Brown, 1962). Few s o i l s s t u d i e s have been undertaken i n the Canadian A r c t i c and none on the s c a l e of those of Tedrow and h i s students. F e u s t a l et a l . (1959) reported l a b o r a t o r y data from 57 s o i l samples c o l l e c t e d i n A r c t i c Canada. P r o f i l e c h a r a c t e r i s t i c s were poo r l y defined i n these s o i l s although analyses of the samples showed an accumulation of surface organic matter, a wide range of C/N r a t i o s and hydrous mica as the dominant c l a y m i n e r a l . Since f i e l d r e l a t i o n -ships were not discussed by the authors, the s o i l m a t e r i a l s were as " l i t h o s o l a s s o c i a t e s " of what i s recognized as t r u e tundra. Leahey (1947) has described some c h a r a c t e r i s t i c s of the s o i l s adjacent to the Mackenzie R i v e r i n the Northwest T e r r i t o r i e s . The t h i c k n e s s of p a r t l y decomposed organic matter on the surface v a r i e s with•topography, the t h i n n e s t being on the k n o l l s or r i d g e s and the t h i c k e s t on lower slopes and depressions. Drew (1957) i n t e r p r e t e d t h i s c o n d i t i o n as s i m i l a r to the peaty surfaced tundra s o i l s of northern Alaska. Tedrow and Douglas (1964) described the s o i l s i n a small area of west c e n t r a l Banks I s l a n d . They concluded that the s o i l s there were predominantly w e l l - d r a i n e d w i t h many high a r c t i c a f f i n i t i e s . Because of the dry d e s e r t - l i k e appearance of most of the s o i l s they were designated c o l -l e c t i v e l y as p o l a r desert r a t h e r than tundra. Many o f the s o i l s have s a l t s accumulated at the surface. Day and Rice (1964) described the c h a r a c t e r i s t i c s of some permafrost s o i l s under d i f f e r e n t types of v e g e t a t i o n i n the lower Mackenzie R i v e r , NWT. Two p r o f i l e s were described from j u s t east of Reindeer S t a t i o n on the east s i d e of the Mackenzie D e l t a . The f i r s t s i t e represented the r i d g e s and upper slopes and was c l a s s i f i e d as a regosol (Tedrow et a l . , 1958). The second s i t e was at the base of a g e n t l e slope and had c h a r a c t e r i s t i c l o s e l y r e l a t e d to those described by Tedrow et a l . (195S) as belonging to the upland tundra s o i l group. Smith (1956) i n s t u d i e s on Spitzbergen described the s o i l s and arranged them i n a broad drainage catena from the (dry) l i t h o s o l s of the rugged elevated s i t e s to the (wet) tundra s o i l s o f the lower* polygonal and s o l i f l u c t i o n areas. A l s o described were the organic i n c l u s i o n s i n the lower horizons and the mot-t l e d c o n d i t i o n of the mineral m a t e r i a l i n the upper p o r t i o n of the p r o f i l e . The conclusions reached by Smith agree i n general w i t h current Russian t h e o r i e s The vast m a j o r i t y of a r c t i c s o i l s t u d i e s to date have been undertaken by Russian s o i l s c i e n t i s t s . Tundra s o i l s were f i r s t d i s t i n g u i s h e d by Dokuchaev (Margu l i s . 1954) more than a century ago when he named the f i v e n a t u r a l s o i l zones. Middendorf (1864) recognized .two types of tundra; a high tundra with r e l a t i v e l y dry mineral s o i l s and a low tundra with wet peat s o i l s b earing a bog or marsh v e g e t a t i o n . Sochava. (1933) i m p l i e s f o r the tundra s o i l s o f the Anabar R i v e r Basin a drainage sequence ranging from w e l l drained s o i l s supporting l i c h e n s to wet saturated gley s o i l s with a s s o c i a t e d grasses and sedges. In the same region he detected podzol formation on sandy m a t e r i a l i n w e l l drained p o s i t i o n s . Sheludikova (1938) recognized i n the I n d i g i r k a R i v e r Basin four t u n d r a - s o i l v e g e t a t i o n a s s o c i a t i o n s ranging from shrub tundra through l i c h e n , grassy tundra and marshy tundra. There are s t i l l d i f f e r e n c e s o f op i n i o n i n the Russian l i t e r a t u r e on wheth-er tundra s o i l s represent a unique type of s o i l formation. Gorodkov (1931) suggested that there i s no b a s i s f o r c o n s i d e r i n g A r c t i c regions unique i n terms of pedologic processes. He presented evidence i n d i c a t i n g that the d i f f e r e n c e between gleyey and p o d z o l i c - g l e y e y s o i l s i n the northern f o r e s t zone and the tundra i s not q u a l i t a t i v e but q u a n t i t a t i v e . F i l a t o v (1945), on the other hand, s t a t e d that the lack of widespread evidence o f p o d z o l i z a t i o n i n the A r c t i c , coupled w i t h the peaty surface gieyed c o n d i t i o n and general water s a t u r a t e d nature of the s o i l s , i n d i c a t e that a r c t i c s o i l s should not be thought o f g e o g r a p h i c a l l y i n terms of a p o d z o l i c process. The g e n e t i c s o i l s o f A r c t i c Alaska have been c l a s s i f i e d as L i t h o s o l s , Regosols, A r c t i c Brown (shallow and normal phase), Upland Tundra, Meadow Tundra, H a l f Bog and Bog (Tedrow and Cantlon, 1958., Tedrow et a l . 1958). L i t h o s o l s occur i n the mountains and the f o o t h i l l s where, i n exposed areas, excessive weathering by wind r e s t r i c t s the cumulative processes of s o i l formation. A t h i n l a y e r of organic matter i s sometimes present i n the s h e l t e r e d s i t e s where depauperate v e g e t a t i o n s u r v i v e s , but such s i t e s are very scarce. Regosols occur i n y o u t h f u l areas of w e l l drained t a l u s , a l l u v i a l and outwash d e p o s i t s . Genetic p r o f i l e s are g e n e r a l l y absent because of t h e i r youthfulness. Such areas are g e n e r a l l y major drainage pathways w i t h excessive water passing over 18 them 'hiring the e a r l y summer thaw. Because of t h i s the permafrost t a b l e i s always at a cons i d e r a b l e depth, up to s i x feet (2 m). A r c t i c brown s o i l s are g e n e r a l l y present on r i d g e tops, escarpment and t e r r a c e edges in. the mountains and f o o t h i l l s , and on s t a b l i z e d dunes along the coast. These s i t e s c o n s i s t of coarse sands and g r a v e l l y m a t e r i a l t h a t , because of improved drainage and a e r a t i o n , give r i s e to a t h i c k e r a c t i v e l a y e r . They are designated by Tedrow (1963) as the most developed s o i l although i n h i s st u d i e s they c o n s t i t u t e d l e s s than one per cent of the t o t a l area s t u d i e d . The a c t i v e l a y e r may be of considerable thickness as much as three to f i v e f e e t (1-1 3/4 m) and i s always g r e a t e r where sand i s present. The a r c t i c brown pro-f i l e s g e n e r a l l y d i s p l a y a narrow colour v a r i a t i o n , the upper h o r i z o n of dark brown organic matter grading to yellow-brown and grey-brown with depth. Bur-rowing animals probably c o n t r i b u t e to the c h a r a c t e r i s t i c brown c o l o u r a t i o n o f the lower horizons by t h e i r use of v e g e t a t i v e m a t e r i a l s f o r n e s t i n g . These w e l l - d r a i n e d s o i l s possess an A-B-C h o r i z o n sequence. Tedrow and H i l l (1955), i n a l l the a r c t i c brown s o i l s s t u d i e s , have found evidence of c l a y accumulation i n the A and B horizons while i n the C h o r i z o n there i s more medium to f i n e sand. These s o i l s thaw i n l a t e s p r i n g and remain i n an unfrozen s t a t e through-out the summer at moisture l e v e l s c o n s i d e r a b l y deeper than that of most s o i l s on the A r c t i c Slope. (Tedrow and H i l l , 1955).- The organic matter concentration i s g r e a t e r i n the upper A l a y e r s and decreases g r a d u a l l y with depth. Tedrow et a l . (1958) have d i s t i n g u i s h e d an a r c t i c brown shallow phase that i s g e n e r a l l y found at higher e l e v a t i o n s . There the bedrock i s w i t h i n 12-16 inches (30-45 cm) of the surface and the drainage i s good. Both the normal and shallow s o i l types are formed under a cover of dwarf shrubs, herbs, sedges, grasses, mosses and l i c h e n s . Kreida (1958) and other Russian workers have a l s o noted the r a r e phenom-enum of a r c t i c brown s o i l but they conclude that i t i s a r e l i c of ancient s o i l - f o r m i n g processes at a p e r i o d of c l i m a t i c optimum. Because of improved, drainage Tedrow and h i s co-workers (1958) contend that the a r c t i c brown s o i l i s nearer to a tru e zonal s o i l and that the gleyey tundra s o i l i s an i n t r a -zonal (hydromorphic) s o i l . On the other hand, recent Russian workers ( K r e i d a , 1958, Mikhaylov, 1961, and Karavayeva, 1965) suggest that because tundra s o i l s are widespread they are zonal s o i l s and that the a r c t i c brown s o i l s are t r a n -s i t i o n a l because of t h e i r l i m i t e d d i s t r i b u t i o n . This was als o the view of e a r l i e r Russian i n v e s t i g a t o r s such as G l i n k a and L i v e r o v s k i y (Mikhaylov, 1961) Of a l l the a r c t i c s o i l s s t u d i e s to the present, tundra s o i l s have r e -ceived by f a r the great e s t a t t e n t i o n . Kreida (1958), i n h i s s t u d i e s on tundra s o i l s of the northern U.S.3.R., described t h e i r formation as due to the i n t e r -a c t i o n of biochemical and leaching processes coupled with f r o s t displacement. In recent years tundra s o i l s have been s t u d i e d to a considerable depth; both the a c t i v e l a y e r and the upper p o r t i o n of the permafrost t a b l e were i n v e s t i -gated. Some i n t e r e s t i n g morphological features v/ere revealed, the most im-portant being the i n c l u s i o n of concentrations of organic matter i n the upper p o r t i o n o f the permafrost. (Mackay, 1958., and Tedrow, 1965). Tundra s o i l s are by f a r the most widespread of the a r c t i c s o i l s . They are always p o o r l y drained mainly because of the impervious permafrost, low temperatures and n a t u r a l p r e c i p i t a t i o n , and are a c t i v e f o r only two to four months of the summer. One c h a r a c t e r i s t i c common to these p o o r l y drained, s o i l s i s the g l e y i n g that occurs i n the upper mineral h o r i z o n d e s p i t e the p e r s i s t e n t presence of carbonates throughout many tundra p r o f i l e s . The organic l a y e r at the surface i s from 2-10 inches (5-25 cm) t h i c k , moderately to s t r o n g l y a c i d i c which tends to increase with depth. On the b a s i s of p r o f i l e morphology o f the tundra s o i l s of a r c t i c A l a s k a , Tedrow and Cant Ion (1958) have recognized both an upland and a meadow tundra. The upland tundra which occurs on r e l a t i v e l y d r i e r slopes and rounded h i l l t o p s has l e s s organic matter and greater o x i d a t i o n . t h a n the meadow tundra s o i l s . Vegetation cover i s u s u a l l y l e s s w i t h more xer o p h y t i c species being present. Improved drainage gives r i s e to a t h i c k e r a c t i v e l a y e r . Meadow tundra s i t e s are more frequent on the lower reaches of the f o o t -h i l l s and c o a s t a l p l a i n where drainage i s g e n e r a l l y poorer. P r o f i l e s i n t h i s type show cons i d e r a b l e v a r i a t i o n . Local f a c t o r s , such as the complex p a t t e r n of ground i c e i n the form of i c e wedges, veins and l e n s e s , and the amount and c h a r a c t e r of the organic matter at the s u r f a c e , leave t h e i r marks on the pro-f i l e morphology (Tedrow et a l . , 1958). At any time and place tundra s o i l morphology r e f l e c t s two sets of processes. One r e l a t e s to s o i l formation and i n v o l v e s organic matter production and a m i l d a c i d - g l e i process; the other i s the d e s t r u c t i v e p h y s i c a l process of f r o s t a c t i o n i n c l u d i n g s o l i f l u c t i o n . In the p o o r l y drained areas of the lowlands, patterned ground i n f l u e n c e s the d i s t r i b u t i o n of moisture and r e s u l t s i n s a t u r a t i o n , o f t e n with standing water present throughout the summer.months. S o i l s formed under such r e s t r i c t e d drainage are c h a r a c t e r i z e d by a heavy accumulation of organic matter i n which decomposition i s impeded. G e n e r a l l y , the organic l a y e r i s t h i c k , c o n s i s t i n g of Sphagnum - Carex mixtures that overlay a mineral l a y e r . The organic s o i l s are subdivided: h a l f - b o g w i t h organic accumulations approximately 6-12 inches (15-30 cm) i n t h i c k n e s s , and bog w i t h an organic l a y e r at times exceeding 4 f t (120 cm) (Tedrow et a l . 1958). The pH values of these bog s o i l s i s g e n e r a l l y m i l d to s t r o n g l y a c i d . In p o o r l y drained s o i l s . t h e development of patterned ground i n f l u e n c e s the d i s t r i b u t i o n o f moisture by breaking up the g e n e r a l l y smooth topography and g i v i n g r i s e to a m i c r o r e l i e f where s o i l morphology i s v a r i a b l e . Low-centred polygons have pools of standing water; the p e r i p h e r a l tussock rims are mostly narrow, prominent and d r i e r . The organic l a y e r i n the low-centered polygon, while t h i c k , has a narrow a c t i v e l a y e r due to poor drainage. The high-centered polygons are peaty and covered with low shrubs and herbs and sedges. The f i s s u r e s are wet and vegetated by sedges and mosses. The a c t i v e 91 l a y e r i n the high-centered polygon i s gre a t e r under the mounds than under the f i s s u r e s . This i s r e l a t e d to improved drainage on the mound, and the i n -s u l a t i n g e f f e c t of the t h i c k moss cover i n the f i s s u r e s , which prevents heat p e n e t r a t i o n during the thaw p e r i o d . The t r a n s i t i o n from -low-centered to high-centered polygons i s accomplished through a widening o f the peaty r i d g e s , the growth of peat and peaty mounds i n the low c e n t e r s , and the s u b d i v i s i o n of the l a r g e r polygons i n t o s m a l l e r ones (Mackay, 1963). . From t h i s may be seen a t r a n s i t i o n from the bog ( l o w - c e n t e r e d polygon) to the hal f - b o g (high-centered polygon). On those b e t t e r drained h a l f - b o g s o i l s v e g e t a t i o n becomes e s t a b l i s h e d t h a t - c l o s e l y resembles communities normally found on meadow and o c c a s i o n a l l y upland tundra s i t e s . In r e f e r r i n g to f r o s t - a c t i o n s e v e r a l authors have i m p l i e d that s o l i f l u c t i o n and mechanical s t r e s s e s and tensions developed i n tundra s o i l s during the f r e e z -i n g are r e s p o n s i b l e f o r so much "mixing" i n tundra s o i l s t hat no c l a s s i f i c a t i o n scheme i s a p p l i c a b l e when based on genetic morphology. Gorodkov (1931) r e c -ognized the danger i n producing a fundamental c l a s s i f i c a t i o n of tundra s o i l s from the standpoint of f r o s t caused f e a t u r e s . His work i n v o l v e d a genetic c l a s s i f i c a t i o n of A r c t i c s o i l s and recognized n a t u r a l l y o c c u r r i n g s o i l bodies r e s u l t i n g from the weathering of parent m a t e r i a l under the i n f l u e n c e of c l i -mate, drainage and a s s o c i a t e d l i v i n g organisms. In developing a c l a s s i f i c a t i o n f o r the Alaskan Coastal P l a i n s o i l s , Drew . (1957) found i t necessary to use m i c r o r e l i e f as w e l l as s o i l morphology. De-t a i l e d , s t u d i e s i n p o o r l y drained s o i l s showed that patterned ground i n f l u e n c e s t h e d i s t r i b u t i o n of s o i l moisture and organic, and mineral m a t e r i a l w i t h i n t h e s o i l . In developing high-centered polygons the center and f i s s u r e (trough) s o i l p r o f i l e may be s i m i l a r . The s o i l morphology i s slow to r e f l e c t the change i n moisture c o n d i t i o n s , i n s t e a d the d i f f e r e n c e s are c l e a r l y shown i n the species composition of the pla n t communities. Tedrow et a l . (1958) have b a s i c a l l y f o l l o w e d Gorodkov's fundamental c l a s s i f i c a t i o n , but at the same time have recognized the e f f e c t of perma-f r o s t , f r o s t - a c t i o n and patterned ground (where a p p l i c a b l e ) i n t h e i r de-te r m i n a t i o n of the major genetic s o i l s of northern Alaska. Probably the most complete o f a l l s o i l c l a s s i f i c a t i o n t e x t s i s The S o i l s of Europe, Kubiena (1953). While the work i s r e s t r i c t e d t o the most important European s o i l formations i t does i n c l u d e d e t a i l e d i n f o r m a t i o n on the F i n n i s h A r c t i c and nearby A r c t i c Islands as w e l l as the i d e n t i f i c a t i o n of A l p i n e S o i l s Many s o i l c h a r a c t e r i s t i c s o u t l i n e d by Kubiena are r e a d i l y recognized i n the Low A r c t i c Subalpine Zone of western North America. Permafrost - The E f f e c t s on Vegetation and S o i l The t r e e l i n e , as i n d i c a t e d i n the A t l a s o f Canada, approximates the southern l i m i t of continuous permafrost (Brown, 1960) between the Hudson's Bay and the Yukon-Alaska boundary. This southern l i m i t l i e s between the -3.9°C (25°F) and -1.1°C (30°F) annual isotherms. The greatest depths of permafrost are found under severe c l i m a t i c c o n d i t i o n s where annual p r e c i p i t a -t i o n i s l i g h t . The depth of permafrost and the thickness o f the a c t i v e l a y e r are dependent on mean annual temperature and the type and de n s i t y of the veget a t i o n on the ground ( s o i l ) s u r f a c e . Vegetation has a d i r e c t i n f l u e n c e on the permafrost by i t s thermal p r o p e r t i e s which determine the q u a n t i t y of heat that enters and leaves the ground i n which permafrost i s present. In the high a r c t i c and a r c t i c - a l p i n e regions v e g e t a t i o n has l i t t l e i n f l u e n c e on the a c t u a l t h i c k n e s s of permafrost because of i t s sparseness and short v e g e t a t i v e season (Brown, 1963). The organic matter or peaty l a y e r present i n the upper s o i l h o r i z o n of the tundra s o i l s i s very hygroscopic. During the e a r l y summer, the peaty h o r i z o n , because o f a high i c e content, owing to i t s l a r g e thermal c a p a c i t y , prevents the warming of the underlying s o i l h o r i z o n . The heat i s consumed i n thawing the i c e and evaporation of the water. A f t e r a d r y i n g p e r i o d the upper surface of peat prevents the warming and dryi n g out of the lower lay e r s becaus 23 of i t s low thermal c o n d u c t i v i t y . The i n s u l a t i n g peat l a y e r that d r i e s out during the summer has a high i c e content on f r e e z i n g i n winter. Water present i n t h i s l a y e r comes from autumn r a i n and snow. I t becomes a good heat conductor and o f f e r s l i t t l e r e s i s t a n c e to c o o l i n g of the lower horizons.' In summer the heat i s consumed i n melting the i c e and evaporating and warming the water, i n winter there i s only c o o l -i n g and f r e e z i n g . Consequently, the peat o f f e r s l e s s r e s i s t a n c e to the c o o l -in g o f the s o i l i n the w i n t e r than to warming i n the summer. In t h i s way, i t co n t r i b u t e s to the predominance o f w i n t e r c o o l i n g over summer thawing ( T y r t i k o v , 1959). This i m p l i e s that f r e e z i n g increases s o i l c o n d u c t i v i t y as i c e i s a b e t t e r conductor of heat than water. The net losses i n w i n t e r , when s o i l i s f r o z e n , w i l l be greater than summer gains through the unfrozen s u r f a c e , f o r the same temperature d i f f e r e n t i a l . The e f f e c t s o f permafrost on ve g e t a t i o n and the reverse are q u i t e d r a s t i c . Permafrost impedes s o i l development by a f f e c t i n g moisture r e l a t i o n s h i p s , leach-i n g , temperature and root depth. On the a r c t i c slope, depth of permafrost de-pends on the type o f parent m a t e r i a l , microtopography, macrotopography, c l i -mate and v e g e t a t i o n cover and other r e l a t e d f a c t o r s . Since the permafrost t a b l e i s impervious to water that accumulates with the thawing a c t i v e l a y e r and low p r e c i p i t a t i o n , drainage water moves mainly l a t e r a l l y downslope throughout the thawed surface l a y e r . This drainage water f i n d s i t s way to the myriad of drainage pathways that transect' the slopes and e v e n t u a l l y flows i n t o major streams. Drainage i s v i r t u a l l y non-existent i n the f l a t lowlands and water l o s s i s mainly through t r a n s p i r a t i o n and evaporation. The s a t u r a t e d c o n d i t i o n of the a c t i v e l a y e r i n s i t e s of poor drainage leads to reduced a e r a t i o n and impoverishment, o f n u t r i t i v e substances that may be r e l a t e d to l i m i t e d m i c r o b i a l a c t i v i t y considered to take place during the summer (Boyd, 1958). This c o n d i t i o n leads to an increase i n the accumulation of organic matter. On s l o p i n g surfaces where the a c t i v e l a y e r i s t h i c k e r and s i l t - r i c h s o i l s o v e r l a i n by peat and t u r f predominate, surface drainage i s impeded by the v e g e t a t i o n as w e l l as by permafrost. Where the slopes are greater than 20-30°, t h i s r e s u l t s i n a downslope movement ( s o l i f l u c t i o n ) of s u p e r f i c i a l s o i l and d e b r i s . This r e s u l t s mainly from the expansion of the s o i l normal to the slope during the heat i n g and f r e e z i n g and i s fol l o w e d by v e r t i c a l subsidence upon c o o l i n g and thawing (Sigafoos and Hopkins, 1952). This phenomenum i s most evident during the autumn f r e e z i n g c y c l e . Hopkins and Sigafoos (1951) i n a study of the r o l e of f r o s t t h r u s t i n g i n the formation of tussocks'' concluded these were formed only by the d i f f e r e n t i a l upward move-ment of the s o i l beneath the tussock. Downslope movement was shown to be i n the autumn during the freeze-thaw periods p r i o r to the w i n t e r freeze. In-d i v i d u a l tussocks s t u d i e d during the summer showed that the l i v i n g roots be-neath the culm base extended v e r t i c a l l y downward from the ro o t s t o c k . The brown dead roots o f the previous seasons were contorted and t w i s t i n g i n d i c a t i n g that a f t e r the roots died strong pressures were exerted upward through the mound against the roots and r o o t s t o c k s . The adherence of the root mass to the mineral s o i l and the p h y s i c a l r e s i s t a n c e of the root mass to s o i l movement prevents any downslope movement during the prolonged periods o f thaw. Ad-d i t i o n a l l y , the tussock v e g e t a t i o n e x t r a c t s water from the s o i l thereby help-ing to keep i t l e s s f l u i d (Hopkins and Sigafoos, 1954). Root systems are t y p i c a l l y m a t - l i k e where permafrost i s c l o s e to the sur-face and develop p r i m a r i l y i n the h o r i z o n t a l plane. The roots w i t h i n t h i s nar-row a c t i v e l a y e r are entwined and a s s i s t i n g i v i n g a d d i t i o n a l anchorage to the p l a n t s . Removal of the v e g e t a t i v e cover permits g r e a t e r heat p e n e t r a t i o n , increase i n s u rface a i r c i r c u l a t i o n and an increase i n depth of thaw. This r e s u l t s i n 1. A tussock i s a s i n g l e p l a n t that grows on a small mound of mineral s o i l . The root stock forms a cap around the mineral s o i l . 25 the m e l t i n g of the permafrost i c e which can lead to r a p i d e r o s i o n , sink holes and other types of thermokarst forms of r e l i e f . Gregory (1957) has st a t e d that the v e g e t a t i v e cover, which acts as an i n s u l a t i n g cover, i s oft e n i n eco-l o g i c a l balance with the l e v e l of permafrost i n the ground. The t h i c k mats of mosses that are present i n wet s i t e s i n d i c a t e t h e i r i n s u l a t i n g p r o p e r t i e s during the summer by a very shallow a c t i v e l a y e r beneath the mat. The d i u r n a l and seasonal range of s o i l temperatures i n bog, and to a de-gree i n meadow tundra s o i l s , i s narrower than that of the deeper thawed a r c t i c brown s o i l s . The f i b r o u s peaty i n s u l a t i n g surface and r e s t r i c t i o n o f drainage by permafrost keeps these s o i l s at high moisture l e v e l s during the thaw p e r i o d . Permafrost l e v e l s i n the major s o i l s of the Alaska slope vary due to moisture content of the s o i l . Tedrow et a l . (1958, 1959) during t h e i r extensive s t u d i e s have determined f o r the major s o i l s an average depth f o r the permafrost at the end of the summer thaw. On ridges and escarpments where a r c t i c brown s o i l s form, the permafrost t a b l e may be 3-5 f t (1-2 m) deep. In l i t h o s o l s , where there i s only a shallow s o i l , the un d e r l y i n g bedrock and/or coarse ma-t e r i a l i s s t i l l considered permafrost because the mean annual temperature i s below -1.0°C. Top o g r a p h i c a l l y , the tundra s o i l slopes are very i r r e g u l a r , c o n s i s t i n g of hummocks and depressions. The surface p a t t e r n of the permafrost i s u s u a l l y a m i r r o r image o f the s o i l s u r f a c e . Where there i s a surface r i s e there i s a permafrost hollow. The poor l y drained organic mineral tundra s o i l s that cover vast areas of the a r c t i c u s u a l l y have a permafrost t a b l e at a depth of l e s s than 2 f t (60 cm). The upper p o r t i o n o f the frozen l a y e r has i n c l u s i o n s o f organic matter and organic s t a i n e d i c e . At a depth of 2-4 f t (60-130 cm) below the permafrost surface the m i n e r a l ' m a t e r i a l i s f r e e o f organic s t a i n i n g (Tedrow et a l . , 1958). In bog s o i l s the frozen surface i s g e n e r a l l y higher than i n the tundra s o i l s , and may be only 1-2 f t (30-65 cm) deep. Although regosols c o n s i s t of f i n e m a t e r i a l and show l i t t l e development, they g e n e r a l l y have a 26 deep permafrost t a b l e . This can be a t t r i b u t e d to the f a c t t h a t they are w e l l drained and have water moving over them continuously during much of the sum-mer. On the higher s l o p e s , where there i s l e s s a l l u v i u m , the permafrost i s c l o s e r to the surface because there i s l e s s water movement than on the lower s l o p e s , lake edges and creeks. Benninghoff (1963) has suggested that p l a n t e c o l o g i s t s who have under-taken recent s t u d i e s of northern v e g e t a t i o n have appeared too confident i n t h e i r a b i l i t y t c evaluate the i n t e n s i t y of f r o s t a c t i o n or permafrost i n s o i l s based on the nature o f the ve g e t a t i o n on the s i t e . However, while the study o f permafrost, as r e l a t e d to both vegetation and s o i l , has r e c e i v e d l i t t l e study, c o n s i d e r a b l e i n f o r m a t i o n can be forthcoming p r o v i d i n g p l a n t e c o l o g i c a l s t u d i e s are confined to reasonably small areas. In t h i s manner, v a l u a b l e i n f o r m a t i o n can be obtained on the thickness o f the a c t i v e l a y e r and i t s r a t e of thaw under d i f f e r e n t p l a n t communities during the v e g e t a t i v e season. 27 M L IMA're M i c r o c l i m a t i c Synthesis The i r r e g u l a r topography at Canoe Lake has given r i s e to many sharply defined h a b i t a t s . The communities a s s o c i a t e d w i t h these h a b i t a t s u s u a l l y r e f l e c t sharp d i f f e r e n c e s i n s o i l moisture. However, no q u a n t i t a t i v e data were c o l l e c t e d to s u b s t a n t i a t e t h i s hypothesis. In order to determine what, other environmental f a c t o r s might be r e l a t e d to these sharp boundaries c l i m a t i c data were c o l l e c t e d from s e l e c t e d s i t e s . M i c r o c l i m a t i c comparisons would then be p o s s i b l e between d i f f e r e n t , community types. Nine weather s t a t i o n s (Figure 7) were e s t a b l i s h e d on J u l y 1 s t, 1966, and operated continuously u n t i l August 28th, 1.966, to obt a i n q u a n t i t a t i v e and q u a l i t a t i v e data on temperature and r e l a t i v e humidity. One Fuess hygro-thermograph was placed i n each of ten p r e v i o u s l y analyzed communities across the v a l l e y . The instruments were i n c o l l a p s i b l e screens, s i m i l a r to the Stevenson type, and placed on boards d i r e c t l y on the ground. (Figure 8). The communities ranged i n e l e v a t i o n from 1050-2100 f t , and had e i t h e r west f a c i n g , east f a c i n g or t o t a l exposures. A complete summary of the maximum and m i n i -mum temperatures and r e l a t i v e humidity f o r a l l s t a t i o n s are presented i n Appendix I I . No records were kept o f a c t u a l p r e c i p i t a t i o n during t h i s p e r i o d . While m i c r o c l i m a t i c d i f f e r e n c e s were not abrupt i n t h i s area there were some notable d i f f e r e n c e s . These were a r e s u l t l a r g e l y of v a r i a t i o n s i n ve g e t a t i v e cover, topography, s l o p e , exposure and probably the combined ef-f e c t of the i n s o l a t i o n - r a d i a t i o n balance. However, no data are a v a i l a b l e on the l a t t e r . Based on d a i l y temperature readings a l l s t a t i o n s show r a t h e r uniform p a t t e r n s . Degree of slope and slope exposure have a profound i n f l u e n c e upon a i r and s o i l temperatures as w e l l as on s o i l moisutre and. humidity o f the micro-c l i m a t e . The wi n t e r winds i n the Canoe Lake area are predominantly from the northwest so that l i t t l e snow accumulation on the scarp slopes of the north-t o f o l l o w page L o c a t i o n o f t h e n i n e w eather s t a t i o n s e s t a b l i s h e d i n t h e Canoe Lake s t u d y a r e a , and o p e r a t i o n a l f o r J u l y and August 1966. 28 south cuestas. Whether a c t u a l snow depth on the east f a c i n g slopes was greater than the west f a c i n g slopes was not determined. However, the l a r g e number of drainage pathways on the east f a c i n g s l o p e s , with i n c r e a s i n g l y t a l -l e r S a l i x communities at lower e l e v a t i o n s , were prime s i t e s f o r snow accumu-l a t i o n during the w i n t e r . During the e a r l y summer thaw snow disappears more r a p i d l y from the west f a c i n g slopes than on the opposite slopes. In 1965 the west f a c i n g slopes were c l e a r o f snow by May 27th, w h i l e the east f a c i n g slopes were not c l e a r u n t i l June 6th, of l a t e r . Figure 8. Weather s t a t i o n No. 4 i n a Cassiope tetragona dominated s i t e on the east, f a c i n g slope west of Canoe Lake. (Photo by Lambert) M i c r o c l i m a t i c d i f f e r e n c e s are mainly a r e s u l t of the balance between d i r e c t i n s o l a t i o n , d i f f u s e sky r a d i a t i o n and t e r r e s t r i a l r a d i a t i o n ( B l i s s , 1956). There i s a d i f f e r e n c e of 15° between the scarp slope of the cuesta on the east side of Canoe Lake and the dip slope of the western cuesta. The l a t t e r cuesta i s 700 f t higher than the east cuesta so that a f t e r June 21st the midday angle of i n c i d e n c e on the east f a c i n g slope i s reduced d a i l y . During June and e a r l y J u l y , shading has l i t t l e or no e f f e c t on c l i m a t i c patterns f o r those communi-t i e s l a c k i n g shrub cover, because the sun never dropped below the ridges of e i t h e r cuesta. In l a t e J u l y and August d i u r n a l temperature ranges are a f f e c t -ed; i n c r e a s i n g hours of darkness and a decrease i n the angle of i n s o l a t i o n reduce the t o t a l d a i l y i n s o l a t i o n f o r communities on the lower slopes. While the east f a c i n g slope was r e c e i v i n g considerable l e s s d i r e c t i n s o l a t i o n , due to the narrower angle o f i n c i d e n c e , than' the west f a c i n g s l o p e , the August temperatures were higher on the more shaded east f a c i n g than the west f a c i n g slopes. Reasons f o r t h i s d i f f e r e n c e can only be s p e c u l a t i v e . However, the f a c t t h a t the west f a c i n g slopes are more exposed to i n c r e a s i n g l y c o l d e r north-west winds as wi n t e r approaches i s probably a major f a c t o r . The weather data f o r J u l y and August are summarized i n Table 1. During J u l y , f o r comparable s i t e s , the average temperature at 1100 f t f o r S t a t i o n 7 on the west f a c i n g slope was 53.7°F and 53.9°F f o r S t a t i o n 5 on the east f a c i n g slope. Both these s i t e s are i n upland tundra dominated by Eriophorum vaginatum. At 1450 f t • t h e average temperature i n a Betula glandulosa dominated community ( S t a t i o n 8 ) , on the west f a c i n g slope, was 54.8°F. On the opposite s l o p e , i n a Cassiope tetragona dominated community ( S t a t i o n 4 ) , the average temperature was 53.5°F. Average d i u r n a l ranges were the same f o r the two s t a t i o n s at 1100 f t . At 1450 f t the range v/as grea t e r by 3° on the west f a c i n g slope. The highest temperature recorded during t h i s p e r i o d was 85°F on J u l y 12th, at S t a t i o n 8, on the upper l i m i t s o f the west f a c i n g slope. The exposed lowland s t a t i o n , dominated by Eriophorum s c h e u c h z e r i , at the south end of the l a k e , had the lowest monthly averages f o r temperature and r e l a t i v e humidity. Local fog and cloud cover seldom f i l l e d the v a l l e y com-p l e t e l y and high r e l a t i v e humidity values were recorded only during periods of p r e c i p i t a t i o n . The d i u r n a l range here was the highest f o r a l l s t a t i o n s , the TABLE 1 Summary of average Temperature and Relative Humidity data for microclimatic stations at Canoe Lake for July and August 1966 Temperature °F Relative July August Humidity Station and Dominant species Elevation Feet Min. Max. Avg. Diu. Avg. Min. Max. Avg. Diu. Avg. July August 1 Salix phlebophylla 2100 41.7 62.8 52.3 21 36.1 53.5 45.8 15 72.2 72.1 2 Salix pulchra (B2 shrub) 1575 40.7 62.8 51.7 22 35.2 55.8 45.5 20 85.4 84.1 3 Salix pulchra (B2 shrub) 1440 42.1 64.0 53.1 22 35.9 56.5 46.2 21 74.9 86.9 4 Cassiope tetragona 1440 42.1 64.9 53.5 23 39.7 60.3 50.0 21 70.8 69.5 5 Eriophorum vaginatum 1130 42.2 65.6 53.9 23 36.8 59.4 48.1 23 69.9 70.0 6 Salix pulchra (BI shrub) 1050 44.9 61.0 52.9 17 37.3 54.7 45.9 17 78.9 82.9 7 Eriophorum vaginatum 1130 42.1 65.4 53.7 23 36.8 59.9 47.8 23 69.1 68.7 8 Betula glandulosa 1420 41.9 67.7 54.8 26 37.4 60.5 48.9 23 73.8 75.0 9 Eriophorum scheuchzeri 1060 36.4 63.4 49.9 27 28.4 58.5 45.9 30 • 64.5 63.8 average f o r J u l y being 27° and 50° f o r August. The explanation f o r t h i s high range can be r e l a t e d to 'nocturnal' c o o l i n g i n that the c o o l e r a i r on the ridg e tops flows downslope and c o l l e c t s i n t h i s lowland regio n . On the b a s i s of temperature t h i s would be the only s i t e that could be c l a s s i f i e d as a r c t i c tundra because the highest monthly average temperature v/as below 50°F. (Trewartha, 1954). The amphitheatre or draw between 1440-1575 f t on the western cuesta has higher average temperatures at the base ( S t a t i o n 3) than above ( S t a t i o n 2). The d i u r n a l range f o r these two s t a t i o n s averaged the same (22° and 20°) f o r J u l y and August. During J u l y the r e l a t i v e humidity was gr e a t e r at the upper than the lower s t a t i o n . In August t h i s was reversed. Local fog and cloud cover at higher e l e v a t i o n s during J u l y were r e s p o n s i b l e f o r the d i f f e r e n c e . The upper reaches of the western cuesta were f r e q u e n t l y covered by clouds w h i l the highest p o i n t s on the eastern cuesta, at 1500 f t , were covered f o r only s h o r t , i n f r e q u e n t p e r i o d s . S t a t i o n 6, i n a t a l l shrub (BI) S a l i x p u l c h r a community on the west bank of the l a k e , had temperature and r e l a t i v e humidity values comparable t o those of S t a t i o n 3 at the base of the draw i n a low shrub (B2) S a l i x p u l c h r a com-munity. The s h i e l d i n g e f f e c t of the sides of the draw help to reduce a i r turbulence while the steep sides of the draw r e s u l t i n a r e d u c t i o n o f the angle o f inc i d e n c e and t o t a l i n s o l a t i o n . The dense canopy coverage of the l a k e s i d e S a l i x community d e f i n i t e l y a f f e c t e d the o v e r a l l microclimate at the ground l e v e l so th a t d i u r n a l temperature ranges were reduced. The shrub crowns act as a f i l t e r of r a d i a t i o n so th a t the percentage of i n c i d e n t l i g h t reaching the ground i s g r e a t l y reduced. In f o r e s t e d stands i n the sub-alpine zone of B r i t i s h Columbia, Brooke (1966) reported that s i n c e the dense crowns acted as an i n s o l a t i o n - r a d i a t i o n exchange s u r f a c e , temperature gradients were commonly reduced below the crown space than they were i n non-forested s i t e s . 31 S t a t i o n 7 i n a S a l i x p h l e b o p h y l i a dominated community on the summit of the western cuesta had temperatures and r e l a t i v e humidity averages s l i g h t l y below those of s t a t i o n s at lower p o s i t i o n s on the slopes. Due to i t s exposed p o s i t i o n the angle of i n c i d e n c e was considerably g r e a t e r than at any other s t a t i o n . However, a higher frequency of wind and cloud cover combined to re-duce the e f f e c t of increased s o l a r r a d i a t i o n . During J u l y d i u r n a l temperature ranges were s i m i l a r to other s i t e s . In August, i n l i n e w i t h a general c o o l i n g that i s r e l a t e d t c increased wind and p r e c i p i t a t i o n , d i u r n a l ranges were con-s i d e r a b l y lower than any other s i t e . During J u l y , the warmest summer month, m i c r o c l i m a t i c readings at the base of the amphitheatre compared favourably w i t h S t a t i o n 4 (Cassiope tetragona community) at the same e l e v a t i o n on an exposed slope j u s t to the south. How-ever, i n August with a s h o r t e r d a y l i g h t p e r i o d and the s h e l t e r e d p o s i t i o n of the amphitheatre, maximum and minimum temperatures averaged 4° below that of S t a t i o n 4. Colder a i r masses from the northwest are more prevalent so that during the n i g h t c o l d a i r flows downslope i n t o the depression. Geiger (1957) has suggested that temperatures i n t h i s type of draw are mainly the r e s u l t of r e d u c t i o n i n a i r turbulence. The q u a n t i t a t i v e data g e n e r a l l y s u b s t a n t i a t e s the observations discussed e a r l i e r as w e l l as those made by other workers i n s i m i l a r areas of northern Alaska. Because of the o r i e n t a t i o n of the cuestas (north-south) the east f a c i n g d i p slopes are somewhat s h e l t e r e d from the p r e v a i l i n g northwest winds. Vegetative growth i s i n i t i a t e d on the west f a c i n g slopes at l e a s t one week before that on the east f a c i n g slopes. Average temperatures f o r J u l y were higher on the west than the east f a c i n g s l o p e s , i n August they were approxi-mately the same. Drainage pathways are more abundant on east f a c i n g slopes and are s i t e s f o r snow accumulation. S a l i x communities increase i n height at lower e l e v a t i o n s and because of t h e i r dense canopies the d i u r n a l ranges at the 32 ground l e v e l are narrower than i n surrounding communities on the meadow tundra slopes. Temperature patt e r n s i l l u s t r a t e the i n f l u e n c e of n o c t u r n a l c o o l i n g even though the sun was above the horizon from the s t a r t of r e c o r d i n g u n t i l J u l y 10th. Two s t a t i o n s (5 and 6) had low average d i u r n a l ranges. The former because of i t s exposed r i d g e top p o s i t i o n and the l a t t e r because of the dense crown can-opy. Lowest temperatures were recorded between midnight and 6 a.m. (PST). Temperatures rose g r a d u a l l y with the highest readings being recorded between midday and 6 p.m. (PST). Rapid drops i n temperature could, and d i d , occur at any time during the 24 hour p e r i o d , and were always a s s o c i a t e d w i t h snow or f r e e z i n g r a i n . Below f r e e z i n g temperatures were recorded i n J u l y and August, but there appeared to be l i t t l e or no e f f e c t on the p l a n t s . Monthly average r e l a t i v e h u m i d i t i e s were higher at the m i d - e l e v a t i o n s , between 1400-1800 f t , and i n the shrub (BI) communities. R e l a t i v e humidity at Canoe Lake f o r J u l y and August would have been higher i n 1966 than 1965, as consid e r a b l y more p r e c i p i t a t i o n was observed; averages over a longer p e r i o d of years would doubtless lower the averages recorded i n 1966. M i c r o c l i m a t i c d i f f e r e n c e s appear n e g l i g i b l e between communities on the east and west f a c i n g s l o pes. Elevated and lowland s i t e s g e n e r a l l y had lower average d a i l y temperatures than those on the slopes. Minimum d a i l y temperatures were lower i n the low-centered polygon community than the r i d g e top. This i s r e l a t e d to the downs lope move-ment of c o o l e r a i r at n i g h t that s e t t l e s i n depressions. In c o n t r a s t , warmer a i r moves tips lope during the day. VEGETATION The i n i t i a l c r i t e r i a f o r s e l e c t i n g communities were based on t h e i r u n i -f o r m i t y and d i s c r e t e n e s s . The communities were s t u d i e d by means of sample p l o t s which were l o c a t e d where the vegetation was homogeneous. Any one of the environmental f a c t o r s might r e s u l t i n a h a b i t a t of very small s i z e and com-p l e t e l y d i f f e r e n t from those surrounding i t . Where communities covered extensive areas, or were composed of dense shrub the sample plot, was 100 sq. rn. Small d i s c r e t e communities were analyzed using e i t h e r a 16 or 25 sq.m. p l o t . One sample p l o t was s e l e c t e d and analyzed to represent each community. The vegetat 10T) i n 6 3 . ch p l o t was analyzed employing q u a l i t a t i v e and q u a n t i -t a t i v e p h y t o s o c i a l o g i c a l techniques of the Z u r i c h - M o n t p e l l i e r School as modi-f i e d by K r a j i n a (1933). An i n i t i a l survey was made of the sample p l o t i n which the presence of a l l v a s c u l a r p l a n t s , bryophytes aiid l i c h e n s was recorded. Percent coverage was estimated f o r each s t r a t a . Evaluations of species s i g -n i f i c a n c e and s o c i a b i l i t y were then made of a l l species f o r the f o l l o w i n g s t r a t where present. Bj l a y e r Shrubs over 6 f t &2 l a y e r Shrubs 6 inches to 6 f t C l a y e r Herbaceous p l a n t s and woody p l a n t s under 6 inches ( t h i s i n c l u d e d woody p l a n t s that were recorded as shrubs i n other communities). D l a y e r Bryophytes and l i c h e n s ( t e r r i c o l o u s and saxicol ous) Samples of a l l p l a n t species were c o l l e c t e d i n every p l o t during the sum-mer of 1965 f o r p o s i t i v e i d e n t i f i c a t i o n . In 1966 v a s c u l a r p l a n t s of u n c e r t a i n i d e n t i t y , crustose l i c h e n s and a l l bryophytes were c o l l e c t e d . At l e a s t one sample of every plant e n t i t y has been deposited i n the U n i v e r s i t y of B r i t i s h Columbia Herbarium. During l a t e r i d e n t i f i c a t i o n of the bryophytes many u n l i s t e s p e c i e s , e s p e c i a l l y of Hepaticae, were determined and added to the species l i s t of the appropriate community. Q u a l i t a t i v e and q u a n t i t a t i v e data on environmental c o n d i t i o n s c o l l e c t e d f o r each community i n c l u d e d degree of slope p r o f i l e , p a t t e r n of topography, exposure, a l t i t u d e and wind i n f l u e n c e . A complete l i s t of a l l species c o l -l e c t e d are included i n Appendix I. A t o t a l of 166 communities were analyzed. Problems i n Vegetation Synthesis Considerable d i s c u s s i o n has taken place over .the past seventeen years r e -garding the value of c l a s s i f y i n g or o r d i n a t i n g v e g e t a t i o n i n North America. A major p a r t of the controversy centered around these two schools of thought, and one that has not always been s t r e s s e d i s that c l a s s i f i c a t i o n and o r d i n a t i o n are founded on two d i f f e r e n t p h i l o s o p h i e s which cannot s u b s t i t u t e each other. I! The f o l l o w e r s of the Z u r i c h - M o n t p e l l i e r School consider c l a s s i f i c a t i o n to be the primary aim, while those of the Wisconsin School look f o r , and s t r e s s , the continuous nature of v e g e t a t i o n . Cottam and C u r t i s , founders of the Wisconsin School of O r d i n a t i o n , f o l l o w i n g Gleason (1926) r e f u t e the existence of d i s c r e t e n a t u r a l u n i t s ( a s s o c i a t i o n s ) i n v e g e t a t i o n on the b a s i s that v e g e t a t i o n can only be considered as a m u l t i t u d e of a s s o c i a t e d species each possessing d i f -f e r e n t amplitudes of t o l e r a n c e . The a s s o c i a t i o n - u n i t adherent would not disagree w i t h the concept behind t h i s statement or with v e g e t a t i o n being thought of as a continuum. Followers M of the Z u r i c h - M o n t p e l l i e r School grant that a s s o c i a t i o n s i n t e r g r a d e e x t e n s i v e l y (Becking, 1957). However, i n e c o l o g i c a l l y s i m i l a r s i t e s the p l a n t / h a b i t a t i n -formation can be aggregated and defined as the nodurn (Poore, 1964) . C l a s s i f i c a t i o n must e l i m i n a t e t r a n s i t i o n s i f the u n i t s are to become w e l l c r y s t a l l i z e d and d i f f e r e n t i a t e d . D e t a i l e d studies are then r e s t r i c t e d to the u n i t s around the noda. Ordination,on the other hand, looks f o r a l l p o s s i b l e t r a n s i t i o n s by arranging communities (s t a n d s ) , species and environments i n a way i n which i t i s hoped w i l l r e v e a l maximum inf o r m a t i o n about r e l a t i o n s h i p s among them. A r b i t r a r y d i v i s i o n s along the continuum may then be made which w i l l r e v e a l c l a s s e s as they e x i s t (Mcintosh, 1967). In t h i s study a l l p l o t s , i n c l u d i n g s e v e r a l considered t r a n s i t i o n a l , are used to determine the major a s s o c i a t i o n s , because of t h i s s e v e r a l a s s o c i a t i o n s are l e s s d i f f e r e n t i a t e d . A s t a t i s t i c a l a n a l y s i s of samples i s p o s s i b l e (Becking, 1957, Dagnelie, I960, Von Groenevvoud, 1965) where primary concern has been c l a s s i f i c a t i o n , but i t has not been used i n most s t u d i e s . The s u b j e c t i v e synthesis of data i s ac-complished by a s s o c i a t i n g environmental parameters with f l o r i s t i c s t r u c t u r e . Communities are arranged according to s i m i l a r i t y which g e n e r a l l y implies', i n i t i a l s e p a r a t i o n along a moisture gradient. The f l o r i s t i c s t r u c t u r e i s the primary b a s i s f o r c l a s s i f i c a t i o n , but i t i s organized i n t o environmental and physio-gnomic groups. In the p r e l i m i n a r y s y n t h e s i s t a b l e s the communities are grouped by environmental r e l a t i o n s h i p s and/or dominant s p e c i e s . Presence values are determined f o r a l l species and the species are rearranged according to r e l a -t i v e presence and abundance (species s i g n i f i c a n c e ) . Some species of interme-d i a t e presence value may be recognized to form d i f f e r e n t i a l species groups. The suggestion that dominance-types are poor l y s u i t e d to the formal h i e r a r c h y c l a s s i f i c a t i o n of ve g e t a t i o n has been made by Whittaker (1962) on the b a s i s that i t leads to community types of d i f f e r i n g heterogeneity and i n -c l u s i v e n e s s . At the same time, he does admit that they do have a d i s t i n c t p r a c t i c a l advantage. The major problem, t h e r e f o r e , f a c i n g the e c o l o g i s t i n a d i s c u s s i o n of the end r e s u l t s of c l a s s i f i c a t i o n and o r d i n a t i o n i s how valuable and/or u s e f u l are the f i n a l conclusions to a p a r t i c u l a r study. I t would ap-pear that the value of c l a s s i f i c a t i o n i s that i t brings together common informa-t i o n to enable a b s t r a c t i o n s of species groups to be made e f f i c i e n t l y . These a b s t r a c t i o n s are of value i n f o r e s t r y , range management and veget a t i o n mapping. O r d i n a t i o n has an academic appeal which the c l a s s i f i c a t i o n adherent can ap-p r e c i a t e , but i t has no appeal at the p r a c t i c a l l e v e l to those i n v o l v e d i n land management. In the present study the dominant s p e c i e s , c h a r a c t e r i s t i c com-b i n a t i o n of species and a complex of environmental f a c t o r s are c r i t e r i a f o r determining a pla n t a s s o c i a t i o n ( K r a j i n a , 1960). 36 Vegetation 5ynthesis In the i n i t i a l s y n t h e s i s communities were grouped using only dominant v a s c u l a r species. As the bryophyte and l i c h e n i d e n t i f i c a t i o n s were completed they, too, were added to t h e i r r e s p e c t i v e communities i n the tables'. This t a b u l a t i o n of p l o t data was s t a r t e d a f t e r the f i r s t summer's f i e l d work. F o l -lowing the completion of f i e l d work more complete s y n t h e s i s t a b l e s were prepared II f o l l o w i n g standard methods of the Z u r i c h - M o n t p e l l i e r School. Environmental v a l -ues were i n c l u d e d to represent topography, s o i l , exposure, slope and e l e v a t i o n . While i t i s apparent from the s y n t h e s i s t a b l e s that no two p l o t s of the 166 analyzed are e x a c t l y i d e n t i c a l , comparisons of v e g e t a t i o n and environmental data r e v e a l that c e r t a i n p l o t s appear to have many s i m i l a r i t i e s i n both f l o r i s t i c and h a b i t a t c h a r a c t e r i s t i c s . S t a t i s t i c a l analyses of s u b j e c t i v e l y c o l l e c t e d data has been seldom a t -tempted by p h y t o s o c i o l o g i s t s . When used, i t has been p r i m a r i l y to f a c i l i t a t e d e c i s i o n s as to the p l a c i n g of new i n d i v i d u a l s , and to the e x t r a c t i o n of groups at successive l e v e l s of r e l a t i o n s h i p (Lambert and Dale, 1964) . The exhaustive number of comparisons that must be made between f l o r i s t i c and environmental values of a community and other s i m i l a r communities can give r i s e to innumerable e r r o r s . Because of the e r r o r s l i k e l y to be encountered and the large number of species (over 400) that were present i n one or more of the 166 communities s t u d i e d , a computer program was deemed more p r a c t i c a l . The f a c t that the com-puter can operate o b j e c t i v e l y , without e r r o r and c o n s i d e r a b l y f a s t e r than the i n d i v i d u a l makes i t more p r a c t i c a l . The primary o b j e c t i v e of the s t a t i s t i c s ' ' ' program was to consider the v e g e t a t i o n on a p l a n t / p l a n t b a s i s . In a m a j o r i t y of s t u d i e s where a computer program has been used only the dominant s p e c i e s , o r , as i n the case of o r d i n a t i o n adherents, only the dominant trees and herbaceous species have been considered. In t h i s study, both dominants and 1. S t a t i s t i c s i s defined here i n the o l d e r sense of the v/ord to i n c l u d e the n o n - p r o b a b i l i s t i c methods of data s i m p l i f i c a t i o n and generation of hypotheses. non-dominants ( v a s c u l a r s , bryophytes and l i c h e n s ) are considered. Becking (1957) has reviewed the mathematical equations developed by most of the e a r l i e r workers f o r the determination o f f l o r i s t i c s i m i l a r i t y between two veg e t a t i o n u n i t s . The f i e l d data here have been analyzed using a program developed by Ream (1965) and modified by Borden (1967). Comparisons were made by means of the Index of S i m i l a r i t y between any one community and every other community. The index i s b a s i c a l l y a c o r r e l a t i o n c o e f f i c i e n t used when a number of d i f f e r e n t , q u a l i t a t i v e l y expressed measures are a v a i l a b l e f o r the two communities being compared. S i m i l a r i t y here has been based i n i t i a l l y on presence and abundance of i n d i v i d u a l species. The formula used i s 2W X 100, where A i s the A + B~ sum of a l l the measures (abundance and presence) f o r one community, B i s the sum of a l l measures f o r the other community and W i s the sum of the lower v a l -ues f o r each, or the amount which the two communities have i n common. ' The In-dex of S i m i l a r i t y may vary from zero f o r two communities which have no measures i n common to 100 percent f o r two q u a n t i t a t i v e l y i d e n t i c a l communities. F o l l o w i n g the determination of i n d i c e s of s i m i l a r i t y between each of the 166 communities a method of o b j e c t i v e l y determining the degree of a f f i n i t y and r e l a t i v e h i a t u s p o i n t s between groups of communities was sought. C l u s t e r a n a l -y s i s using the weighted p a i r - group method was s e l e c t e d over f a c t o r a n a l y s i s on the b a s i s t h a t i t can be used to r e l a t e u n i t s based on high s i m i l a r i t y co-e f f i c i e n t s f o r d e f i n i n g groups "among e n t i t i e s . The usefulness of f a c t o r anal-y s i s i s l i m i t e d by the amount of computation necessary to produce a simple c l u s t e r using only a small number of species and communities. B a s i c a l l y then, c l u s t e r a n a l y s i s i n i t i a l l y groups together communities i n which the major spe-c i e s present are common to a l l communities i n the group. This type of procedure for e c o l o g i c a l s t u d i e s was f i r s t described by Sorensen (1948). However, he used only presence and absence and was forced to choose a r b i t r a r y values to draw h i s c l u s t e r s . Developments i n the f i e l d of t h e o r e t i c a l ecology and taxonomy f o l l o w i n g the r a p i d developments i n e l e c t r o n i c computers have allowed the ecolo-g i s t to be more o b j e c t i v e i n the syn t h e s i s of f i e l d data. The various methods of c l u s t e r a n a l y s i s have been discussed by Sokal and Sneath (1963). In t h e i r o p i n i o n , the weight p a i r - group method gives the high-est c o r r e l a t i o n with the o r i g i n a l c o r r e l a t i o n c o e f f i c i e n t s . This method per-mits only the most h i g h l y c o r r e l a t e d communities to j o i n at each c y c l e . The new p l o t formed by these p a i r s has f o r i t s s i m i l a r i t y index i n respect to any other p l o t the simple average of i t s component or s i m i l a r i t y i n d i c e s + Sl« . This weighted p a i r - group method shows l e s s d i s t o r t i o n o f the o r i g i n a l s i m i l a r i t y c o e f f i c i e n t matrix and i s considered to be devoid of any a r b i t r a r y c r i t e r i o n o f group formation (Sokel and Sneath, 1963). When species data f o r a large number of s i m i l a r type communities are analyzed the c l u s t e r a n a l y s i s i s biased i n that i t produces d i s c r e t e c l u s t e r s . This may be viewed, however, as an advantage because i t allows n a t u r a l com-munities to be o b j e c t i v e l y c l a s s i f i e d at any l e v e l from the i n d i v i d u a l to the t o t a l range of v e g e t a t i o n over which the samples are considered to be repre-s e n t a t i v e . The most convenient means of r e p r e s e n t i n g the weighted p a i r - group c l u s -t e r s i s by the two - dimensional dendrogram method. Communities are repre-sented on the a b s c i s s a , while the l e v e l of s i m i l a r i t y i s shown on the o r d i n a t e . S i m i l a r i t y c o e f f i c i e n t values between h i g h l y s i m i l a r communities are i n d i c a t e d by the p o s i t i o n o f the highest v e r t i c a l l i n e s that connect the communities represented by h o r i z o n t a l l i n e s . A d d i t i o n a l communities or groups of communi-t i e s are i n c l u d e d i n the c l u s t e r s by computations of s i m i l a r i t y c o e f f i c i e n t s and, thereby, determine the b a s i c form of the dendrogram. The l a r g e r groups of communities, as w e l l as the more d i v e r s e , are a s s o c i a t e d at lower l e v e l s of s i m i l a r i t y . This can then be considered as a measure of v e g e t a t i o n a l homogeneity os determined by the l e v e l s of s i m i l a r i t y between successive c l u s t e r s across the g r a d i e n t , Results of C l u s t e r A n a l y s i s The l e v e l of s i m i l a r i t y between p l o t s i s comparatively l e s s f o r x e r i c , h y d r i c and h y g r i c p l o t s than those i n the intermediary mesic p o s i t i o n s as i n d i c a t e d i n the dendrogram (Figure 9 ). Taking a l l p l o t s i n t o account the c o e f f i c i e n t of s i m i l a r i t y between i n d i v i d u a l p l o t s ranges from 21-73 percent. In d e r i v i n g a s s o c i a t i o n s or higher u n i t s l e v e l s of s i m i l a r i t y must be s e l e c t -ed. West (1966) has defined such l e v e l s as coenons. Within each coenon there may be s e v e r a l d i f f e r e n t but reco g n i z a b l e v e g e t a t i o n u n i t s . A h o r i z o n t a l l i n e drawn across the dendrogram at the 30 percent l e v e l o f s i m i l a r i t y creates twenty-one 30-coenons ( f o l l o w i n g Sokal and Sneath, 1964) . At t h i s l e v e l vege-t a t i o n u n i t s may be recognized f o r a l l but the s e m i - t e r r e s t r i a l (chionophobous h a b i t a t s . The reason f o r t h i s w i l l be discussed l a t e r . At lower l e v e l s o f s i m i l a r i t y s u b a s s o c i a t i o n s and a s s o c i a t i o n s are grouped together and fewer u n i t s are present i n each successive coenon. The moderately drained or mesic h a b i t a t s on the slopes dominated by Betula glandulosa, Ledum deeumbens and Eriophorum vaginatum, i n c l u d e a t o t a l o 61 p l o t s (3 a s s o c i a t i o n s ) , are j o i n e d together at the 28 percent l e v e l of s i m i l a r i t y . The w e l l drained or x e r i c s i t e s are c h a r a c t e r i z e d by 22 p l o t s (2 a s s o c i a t i o n s ) and are j o i n e d at the 24 percent l e v e l of s i m i l a r i t y . The poorl y drained s i t e s i n c l u d e a t o t a l o f 28 p l o t s (6 a s s o c i a t i o n s ) and are as-s o c i a t e d at the 6 percent l e v e l . The snow bed or chionophilous h a b i t a t s domi-nated by S a l i x chamissonis (14 p l o t s ) have a c o e f f i c i e n t o f s i m i l a r i t y of 37 percent, the very l a t e snow bed ( S a l i x pseudopolaris) w i t h f i v e p l o t s are j o i n e d at the 31 percent l e v e l of s i m i l a r i t y . However, a l l three a s s o c i a t i o n s are j o i n e d at only the 8 percent l e v e l . I t may be concluded that the mesic vege t a t i o n i s comparatively more s i m i l a r and covers a wider area than the more t r a n s i t i o n a l or unstable and l e s s extensive v e g e t a t i o n types found on the more Figure 9 Dendrogram of p l o t s i m i l a r i t i e s RELATIVE LEVEL OF SIMILARITY O i— O ro O CJ O - r -o O < C > r TJ r O H o O — 4 — o CD 9 O — i — 911 091 6SI 2 T ^ • ZP • 8S ^ SOI g -OS R-• 16 g •S6 I 6£ a t^ 8 c 38 a 06 ES" 18 OOl 08 \ 9Si ISI f 6 \ 821 617 es se LZ\ SSI ESI LA b C8 Ocl se x> Z.S C9 zei \ LP IS SSI cr 901 r> 9V esi 211 Z.9I Q - 181 P - 9Z.I - 6 T ^ - 621 - SSI Z -88 -611 - S9I - 6t7| - 921 - Ill * - 281 ? - IVI - SOI - SZ.I - v z r ^ - 291 - SVI - LS\ - (XI - 891 - 691 - 221 - Ot7l - 2171 - Efr I - 8VI - Z.17I - t79l - 26 601 \ on eoi 201 osi 09 \ 99 17Z. 66 t 7 9 \ II u> LL\ 71 VZ\ L<d LZ </> -1 12 6S 69 frS OV LZ VZ cr 1 2S <<> 8EI < 081 817 OEI \L Z6 • 9/L • 92 • Z.I • 98 • 191 • IOL - 6CI 2 V&fi.. APPENDIX I I SUMMARY OF DAILY MAXIMUM - MINIMUM TEMPERATURE AND RELATIVE HUMIDITY DATA AT GROUND LEVEL FOR CANOE LAKE MICROCLIMATIC STATIONS. JULY AND AUGUST 1966 ( ° F and %) JULY S t a t i o n 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 , Max. Temp.. . . 78 50 80 62 66 72 63 62 61 61 44 34 32 52 48 47 46 -44 60 48 77 47 76 53 70 56 69 60 48 49 77 56 73 73 57 34 47 32 57 38 71 48 64 66 48 46 46 48 42 30 32 28 44 29 37 32 58 31 62 44 64 44 R H M A X' Mi n . 68 .38 88 100 100 76 100 100 100 100 .34 49 43 34 55 61 100 40 100 58 97 33 80 44 77 42 76 97 40 47 69 47 72 98 45 52 98 64 97 66 80 37 87 100 100 98 62 59 83 71 96 100 90 58 98 87 98 44 74 51 75 44 2 T Max. T e m p * M 1 n „ 78 56 76 61 65 69 60 61 56 60 44 39 31 43 46 40 44 43 60 45 76 39 77 44 68 51 69 71 45 40 76 45 72 75 56 35 48 34 57 36 73 45 65 67 50 48 47 48 43 31 57 29 ?8 35 41 33 60 25 61 35 64 36 ° M i n . 100 100 100 100 100 100 100 100 100 100 100 50 57 75 69 61 79 83 100 73 79 56 92 66 92 69 100 100 65 64 94 62 87 100 60 68 100 100 100 100 100 100 100 100 82 81 54 80 64 92 82 87 96 100 100 71 93 61 98 100 74 72 3 T Max. l e m p . M . M i n . 60 41 58 45 74 42 74 52 64 54 -75 73 72 57 37 53 36 62 38 73 47 64 49 47 36 47 36 60 28 65 39 67 37 * M i n . 100 60 92 36 86 43 80 42 98 100 41 41 80 58 85 100 55 66 95 76 95 72 95 58 90 80 67 96 78 94 56 97 67 95 66 4 , Max. T e m p " M l n . 76 54 78 62 68 74 63 63 54 62 46 33 31 46 47 42 43 42 58 44 75 40 80 50 71 51 70 71 45 42 74 49 75 77 56 36 50 35 59 38 75 47 70 69 50 49 48 49 43 31 37 29 48 31 47 36 66 30 69 47 72 44 p u M a * ° l \ . n . u . M i n . 100 35 98 100 100 100 100 100 100 100 100 100 31 54 40 31 53 63 100 49 48 26 100 34 71 36 78 100 35 40 66 33 71 100 32 40 100 100 100 62 57 23 93 100 100 100 100 48 42 76 63 85 90 49 100 100 71 29 72 38 89 42 5 T Max. M i n . 80 64 68 75 68 64 56 64 50 37 33 43 50 52 49 47 60 50 77 38 78 52 71 58 70 72 49 39 78 43 76 77 54 37 52 36 61 38 76 42 70 72 53 52 50 50 43 32 43 32 51 34 42 36 65 26 67 38 68 37 R H M A X-M i n . 75 100 100 100 100 100 100 100 29 58 45 33 55 63 89 48 93 100 51 28 94 38 97 38 68 100 38 38 98 35 65 100 34 42 91 53 95 53 85 100 988 986 991 26 50 38 64 54 95 68 70 46 91 68 98 46 90 68 96 34 6 T Max. M i n . 72 56 57 60 57 53 49 62 47 36 31 39 45 39 42 42 62 53 73 48 76 57 72 62 71 74 55 49 72 59 70 68 56 42 51 40 58 42 68 46 65 67 54 49 52 52 49 37 42 35 49 36 42 40 58 30 62 39 62 39 p u M a x < > t\. r l o u . Mi n . 100 54 92 57 98 48 100 100 40 39 76 100 38 50 98 54 98 100 37 57 100 100 100 100 100 100 100 100 76 38 58 60 85 68 100 70 98 86 100 100 100 56 72 70 S t a t i o n SUMMARY OF DAILY MAXIMUM - MINIMUM TEMPERATURE AND RELATIVE HUMIDITY DATA AT LEVEL FOR CANOE LAKE MICROCLIMATIC STATIONS. JULY AND AUGUST 1966 (°F and I) JULY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Max. 78 65 66 73 66 63 55 64 59 78 80 72 71 73 80 '76 75 52 60 76 69 73 52 50 41 50 43 64 68 69 'Mi n . 50 36 33 42 51 40 48 47 45 37 52 54 50 40 44 54 38 38 39 42 50 49 45 34 32 34 37 27 38 38 Max. 68 100 100 100 96 100 100 100 89 92 85 85 78 100 94 77 100 93 94 95 89 94 100 100 93 89 91 98 94 96 ' M i n , 26 47 36 25 49 52 79 40 53 30 37 38 36 35 34 37 43 53 52 28 49 50 66 57 68 49 74 35 42 41 Max. 76 65 66 71 66 59 52 64 63 84 85 80 78 81 81 84 74 54 64 83 72 75 52 53 45 53 43 68 71 70 'Mi n . 47 33 33 46 47 41 45 43 46 42 51 54 46 46 50 54 35 35 38 44 47 48 42 31 30 32 35 28 44 42 Max. 70 100 100 90 96 100 90 98 94 95 88 85 85 96 90 95 100 95 96 93 95 100 95 96 95 94 92 95 79 88 ' M i n . 26 44 36 33 44 55 81 40 49 45 52 . J l 50 50 52 50 61 69 66 46 50 65 77 70 79 65 77 48 54 56 Max. 56 77 77. 71 69 70 79 77 76 50 57 36 66 68 52 49 37 48 43 64 65 68 ' M i n . 40 32 44 45 44 33 38 47 34 34 35 36 45 42 42 30 29 32 31 22 34. 33 Max. 92 96 90 90 91 100 92 78 100 86 92 94 82 95 95 92 90 67 86 94 91 92 'Mi n . 42 22 30 30 30 30 J * . 26 33 44 45 16 42 27 57 46 77 49 52 27 40 37 AUGUST Max. 62 58 63 67 58 62 60 46 35 31 44 46 50 51 50 55 58 57 54 57 58 59 60 61 46 46 58 ' M i n . 46 45 46 46 42 40 44 30 29 28 26 31 31 32 34 40 45 42 40 41 40 44 46 31 32 35 43 Max. 60 95 100 98 100 95 98 100 95 95 95 88 93 98 95 65 80 98 98 100 80 57 81 98 97 94 78 ' M i n . 41 54 60 43 62 57 57 68 95 52 62 55 41 48 48 , 4 0 47 46 55 62 40 45 49 65 52 75 46 Max.- 62 60 61 69 61 61 61 48 35 34 50 49 52 52 50 61 60 60 55 59 59 63 61 54 50 46 62 68 'Mi n . 40 41 37 41 41 41 39 30 29 28 25 30 27 25 34 33 44 38 38 38 40 40 44 32 30 30 34 37 Max. 84 100 100 100 100 100 100 100 100 100 100 98 100 100 100 97 86 100 100 100 92 88 98 100 100 100 995 95 ' M i n . 62 80 79 61 72 75 76 83 100 66 71 70 68 67 69 60 66 64 80 62 57 62 67 82 66 92 62 57 Max. 64 64 64 70 62 65 64 52 39 34 50 49 57 55 53 60 58 58 55 60 58 61 58 51 48 47 60 65 ' M i n . 38 43 37 42 44 42 40 32 81 30 22 31 27 26 31 31 44 42 38 39 41 38 43 41 32 29 36 35 Max. 93 98 96 96 97 96 96 96 94 94 100 90 98 97 96 93 77 100 100 97 92 100 100 100 ' M i n . 57 74 72 55 67 69 69 75 92 92 67 67 64 6 2 ' 64 58 60 62 77 71 54 66 82 62 Temp. R . H . Temp. R . H . Temp, R.H, R.H, Temp, R . H . SUMMARY OB DAILY MAXIMUM - MINIMUM TEMPERATURE AND RELATIVE HUMIDITY DATA AT LAKE M AUgUSf LEVEL FOR CANOE MICROCLIMATIC STATIONS. JULY AND AUGUST 1966 (°F and %) S t a t i o n T Max. T 3 m p ' M i n . , Max. 66 T s m p ° M i n , .41 D u Max. 87 ° ' M i n . 34 T Max. 61 T e m p ° M J n . 40 D u Max. 98 K ° H l i n . ' 57 T Max, 68 T e m p " M n v - 40 Pj_Jl1ax.. 68 T Max. T e m p ° M r n . P ^  rfl3Xo' " M i n . , Max. l e m p . M . Mi n. R . H . M a x ° ' M i n . 2 3 4 5 6 7 . 8 _ _ 9 _ 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 66 68 77 66 69 69 53 38 37 50 52 60 60 58 65 66 65 60 64 64 6? 64 57 53 49 63 45 42 47 45 43 47 32 31 31 27 35 32 31 35 39 50 42 41 43 44 42 48 43 35 33 39 100 100 100 100 100. 100 100 100 100 98 88 98 100 100 77 63 100 100 100 88 53 50 28 57 45 32 51 100 91 48 42 36 32 33 27 33 33 57 48 26 64 66 75 64. 66 6 J 52 40. 52 53 5.6 56 56 64 63 63 58 61 65 66 63 56 53 49 63 66 44 40 40 45" 44. 40 42 32 32 28 31 26 24 34 88 48 38 34 35 44. 38 45 40 33 33 35 33 100 100 98 .98 96 96 97 95 90 88 85 96 98 95 91 73 100 98 16 60 66 100 100 100 100 96 96 55 52 32 46 44 45 52 66 71 45 42 38 37 38 30 38 37 53 50 32 36 42 55 71 74 37 42 58 60 B8 59 63 60 §6 39 38 48 SQ 50 50 : 52 50 59 58 55 55 57 61 59 56 49 48 60 62 42 41 40 44 44 41 35- 35 32 32 34 29 26 34 32 43 41 36 36 45 38 42 42 35 35 36 34 98 98 100 98 98 100 96 98 97 92 87 97 98 96 100 98 96 100 98 92 95 98 100 100 100 100 71 74 72 82 75 71 75 88 85 65 69 60 66 62 60 53 57 75 92 52 53 57 70 57 85 66 65 66 71 63 67 66 53 39 39 51 52 56 57 56 66 64 60 60 62 65 66 63 56 53 50. 62 64 43 37 39 46 44 40 34 33 30 28 34 25 24 33 30 43 41 35 44 42 38 40 37 36 33 35 34 95 100 98 94. 97 96 95 96 100 98 94: 92 96 94 94 82 98 97 90 72 71 100 98 97 96 95 94 - 4 8 49 40 50 44 43 53 65 49 52 44 40 34 35 30 38 43 53 37 31 37 44 55 40 70 50 47 70 68 71 58 71 70 50 38 38 53 54 57 59 60 63 71 62 59 60 66 71 63 56 55 49 66 64 44 40 44 44 42 44 32 30 30 25 33 29 28 34 36 44 40 40 40 40 40 44 34 33 31 36 44 96 96 94 93 92 94 96 98 92 86 93 95 91 77 80 94 94 93 87 73 96 94 95 93 94 93 93 58 60 58 76 56 65 83 77 61 56 54 48 48 48 47 54 65 65 46 58 57 70 57 79 52 55 62 62 64 71 64 65 64 49 37 34 50 52 56 56 54 65 65 60 59 60 65 68 64 58 53 50 65 63 40 34 32 42 39 34 31 28 27 22 30 20 22 28 26 37 38 30 34 38 32 38 34 30 30 32 35 90 100 90 91 96 93 90 88 86 82 78 92 90 94 93 85 94 100 92 72 86 98 92 95 96 92 92 45 44 32 39 39 40 48 70 58 39 37 . 33 29 31 31 27 31 47 28 20 27 34 47 33 63 28 22 APPENDIX I I I (CONTINUED) 7. S t r a t a Coverage (%) r e f e r s to the area covered by the i n d i c a t e d s t r a t a as a percentage of the p l o t area. S t r a t a are defined: B l a y e r (shrub l a y e r ) , C l a y e r (herb l a y e r ) , D l a y e r (ground surface l a y e r , i n c l u d i n g mosses and l i c h e n s ) . The symbol Dr r e f e r s to coverage o f l i c h e n s on rocks. 8. P l o t coverage (!) r e f e r s to the area covered by water or rock as a per-centage o f the p l o t area. 9. Drainage i s an estimate determined from observation and r e f e r s to the moisture c o n d i t i o n of the p l o t s p r i o r to the f i r s t autumn s n o w f a l l . 10. Hygrotope c l a s s e s r e f e r to the moisture regime s t a t u s o f the p l o t s s t u d i e d i n the Low A r c t i c S u b a l p i n e / F o o t h i l l Zone. They are r e l a t e d to moisture c o n d i t i o n s during the snow f r e e p e r i o d and not c o n d i t i o n s immediately f o l l o w -in g snow melt. The c l a s s e s are r e l a t e d to topography, s o i l p r o f i l e c h a r a c t e r i s t i c s , t h i c k n e s s of the a c t i v e l a y e r , drainage and l e v e l s o f water-t a b l e i n the p r o f i l e i f present. D e s c r i p t i o n s o f the s i x c l a s s e s used are as f o l l o w s : Hygrotope c l a s s D e s c r i p t i o n X e r i c Ridge tops and escarpments. A c t i v e l a y e r very.deep, although a c t u a l s o i l l a y e r s are shallow and w e l l drained. Sub-xeric Upper exposed slopes. S o i l s w e l l drained w i t h some seepage i n l a t e s p r i n g . A c t i v e l a y e r deep. Medium t e x t u r e d s o i l s with good drainage, seepage i n lower part o f p r o f i l e during the summer. Depth of a c t i v e l a y e r v a r i a b l e , deeper under hummocks than depressions. Snow bed h a b i t a t s w i t h moderately drained s o i l s . G l e y i n g i s evident i n the s o i l p r o f i l e and seepage occurs. A c t i v e l a y e r always deep. Moderately to i m p e r f e c t l y drained s o i l s on lower slopes. Gleying i s evident i n moderately drained s o i l s . Water below surface during l a t t e r part o f summer. Seepage always present. A c t i v e l a y e r very shallow to shallow. S o i l s w i t h impeded drainage. A c t i v e l a y e r very shallow. Water l e v e l may be a t , or near, the surface during the summer. 11. Chemical analyses Chemical p r o p e r t i e s present i n the t a b l e s represent average values f o r the organi c , organic - mineral and mineral l a y e r s . The number of samples f o r each l a y e r was- determined on the b a s i s of percent organic matter present i n each sample ( i . e . organic l a y e r over 32 percent, organic - mineral layer, between 2 and 35 percent and mineral l a y e r from 0.0 to 10 p e r c e n t ) . Mesic Moist Hygric Hydric APPENDIX I I I 4 APPENDIX I I I EXPLANATORY NOTES FOR VEGETATION AND ENVIRONMENT SYNTHESIS TABLES A. Vegetation Tables (Numbers 2a - 15a) 1. Nomenclature of the u n i t s f o l l o w s standard p h y t o s o c i o l o g i c a l p r a c t i c e . P h y t o s o c i o l o g i c a l designations are modified from the gene r i c name of the species and i n some cases the s p e c i f i c name appears i n the g e n i t i v e case. Orders: A l l i a n c e s : A s s o c i a t i o n s : Subassociations: V a r i a t i o n s : - t a l i a - i o n -etum -etosum -os urn Species r a t i n g s f o r i n d i v i d u a l p l o t s f o l l o w the Domin-Krajina s c a l e s (see K r a j i n a , 1935) f o r species s i g n i f i c a n c e a.nd Lambert f o r s o c i a b i l i t y and are given by twc f i g u r e s ( i . e . 3.1) Species s i g n i f i c a n c e (combined s c a l e f o r abundance and dominance) + Very s p a r s e l y present, dominance very small 1 S p arsely present, dominance small 2 Very s c a t t e r e d , dominance small 3 Sc a t t e r e d to p l e n t i f u l 4 Often, dominance 1/20 to 1/10 of p l o t 5 Often, dominance 1/5 to 1/4 of p l o t 6 Any number of i n d i v i d u a l s , dominance 1/4 to 1/3 7 Any number o f i n d i v i d u a l s , dominance 1/3 to 1/2 8 Any number o f i n d i v i d u a l s , dominance 1/2 to 3/4 9 Any number o f i n d i v i d u a l s , dominance over 3/4 10 Any number of i n d i v i d u a l s , dominance 100% of p l o t S o c i a b i l i t y + Growing s i n g l y 1 Grouped or t u f t e d , up to 16 sq. m 2 Group, 1/3 to 2/3 sq. m 3 Group, 1 to 2 sq. m 4 Group, 5 to 20 sq. m 5 Group, 25 to 50 sq. m 3. P l o t s are arranged h o r i z o n t a l l y across the t a b l e by i n c r e a s i n g e l e v a t i o n from l e f t to r i g h t . 4. Species are arranged v e r t i c a l l y f o r each t a b l e as f o l l o w s : a) by s t r a t a B l a y e r B^ Shrubs over 6 feet i n height 1&2 Shrubs 6 inches to 6 feet i n height C l a y e r Small.woody p l a n t s l e s s than 6 inches i n height and a l l herbaceous p l a n t s D l a y e r Bryophytes, l i c h e n s and a l l s e e d l i n g s . APPENDIX I I I (CONTINUED) b) by decreasing presence value, w i t h i n s t r a t a c) by decreasing cover value w i t h i n s t r a t a 5. Constancy and average cover value r a t i n g s are l i s t e d i n the s y n t h e s i s t a b l e s f o r a l l species except those l i s t e d as "Sporadic s p e c i e s " . For species oc-c u r r i n g i n two, or more, s t r a t a , only one r a t i n g was made. Average cover values f o r i n d i v i d u a l species were, determined by t o t a l l i n g t h e i r species s i g n i f i c a n c e values and d i v i d i n g by the number of p l o t s sampled i n the as-s o c i a t i o n . Constancy was r a t e d on a l i n e a r s c a l e of 5 c l a s s e s as i n d i c a t e d below. Species o c c u r r i n g Constancy s c a l e on % of p l o t s of 5 c l a s s e s 81-100 V 61- 80 IV 41-60 I I I 21- 40 I I 1-20 I B. Environment Tables (Numbers 2b - 15b) Nomenclature of the u n i t s and o r g a n i z a t i o n of the p l o t s w i t h i n any ecosystematic u n i t i s described i n note A no. 1. 1. L o c a l i t y i s designated as f o l l o w s : Richardson Mountains, Northwest T e r r i t o r i e s Canoe Lake CL Divided Lake DL B r i t i s h Mountains, Yukon T e r r i t o r y Trout Lake TL 2. Land form describes the o l d land surface topography ( i . e . depression, r i d g e top, exposed s l o p e , r i v e r bank, o l d drainage pathway or lake edge). 3. R e l i e f : P r o f i l e describes the s u r f a c e shape of the sample p l o t ( i . e . concave, convex, s t r a i g h t , f l a t or hummocky). 4. Exposure (°) r e f e r s to the topographic p o s i t i o n o f the p l o t i n r e l a t i o n to a p a r t i c u l a r c a r d i n a l p o i n t ( i . e . 90 - f a c i n g due e a s t ) . 5. Slope gradient (°) r e f e r s to the average i n c l i n a t i o n of the ground s u r f a c e from the h o r i z o n t a l plane. 6. Snow du r a t i o n (months) i s an estimate determined from observations and r e f e r s to the length of time between snowfall remaining i n the autumn and complete v melt from the p l o t surface i n l a t e s p r i n g or at any time during the summer. x e r i c or h y d r i c ends of the g r a d i e n t . Because of the large number of p l o t s used i n the c l u s t e r a n a l y s i s i t i s to be expected that not a l l would be n e a t l y c l u s t e r e d i n t o a s s o c i a t e d u n i t s . A p l o t which i s a component of one c l u s t e r may be i n c l u d e d with an adjacent c l u s t e r . While the i n d i v i d u a l p l o t may have the same dominant species as the. c l u s t e r i t i s a r b i t r a r i l y grouped w i t h , i t s degree of s i m i l a r i t y w i t h a l l the p l o t s i n t h a t c l u s t e r i s l e s s than with those i t i s o b j e c t i v e l y grouped w i t h . Such an example may be found with p l o t s 163 and 166. Both are c l u s t e r e d with V a c c i n i o - Betuletum glandulosae f r u t i c u l o s u m but s u b j e c t i v e l y a s s o c i a t e d w i t h Betulo - Ledetum decumbentis cassiopeetosum tetragonae on the b a s i s of t h e i r dominant species - Cassiope tetragona. Due to the complex, nature of the environmental factors.encountered i n the A r c t i c , i t appears impossible to a t t a i n a smooth bel l - s h a p e d curve f o r i n d i v i d -u a l species d i s t r i b u t i o n . Whereas o r d i n a t i o n i l l u s t r a t e s only gradients such a dendrogram as shown here produces s y n e c o l o g i c a l u n i t s , on a species presence/ absence b a s i s o n l y , that are necessary f o r p r a c t i c a l s y n e c o l o g i c a l programs. A d e t a i l e d d i s c u s s i o n of the v e g e t a t i o n u n i t s as r e l a t e d t o environmental phenomena i s presented i n the f o l l o w i n g chapters. DESCRIPTION OF VEGETATION UNITS Synthesis t a b l e s p r o v i d i n g f u l l d e t a i l s of the vegetation-environmental r e l a t i o n s h i p s are presented f o r each a s s o c i a t i o n , and where a p p l i c a b l e , sub-a s s o c i a t i o n s and v a r i a t i o n s . L i s t e d i n Appendix I are 419 taxa, i n c l u d i n g v a s c u l a r p l a n t s , bryophytes and l i c h e n s . The major f l o r i s t i c and environ-mental features which c h a r a c t e r i z e these u n i t s are o u t l i n e d i n t h i s s e c t i o n . The descriptions., are presented so that r e l a t i o n s h i p s between r e l a t e d u n i t s w i l l be evident. A. Chionophobous p l a n t communities with snow d u r a t i o n averaging nine months or l e s s . T e r r e s t r i a l p l a n t communties 1. Salicetum phlebophyllae Table 2 (a) f7 (b) (Figure 10) S a l i x p h l e b o p h y l l a i s the dominant species i n p l o t s on the exposed w e l l drained upper l i m i t s of ridges and felsenmeer slopes where ve g e t a t i o n i s very sparse. These s i t e s are on predominantly north - northwest f a c i n g slopes. They range i n e l e v a t i o n from 1450-2025 f t at Canoe Lake and are present at the 1150 f t l e v e l at Trout Lake. Spetzman (1959) i n h i s s t u d i e s on the Alaskan Slope had found S^. p h l e b o p h y l l a to be common along the mountain f r o n t between 2000-4000 f t . There i s l i t t l e snow accumulation because of the exposed p o s i -t i o n so that snow p e r s i s t a n c e i n t h i s a s s o c i a t i o n i s g e n e r a l l y s h o r t , seldom more than 7 1/2 months per year. Such areas are w e l l drained and t h e i r s o i l s are f r e e from f r o s t i n the summer, and because of t h e i r convex p r o f i l e are w i t h -out seepage water. The s o i l s are g e n e r a l l y shallow, although the thickness of the a c t i v e l a y e r i s g r e a t l y increased by the coarseness of the underlying i c e s h a t t e r e d rock m a t e r i a l s . Exposed rock i s estimated to cover between 30-80 percent of the surface area. P h y s i c a l weathering i s important i n c o n t r a s t to chemical weathering. Mechanical breakdown of parent m a t e r i a l s i s by f r o s t cleavage during the freeze-thaw c y c l e s and wind a c t i o n . These two. f a c t o r s are r e s p o n s i b l e f o r r e s t r i c t i n g c o l o n i z a t i o n of a d d i t i o n a l m i c r o h a b i t a t s . Table No. 2. b Salicetum phlebophyllae Plot No. 62 Plot size (m2) 16 Date Analyzed 13/7 1965 PLOT DATA Locality TL Elevation 1150 15 13 4 1 16 16 16 16 15/6 14/6 10/6 9/6 1965 1965 1965 1965 CL CL CL CL U50 1550 1880 2025 PHYSIOGRAPHY Land form Ridge side Relief: P r o f i l e Cvx Exposure (°) 200 Slope gradient 8 Ridge Exposed Ridge Ridge top slope side side F l a t ....Convex.... Stg Total 0 270 270 0 20 37 14 CLIMATE Snow duration 7-g- months STRATA COVERAGE {%) Bi layer B ? layer C layer 40 20 20 35 25 D layer Moss 5 5 2 5 25 Lichen 15 20 23 30 15 Dr 15 40 60 15 15 Total D 35 65 85 50 55 PLOT COVERAGE {%) by rock 35 80 95 40 30 by water SOIL Drainage Hygrotope Depth of active layer .Well drained ....Xeric .Undetermined CHEMICAL ANALYSIS No.of samples Organic -Mineral layer Mineral layer 1 2 1 2 2 0M 2 0 . 2.5 3. 1 4.1 3.0 M% 09 .07 14 .17 .07 C/N 12.9 20.7 12. 8 14-0 24.9 P ppm 5 5 8 6 10 Na 42 .72 85 72 1.07 K 1 .11 14 33 .18 Ca 1 1 .9 1. 1 1 9 .9 Mg 1 - 1 9 .3 CEC 11 8 46.1 19. 3 17 3 7.4 pH 4 7 4.6 4- 8 5 1 4.3 OM .2 1 5 .9 N% • 05 08 .04 C/N 2.3 10 9 13.1 P ppm 6 6 13 Na .81 3 .83 K .07 17 .09 Ca .9 7 .9 Mg - 3 -CEC 17.3 11 8 7.4 pH 5.1 4-9 4-9 Table Ho. 2 0 Salicetum phlebophyllae Number of Plots Plot No. Plot size (m ) Elevation ( f t ) 1 2 3 4 5 62 15 13 A 1 16 16 16 16 16 1150 1450 1550 1800 2025 Avg. C layer Constancy Cover 1 Salix phlebophylla 4.2 4-2 4-2 6.3 A-2 V A-A 2 Hierochloe alpina 1.1 2.1 2.1 1.1 1.1 V 1.4 3 Arenaria, arctica +.+ 1.1- 2.1 1.1 1.1 V 1.2 4 Oxytropis nigrescens 3.1 2.1 - + .+ 3.2 IV 1.8 5 Dryas octopetala 4-2 1.1 - 1.1 1.1 IV 1.6 6 Carex podocarpa - 1.1 3.1 1.1 1.1 IV 1.2 7 Antennaria neoalaskana 2.1 + .+ - 1.1 1.1 IV 1.0 8 Douglasia arctica 1.1 1.1 1.1 - 2.1 IV 1 .0 9 Selaginella s i b i r i c a 1.1 + .+ 1.1 - 1.1 IV .8 10 Arctostaphylos alpina - 1.1 - 1.1 + .+ III .6 11 Artemisia arctica - 1.1 - - 1.1 II • A 12 Luzula confusa - - - 1.1 + .+ II • A 13 Smelowskia oalycina + .+ 1.1 - - - II • A D layer (Bryophytes) 14 Gymnomitrion corallioides + .1 1.1 - 2.1 A-2 IV 1.6 15 Polytrichum piliferum 2.1 2.2 +.+ - - III 1.0 16 Polytrichum juniperinum - - 1.1 - 5-2 II 1.2 17 Rhacoraitrium lanuginosum 1.1 - - 2.2 - II .6 (Lichenes) 18 Cornicularia divergens 2.1 3.1 4-2 2.1 3.1 V 2.8 19 Alectoria miniscula 2.1 2.1 + .+ 1.1 1.1 V 1.4 20 Parmelia separata 1.1 2.1 2.1 1.1 1.1 V 1.4 21 Parmelia omphalodes +.+ 1.1 1.1 1.1 1.1 V 1.0 22 Sphaerophorus globosus 1.1 + .+ 1.1 + .+ 1.1 V 1.0 23 Rhizocarpon geographicum 1.1 2.1 3-1 4-1 - IV 2.0 24 Haematomma lapponicum 1.1 2.1 A-2 - 2.1 IV 1.8 25 Cetraria n i v a l i s 1.1 1.1 2.1 2.1 - IV 1.2 26 Cetraria chrysantha 1.1 1.1 - 2.1 + .+ IV 1.0 27 Alectoria ochroleuca 2.1 1.1 1.1 + .+ - IV 1.0 28 Thamnolia vermicularis - 1.1 + .+ +.+ 1.1 IV .8 29 Umbilicaria proboscidea - A- + 5.+ + .+ - III 2.0 30 Alectoria nigricans - 3.1 3.2 - 3.1 III 1.8 31 Umbilicaria hyperborea 1 •+ - 2.+ - A.+ I I I 1.4 32 Ochrolechia f r i g i d a + .+ 2.1 - 3.2 - III 1.2 33 Cetraria nigricascens - 2.1 1.1 2.1 - III 1 .0 34- Pertusaria coriacea - 1.1 - 3.2 + .+ III 1.0 35 Cetraria cucullata 1.1 - - 2.1 + .+ I I I .8 36 Hypogymnia subobscura 1.1 + .+ - - + .+ I I I .6 37 Parmelia alpicola - - A-2 1.1 - II 1.0 38 Parmelia stygia + .+ - 1.1 - - II • A 39 Cetraria scholanderi - 1.1 1.1 - - II • A 40 Lecidea flavocaerulescens - - 1.1 1.1 - II • A TOTAL SPECIES (incl.sporadics) 33 38 A2 37 29 Sporadic species C layer 41 Diapensia lapponica 42 Vaccinium vitis-idaea 43 Ledum decumbens 44 Kobresia myosuroides 45 Salix brachycarpa 46 Saxifraga tricuspidata 47 Potentilla vahliana 48 Draba n i v a l i s 49 Lupinus arcticus 50 Poa arctica 51 Tofieldia coccinea D layer (Bryophytes) 52 Encalypta .rhaptocarpa 53 Pogonatum capillare 54 Hypnum cupressiforme 55 Pohlia nutans 4(1-1) D layer (Lichenes) 56 Cetraria t i l e s i i 1(1.1) 4(+.+ ) 57 Cetraria hepatizon 4(1 .1 ) 4(+.+ ) 58 Toninia cumulata 4(1 .1 ) 15(2.1) 59 Pertusaria panyrga 4(+.+ ) 15(1.1) 60 Cladonia chlorophaea 4(+.+ ) 15(+.+ ) 61 Lecanora polytropa 4(+.+ ) 15(1.1) 62 Cladonia mitis 13(1.1) 62(+.+ ) 63 Buellia atrata 13(1.1) 62(+.+ ) 64 Lecidea lapioida 13(1 .1) 62(1.1) 65 Parmelia almquistii 13(1.1) 62(1.1) 66 Cladonia pleurota 13(+.+ ) •67 Lecidea atromarginata 15(5.2) 1(1 .1 ) 68 Stereocaulon rivulorum 62(1.1) 4(+.+ ) 69 Solorina crocea 62(1.1) 13(1.1) 15(+.+ ) Organic matter i s present only under the v e g e t a t i v e mats. In comparison with a l ] other communities the Salicetum phlebophyllae develops on s i t e s w i t h only the slightest p r o t e c t i o n from d e s i c c a t i n g winds. These s i t e s are formed by movements of surface rock and m a t e r i a l s due to freeze-thaw c y c l e s . While no non-sorted polygons are recognized, there i s a s o r t i n g o f s u b s t r a t e , l e a v i n g coarse m a t e r i a l s exposed and the f i n e r m a t e r i a l covered with v e g e t a t i o n . Due to the exposed p o s i t i o n of the community the m a j o r i t y of the species tend to have a p r o s t r a t e form. The v e g e t a t i o n i s domi-nated by woody species t h a t are c h a r a c t e r i z e d by t h e i r a b i l i t y to form mats. These mats, however, never form a closed system. As much as 40 percent of each mat c o n s i s t s of dead leaves, twigs and stems. Figure 10. Depression on exposed r i d g e (1500 f t ) w i t h A r c t i c Hamada west side of Canoe Lake, dominated by S a l i x p h l e b o p h y l l a w i t h s c a t t e r e d B e t u l a glandulosa. Sandstone fragmented by frceze-thaw a c t i o n w i t h evidence of f r o s t heav-in g i n foreground. (Photo by K r a j i n a ) 43 Flowering occurs e a r l i e r i n t h i s a s s o c i a t i o n than i n any other, and has g e n e r a l l y been completed before species on the lower slopes have s t a r t e d to bud. P o r s i l d (1951) and others have described the phenomena of the a r c t i c p l a n t s being frozen and covered w i t h i c e c r y s t a l s i n the e a r l y morning and thawing a few hours l a t e r and showing no apparent s i g n of f r o s t damage. Asso c i a t e d w i t h S a l i x p h l e b o p h y l l a but w i t h lower coverage values are such mat forming species as A r e n a r i a a r c t i c a , Oxytropis nigrescens, Douglasia a r c t i c a , S e l a g i n e l l a s i b i r i c a and s c a t t e r e d Dryas o c t o p e t a l a spp. a l a s k e n s i s . In more s h e l t e r e d p o s i t i o n s Hierochloe a l p i n a , Antennaria neoalaskana and Carex podocarpa are present, but w i t h very low coverage values. In the f i v e p l o t s r e p r e s e n t i n g t h i s community there are only three v a s c u l a r p l a n t s con-s t a n t l y present: S a l i x phiebophy. 11a, A r e n a r i a a r c t i c a and Hierochloe a l p i n a . An i n d i c a t i o n of the exposed p o s i t i o n of these p l o t s i s the presence c f the l i v e r w o r t Gymnomitrion c o r a l l i o i d e s . This species occurs only i n areas ex-posed to the wind and i s a s s o c i a t e d with Polytrichum p i l i f e r u m , P. juniperinurn and Rhacomitrium lanuginosum. The l i c h e n f l o r a i n t h i s a s s o c i a t i o n i s r i c h and has a high t o t a l percent cover value i n r e l a t i o n to the vascular and bryophyte f l o r a . Saxicolous species i n c l u d e A l e c t o r i a m i n i s c u l a , Parmelia separata, P. s t y g i a , Rhizocarpon  geographicum, Haematomma lapponica, U m b i l i c a r i a hyperborea, IJ. pjroboscidea, Lecidea f l a v o c a e r u l e s c e n s and _L. atromarginata. Species growing among the mats and mosses i n c l u d e C o r n i c u l a r i a divergens, C e t r a r i a c u c u l l a t a , C_. n i v a l i s , C_. chrysantha, Sphaerophorus globosus, Thamnolia v e r m i c u l a r i s , A l e c t o r i a ochroleuca and A. n i g r i c a n s . There are few species present on dead p l a n t m a t e r i a l and bare s o i l due to the i n s t a b i l i t y o f these s u b s t r a t e s . However, Ochrolechia f r i g i d a , P e r t u s a r i a c o r i a c e a , Hypogymnia subobscura and C e t r a r i a . n i g r i c a s c e n s are o c c a s i o n a l l y present. .. While there are few constant species i n t h i s a s s o c i a t i o n there appears to be no lack of species able to t o l e r a t e such adverse c o n d i t i o n s . Approximately s i x t y f i v e s p e c i e s , i n c l u d i n g v a s c u l a r p l a n t s , bryophytes and l i c h e n s , are present i n the Salicetum phlebophyllae. 2. Lupino - Dryadetum * a l a s k e n s i s Table 3(a) § (b) In c o n t r a s t to the exposed s p a r s e l y vegetated s i t e s discussed e a r l i e r are the s l i g h t l y more s h e l t e r e d Dryas dominated slopes. These f l o r i s t i c a l l y r i c h h a b i t a t s c o n t a i n a l a r g e r number of species and show more v a r i a t i o n than any other a s s o c i a t i o n i n the study r e g i o n . They are comparable to the Dryadetum i n Sweden ( G j a e r e v o l l and B r i n g e r , 1965) and the Dryas punctata - S a l i x r e t i c u l a t a i n Scotland (McVean, 1964). With a decrease i n exposure the amount of bare s o i l and rock i s reduced and v e g e t a t i o n becomes more compact. How-ever, snow cover i n w i n t e r i s s t i l l scanty so that the mat-forming species are c o n s t a n t l y being eroded by wind. The bare areas are g e n e r a l l y populated by such crustose l i c h e n as P e r t u s a r i a , Ochrolechia and Lecidea. Two s u b a s s o c i a t i o n s are d i s t i n g u i s h e d i n t h i s subalpine zone, the de-pauperaturn and the dryadeto - s a l i c e t o s u m r e t i c u l a t a e - glaucae. (a) dryadetosum * a l a s k e n s i s (depauperatum) (Figure 11) This s u b a s s o c i a t i o n i s c h a r a c t e r i z e d by s t r o n g l y a c i d s o i l s and i s found on very w e l l drained upper convex-straight felsenmeer slopes. In the Canoe Lake area a l l sampled p l o t s have we s t e r l y exposures and are between 1450-2000 f t e l e v a t i o n . At Trout Lake the one p l o t analyzed was at 600 f t w i t h an easterly-exposure. Slope gradients are a l l gentle between 5-14°. Exposed rock i n these p l o t s was estimated to cover between 10-30 percent of the surface area. Snow cover and accumulation i s s l i g h t l y g reater than the Salicetum phlebophyllae but not n e c e s s a r i l y 100 percent. Duration of snow i s estimated to be longer by approximately two weeks. Drainage during the annual thaw i s r a p i d with x e r i c c o n d i t i o n s p r e v a i l i n g throughout most of the summer. The s o i l p r o f i l e w h i l e g e n e r a l l y shallow does i n d i c a t e some genetic development. P h y s i c a l and chemical weathering are probably e q u a l l y important. Fine s o i l i s blown from the areas where i t i s exposed and not h e l d by plant cover. Rock fragments Table No. 3 b Lupino - Dryadetum i ;alasksnsis depauperatum I I dryado - salicetosum r e t i c u l a t a e - glaucae P l o t No. 73 137 25 2 77 61 10 . 136 9 146 • 133 178 7 104 Plot size (m^) Date Analyzed 25 ....50.... 15/7 11/7 19/6 9/6 15/7 12/7 13/6 11/7 13/6 14/7 10/7 12/8 11/6 11/8 1965 1966 1965 1965 1965 1965 1965 1966 1965 1966 1966 1966 1965 1965 PLOT DATA Lo c a l i t y TL CL CL CL TL TL CL CL CL CL CL CL CL CL Elevation ( f t ) 600 U 5 0 1650 2000 450 1100 1500 1500 1600 1600 1775 1900 2125 2390 PHYSIOGRAPHY Land form Depre- Ridge Stone Ridge River •-Sheltered-• Ridge Ridge ssion top str i p e side bank slope side top R e l i e f : P r o f i l e Cnv Stg ...Convex.... ...Straight.. Stg-Hum Stg F l a t ..Straight.. Exposure (°) 45 270 315 315 135 90 180 270 0 200 315 250 65 270 Slope gradient (°) 7 5 5 14 67 72 16 10 0 15 4 20 12 12 CLIMATE Snow duration STRATA COVERAGE ( %) C layer 65 70 70 85 100 100 60 80 55 95 85 90 95 65 D layer Moss 25 25 15 20 15 30 35 5 10 40 55 25 10 10 Lichen 15 15 40 20 10 15 45 30 25 25 20 55 20 25 Dr 10 15 12 2 1 10 15 2 1 5 10 10 PLOT COVERAGE (%) by rock 20 35 20 5 2 20 45 10 5 10 20 30 SOIL Drainage Hygrotope l e r i c Xeric Depth of s o i l 27 42 52 12 30 50 20 32 18 40 48 28 22 50 p r o f i l e (cm) CHEMICAL ANALYSIS No.of samples 1 1 1 NT 2 1 1 NT 1 Organic layer OM 67.7 64-9 70.9 62.3 79.5 92.3 63.5 1.61 1.8 1.1 • 91 1.08 1.9 2.31 C/N 24.4 20.9 36.9 39.7 40.8 31.5 15.9 P ppm 3 13 30 28 32 26 16 Na .54 .8 • 98 1.12 1.06 • 93 .8 K 1.06 • 47 • 73 1.51 • 49 1 .03 1.47 Ca 28.7 35.0 16.0 23.8 19.0 26.3 65.3 Mg 12.4 1.8 3-0 6 .1 20.3 3.6 9.0 CEC 183.0 117.0 36.9 67.4 95.8 132.7 83.8 PH 5-4 6.1 6.7 6.3 5.6 5.8 7.3 No.of samples 2 1 1 1 1 1 1 Organic - OM 9.1 13.0 22.8 33.2 16.6 23-3 18.0 Mineral layer t>% .08 .29 .78 • 93 .51 .79 .66 C/N 84.1 26.0 17.0 20.7 18.9 17.1 15.8 P ppm 6 10 37 13 13 24 8 Na • 42 .84 .72 • 52 .61 .74 .73 K .33 • 34 1.18 .63 .33 • 55 .23 Ca 9.2 8.4 15-4 24.2 10.3 20.0 19.2 Mg .9 .6 7.1 4.6 2.5 1.4 1.0 CEC 27.1 14.6 78.9 67 .1 74-9 46.0 38.4 pH • 4.8 6.2 6.3 5-5 5-3 7.0 6.8 No.of samples 1 2 1 2 1 1 2 1 2 2 ~ 1 1 4 Mineral layer OM 3.0 1.0 2.5 2.8 6.6 1.7 2.0 4.6 4.1 1.9 .0 3.8 5.6 N* .26 .03 .08 .1 .17 -03 .08 .17 .25 .08 .04 .16 .12 C/N 6.7 23.2 18.1 13.7 22.5 32.9 14-5 15.7 9-3 13.4 .0 63.8 29 .3 P ppm 3 8 10 11 5 6 12 6 13 10 5 5 12 Na .44 .84 .76 • 74 • 49 • 5 .77 .71 1.02 .76 .78 .72 .62 K .16 .1 .22 .16 • -15 .08 • 34 .41 .87 • 49 .41 .14 • 25 Ca 3.8 1.1 1.6 1.1 4.6 4.1 2.0 13.5 17.6 14-6 4.5 12.8 8.2 Mg .3 • 4 • 5 . • 3 1.4 1.4 • 5 • 5 3.8 12.8 .2 .8 1-4 CEC 15.2 9.6 16.3 5.7 30.0 19.7 14-4 23-4 37.9 33-5 13.6 18.1 26.9 PH 4.8 4.8 5.0 4.6 4-9 5.6 7.6 7.4 6.8 6.5 6 .1 7.6 5-8 Number of Plots Plot Ho. Plot size (*2) Elevation (ft) C_ laver 1 Dry as oc to petal a 2 Lupinus arcticus 3 Hierochloe alpina 4 Arenaria aro tic a 5 Polygonum vlviparum 6 Vaccinium uliginosun 7 Salix phlebophylla 8 Do tula glandulosa 9 Saxifraga tricuspidata 10 Oxytropis nigrescens 11 Luzula confusa 13 Carex podocarpa 13 Oxytropla maydalliana 14 Senecio fuacatus 15 Saxifraga rflflexa 16 Arctoataphylos alpina 17 Salix reticulata 18 Poa arctica 19 Antennaria neoalaskana 20 Kobresia myosuroidea 2' Anemone narcissiflora 22 Carex acirpoidea 23 Tofieldia coccinea 24 Bupleurura americanura 25 Poa glauca 26 Saxifraga punctata 27 Douglasia arctica 28 Artenisia arctica 29 Luzula nivalis 30 Salix glauca 31 Cas3iope tetragona 32 Rhododendron lapponicua 33 Arnica, alpina 34 Sllene acaulis 35 Saxifraga bronchialis 36 Pedicularia capitata 37 Papaver macounii 38 5axifraga flagellaria 39 Castilleja raupii 40 Astragalus urabellatus i l Arctagrostis l a t i f o l l a 42 Saxifraga hieracifolia 43 Cerastium beeringianura 44 Saxifraga hirculus 45 Salix arctica 46 Pedicularia lanata 47 Pedicularia arctica 48 Trisetum spicatujn 49 Polygonum bistorts 50 Stellaria longipea 51 Saussurea angustifolia 52 Carex capillaria 53 Stellaria clliatosepala 54 Campanula uniflora 55 Potentilla nivea 56 Festuca brachyphylla 57 Senecio rosodifolius 58 Senecio atropurpureua 59 Selaginella aibirica 60 Parrya nudlcaulis 61 Astragalus australis 62 Diapensia lapponica 63 Salix brachycarpa 64 Carex lugena 65 Lagotis glauca 66 Vaccinium vitis-idaea 67 Petasttos frigidua 68 Saxifraga davurica 69 Kobresia hyparborea 70 Arenaria roaaii D layer (Bryophytes) 71 Rhytidiura rugoaum 72 Aulacomnium turgidum 73 Dicranura fuscescens 74 Polytrichum juniperinum 75 Distichium capillacaum 76 Dicranura elongatura 77 Abietinella abietina 78 Ceratodon purpureus 79 Dicranum muhlenbackii 80 Polytrichum piliferum 81 Bryum sp. 82 Encalypta rhaptocarpa 83 Bryura pseudotriquetrum 84 Mnium orthorrhynchum 85 Pohlia sp. 86 Hylocomium splendens 87 Aulacomnium palustra 88 Dicranum angustum 89 Dicranum groenlandicun 90 Eurhynchlum pulchellura 91 Blepharostoma trichophyllura 92 Rhacomitrium lanuginosum 93 Tetraplodon urceolatus 94 Kyurella julacea (Lichenes) 95 Cetraria cucullata 96 Cetraria nivalis 97 Cetraria chrysantha 98 Thamnolia veraicularis 99 Hypogymnia subobscura 100 Pertusaria panyrga 101 Pertusaria coriacea 102 Cornicularia divergen3 103 Cetraria richardsonii 1Q4 Physcia musclgena 105 Rhizocarpon gaographicum 106 Nephroma expallidun 1D7 Cetraria ialandica 108 Peltigera canina 109 Ochrolachia upsalienaia 110 Alectoria nitidula 111 Lecanoro epibryon 112 Cetraria t i l e s l i 113 Alectoria ochroleuca 114 Stereocaulon alpinum 115 Parmelia oraphalodes 116 Leptoglum saturninum 117 Peltlgera aphthosa 118 Ochrolechia frigida 119 Sphaerophorus globosus 120 Dactylina arctica 121 Alectoria nigricans 122 Cornicularia aculeata 123 Alectoria miniscula 124 Umbilicaria hyperborea 125 Cladonia gracilis 126 Psoroma hypnorum 127 Cetraria nigricascens 128 Cladonia amaurocraea 129 Lecanora anseris 130 Lecidea atromarginata 131 Solorina aaccata 132 Cladonia uncialis 133 Parmelia separata 134 Pertusaria dactylina 135 Umbilicaria proboscidea 136 Arctomin delicatula 137 Lecanora polytropa da pauper a turn 73 137 25 2 25 25 25 25 600 1450 1650 2000 4.1 7.2 6.2 6.2 - 1.1 1.1 1.1 2.1 1.1 2.1 2.1 3.1 5.2 5.2 2,1 3.1 1.1 2.1 1.1 - 2.1 1.1 4.2 - 4.1 2.1 1.1 1.1 2.1 1.1 1.1 -' 1.1 +.+ - 1.1 1.1 1.1 1.1 1.1 2.1 1.1 - 2.1, 1.1 - 5-2 2.1 - +.+ 2.1 2.1 - 1.1 - Dryadetua *alaaxenala dryado - salicetosum retlculatae - glau< 1 3 5 10 7 61 10 136 9 146 133 178 7 1 ) 50 50 50 50 50 50 50 50 450 1100 1500 1500 1600 1600 1775 1900 2125 2390 5.2 4.1 7.2 8-3 3.1 2.1 1.1 5-1 7.2 6.2 6.2 .3 8.3 9 - 3 ' 8 .3 7 .3 •5.1 - 4.1 4.1 3.1 1.1 1.1 3.1 2.1 1.1 1.1 4.1 1.1 1.1 1.1 3.1 1.1 -- 2.1 2.1 1.1 4.2 4 -2 5-2 3-1 1.1 .1 1.1 1.1 1.1 2.1 3 . ' - 1.1 1.1 1.1 1.1 1.1 3.1 1.1 .1 1.1 2.1 1.1 2.1 1.1 1.1 1.1 - 1.1 1.1 1.1 - - - 1.1 - 1.1 - - 1 . 1 1 . 1 2.1 T.+ - 1.1 - 1.1 - 1.1 1.1 .1 - - 1.1 _ + . + . 1.1 1.1 2.1 1.1 . 1 1 . 1 - - 4.2 4-2 - +.+ - 4.2 3.2 - - 3.2 - 3.1 - 2.1 2.1 3-2 3.1 - 1.1 1.1 - +.+ 1.1 - 1.1 2.2 2.2 - 1 . 1 1 . 1 .1 - - - 1.1 :.1 - +.+ +.+ - 1.1 1.1 - 1.1 - - 1.1 3.1 1-1 - 1.1 - - 1.1 3-1 1.1 '- - 1 - 1.1 1.1 4.2 -- 1.1 - 1.1 1.1 - 1.1 - - 1.1 +.+ 1.1 - 1.1 •.+• - 2.1 - 1.1 - - - - 3.1 1.1 6.2 1.1 1.1 1.1 2.1 +.+ 1.1 1.1 1.1 5-2 2.1 2.1 1.1 4.1 3.1 1.1 3-1 1.1 2.1 - 2.1 1.1 1.1 1.1 1.1 1.1 5-2 1.1 2.1 2.1 - 1.1 - 1.1 1.1 + .-< 4-2 1.1 4.2 I TOTAL SPECIES (incl.sporadics) Sporadic species C layer 138 Ledum decuabens 2(2. 139 Calacagrostis purpurascens 7(2. 37 33 64 49 37 50 60 52 65 64 51 55 68 68 140 Draba nivalii 141 Saxifraga oppositifolia 1/.2 Gentiana propinqua 143 Equisetum arvense 144 Sedura rosea H 5 Smelowskia calycina 146 Woodsia alpina 147 Woodsia glabella 148 Cardamine mlcrophylla 149 Aconitura delphinifolium 150 Antennaria pedunculate 151 Carex uilliamsii 7( 7(1. 9(1. 25(1-61(1. 61 (+. 61(+. 61(+. 73(+. 77(+. 77(2. 77(1. 152 Potentilla Truticosa 153 Ertaphorua vaglnatum 154 KoelerLa cairnsslana 155 Luzula. uahlenbergii 156 Stellaria mcnantha 157 Festuca baffinensis 77(1.1) 133(+.*) 136(1.1) 136(1.1) 136(1.1) 146(2.1) D layer (Bryophytes) 158 CaKpylium chrysophyllua 9(+.+) 159 Canpylium stellatum 10(1.1) 160 Ptilidium ciliare 10(3.2) 161 Lophozia excise 25(+.+ ) 162 Lophozia sp. 77(+.+ ) 163 Lescuraeo patens 104(+.+ ) 164 Cephalozleila aubdentata 165 Dicranoweiaaia crlspula 166 Distichium inclinatum 167 Gymnomitrium coralllc-idei 168 Lophozia quadriloba 169 Pogonatum urnigerura 170 Timmia austrica 171 Tortula ruralia 172 Lophozia alpestris (Lichenes) 173 Cetrsria pinastri 174 Cladonia coccifera 175 Parmelia alplcola 104(+.+ ) 104(1.1) 104U.+) 104(1.1) 104(+.+) 104(1.1) 104(+. +) 137(5-2) 146U.+ ) i Xanthoria elegans 7 Caloplaca festiva J Lecanora atrosulphurea ) Umbilicaria cylindrica D Peltigera spuria 1 Parmelia stygia 2 Parmeliopsls ambigua 3 Stereocaulon tomentosui Cladonia fimbriate 5 Cladonia mitis i Peltigera scabrosa 7 Cladonia pyxidata J Pannaria loucostricta ? Peltigera malacea 7(1.1) 25(t..) 25(1.1) 25(1.1) 61(1.1) 73(2.1) 73(t.+) 1 73(1.D 77(t.+) 77(1.1} 77(1.1) 104(<..t) 137(1.1) 146(1.1) 45 arc brought to surface bv f r o s t a c tio] Figure 11. Exposed ridge (1100 f t ) south of Trout Lake, dominated by Dryas o c t o p e t a l a ( l i g h t green) and S a l i x p h l e b o p h y l l a (dark green) P l o t 62. (Photo by Lambert) Dryas o c t o p e t a l a ssp. a l a s k e n s i s i s the most abundant species forming large p r o s t r a t e mats. Scattered between the Dryas mats are other mat formers such as A r c n a r i a a r c t i c a , Oxytropis nlgrescens, S a x i f r a g a t r i c u s p i d a t a , S a l i x phlebophyJla and Arctostaphylos a l p i n a . The most common non-mat forming species are Lupinus a r c t i c u s , Hierochloe a l p i n a , Antennaria neoalaskana, A r t e m i s i a a r c t i c a and Luzula confusa. No species are r e s t r i c t e d to the de-pauperatum and there are only f i v e constants i n the f o u r p l o t s representing t h i s s u b a s s o c i a t i o n . The presence and moderately high covei'age values of S a l i x p h l e b o p h y l l a i n d i c a t e the c l o s e r e l a t i o n s h i p between the depauperatum and the Salicetum phlebophyllae. I t s subordinate p o s i t i o n i n t h i s subas-s o c i a t i o n can be r e l a t e d to the less exposed p o s i t i o n of the p l o t s which 46 r e s u l t i n g r e a t e r development of mat forming v e g e t a t i o n , e s p e c i a l l y Dryas o c t o p e t a l a . The constant occurrence of Rhytidium rugosum on the d r i e r slopes i s always c l o s e l y a s s o c i a t e d with Dryas o c t o p e t a l a . The bryophyte f l o r a i s s t i l l sparse w i t h only P o l y t r i c h i a , juniperinum, C'eratodon purpureus, and Dicranum elongatum being present i n more than h a l f of the sampled p l o t s . Gymnomitrion c o r a l l i o i d e s , an i n d i c a t o r of exposed h a b i t a t s , i s absent. Due to a r e d u c t i o n i n percentage of exposed rock there are fewer s a x i c o l o u s l i c h e n s present and no constants. F o l i o s e l i c h e n s , e s p e c i a l l y C e t r a r i a c u c u l l a t a , C. n i v a l i s , C. chrysantha and Nephroma expallidum are present, but w i t h low coverage values. Crustose l i c h e n s are conspicuous on both l i v i n g and dead p l a n t m a t e r i a l s and i n c l u d e such species as P e r t u s a r i a panyrga, P_. c o r i c e a , and Lecanora epibryon. A d d i t i o n a l species, are Hypogymnia subobscura, Physcia muscigena and A l e c t o r i a n i t i d u l a . (b) . dryadeto - s a l i c e t o s u m r e t i c u l a t a e - glaucae (Figure 12) In c o n t r a s t to the above s u b a s s o c i a t i o n t h i s community develops on gen t l e to steep, convex to s t r a i g h t more s o u t h e r l y exposed slopes. P l o t s were analyzed that ranged i n e l e v a t i o n from 1500-2390 f t at Canoe Lake and 450-1100 f t at Trout Lake. T h e i r presence at higher e l e v a t i o n s i s r e l a t e d to the more so u t h e r l y exposure. While snow d u r a t i o n i s as long (8 months) as on the depauperatum, snow accumulation i s g e n e r a l l y g r e a t e r because of t h e - l e s s exposed p o s i t i o n . Increased snow accumulation gives more p r o t e c t i o n and reduces surface erosion by wind during the w i n t e r . Drainage i n the s p r i n g i s r a p i d , but because of the g r e a t e r snow cover the h a b i t a t s are g e n e r a l l y moist f o r a longer p e r i o d . By mid-summer, however, the s i t e s are s u b - x e r i c . The amount of exposed rock i s l e s s and i n many p l o t s completely absent. Where present, they are estimated to cover between 2-25 percent of the t o t a l surface area. 47 Figure 12. West f a c i n g slope (2350 f t ) southwest of Canoe Lake, dominated by Dryas o c t o p e t a l a and Lupinus a r c t i c u s ( s c a t t e r e d clumps). (Photo by Krajina)" S o i l p r o f i l e s i n d i c a t e considerably more genetic development than any other u n i t i n t h i s low a r c t i c subalpine zone. However, due to the d i f f e r e n c e i n e l e v a t i o n some p r o f i l e s are b e t t e r developed than others. Frost heaving i s common i n the l a t e s p r i n g and e a r l y summer and the v e g e t a t i v e mats tend to show some downslope movement, although features such as non-sorted s t r i p e s are not recognized. On steeper slopes s o l i f l u c t i o n i s evident from the elongated step-l i k e form of the v e g e t a t i v e mats that l i e p a r a l l e l to the d i r e c t i o n of the slope. F l o r i s t i c a l l y , the dryadeto - salicetosum r e t i c u l a t a e - glaucae i s the r i c h e s t u n i t i n the subalpine zone. This can be r e l a t e d to the more calcareous nature of the s o i l s . S o i l r e a c t i o n i s g e n e r a l l y circum-neutral- to s l i g h t l y a l k a l i n e . D i f f e r e n t i a l species that emphasize t h i s f a c t i n c l u d e S a l i x AS r e t i c u l a t a , S. glauca, Rhododendron lapponicum, Papaver macounii, S i l e n e a c a u l i s , S a x i f r a g a b r o n c h i a l i s , S. h i e r a c i f o l i a , S. h i r c u l u s , S. f l a g e l l a r i s , Cerastium beeringianum, T o f i e l d i a coccinea, Campanula u n i f l o r a , A stragalus  a u s t r a l i s , A. umbellatus, Senecio_ r e s e d i f o l i u s and Parrya n u d i c a u l i s . Constant species a s s o c i a t e d with Dryas o c t o p e t a l a are: Lupinus a r c t i c u s , A r e n a r i a a r c t i c a , Oxytropis nigrescens, Polygonum viviparum and Hierochloe a l p i n a . Bryophytes are more important here than i n the depauperatum. The more moist c o n d i t i o n s of the h a b i t a t s are r e f l e c t e d i n the presence of such species as Aulacomnium t u r g i d urn: Dicranum f uscescens and Hylocomium splendens. Rhytidium rugosum, A b i e t i n e l l a a b i e t i n a and D i s t i c h i u m capillaceum are common ass o c i a t e s w i t h Dryas o c t o p e t a l a and s i m i l a r l y s t r e s s the more calcareous nature of the s u b s t r a t e . These three species have t h e i r optimum development i n t h i s s u b a s s o c i a t i o n . Only one l i c h e n c a l c i p h i l e was present - C e t r a r i a t i l e s i i . The l i c h e n f l o r a i s again more abundant than the b r y o p h y t i c , although coverage values are g e n e r a l l y lower. F o l i o s e species are common among the mat formers and i n c l u d e C e t r a r i a n i v a l i s , C. chrysantha, Hypogymnia subobscura, Nephroma expallidum and P e l t i g e r a canina. C e t r a r i a c u c u l l a t a , C o m i c u l a r i a  divergens and Thamnolia v e r m i c u l a r i s are the major f r u t i c o s e species among the mat v e g e t a t i o n . Crustose species present on dead p l a n t matter i n c l u d e P e r t u s a r i a panyrga, _P. c o r i a c e a , O c h r o l e c h i a u p s a l i e n s i s and Lecanora epibryon. Many species w i t h wide amplitudes of tol e r a n c e are of importance i n the Lupino - Dryadetum * a l a s k e n s i s ; they i n c l u d e Vaccinium uliginosum, B e t u l a glandulose, Arctostaphylos a l p i n a and Poa a r c t i c a . On the more exposed a c i d s o i l s , species composition i s sparse while on the more calcareous s o i l s i t i s r i c h e r . Dryas o c t o p e t a l a and other a s s o c i a t e d species that have t h e i r optimum i n t h i s a s s o c i a t i o n e x h i b i t remarkable adaptation against d e s i c c a t i n g winds. This i s c l e a r l y seen i n the zonation of the veget a t i o n . C l i m a t i c c o n d i t i o n s , 4 9 while harsh, are ameliorated by the more so u t h e r l y exposure of the h a b i t a t s and the deeper snow cover. S o i l development i s g e n e t i c a l l y w e l l advanced i n t h i s a s s o c i a t i o n . Two p l o t s were analyzed i n the Trout Lake area that are c l o s e l y a l l i e d to the depauperatum, however, t h e i r t o t a l species composition would suggest a pos-s i b l e t r a n s i t i o n type community. Several species were recorded only i n these two p l o t s and are not found f u r t h e r to the east at Canoe Lake. They are E r i t r i c h i u m splendens, Cardamine m i c r o p h y l l a , A s t e r pygmaeus and P o t e n t i l l a nivea. Both p l o t s are present on exposed black s h a l e , a substrate not outcropping at Canoe Lake i n the Richardson Mountains. Exposure i s southerly on moderate slopes (15-23°) at e l e v a t i o n s between 485-675 f t . Because they would appear, to be under represented, they have not been included i n the averages f o r the Lupino Dryadetum * a l a s k e n s i s , but have i n s t e a d been added only to show t h e i r p o s s i b l e r e l a t i o n s h i p to t h i s a s s o c i a t i o n . An a d d i t i o n a l p l o t dominated by Carex lug ens at 2025 f t at. Canoe Lake had a high c o r r e l a t i o n c o e f f i c i e n t w i t h the dryadeto - salicetosum r e t i c u l a t a e glaucae. This p l o t has s i m i l a r l y not been included i n the averages as i t i s f e l t t hat f u r t h e r s t u d i e s i n t h i s subalpine zone would show that i t belongs to a separate a s s o c i a t i o n - Caricetum l u g e n t i s . 3. Betulo - Ledetum decumbentis Table 4 (a) $ (b) This a s s o c i a t i o n i s c h a r a c t e r i s t i c of the more n o r t h e r l y exposed slopes between 1300-1900 f t . The slopes are well drained and are g e n e r a l l y q u i t e dry (subxeric) by mid-summer. Exposed felsenmeer i s present i n the m a j o r i t y of the p l o t s s t u d i e d . S o i l p r o f i l e s are predominantly shallow, however, the a c t i v e l a y e r i s s t i l l t h i c k because of the high percentage of rocks present i n the C h o r i z o n . The Betulo - Ledetum decumbentis community i s dominated by many low shrub species that because of t h e i r more exposed p o s i t i o n r a r e l y a t t a i n e d shrub height (over s i x i n c h e s ) . " . 4 b betulo - lodetosum decumbent!a Betulo - Ledetum decumbentis casslopestosum tetragonaa Date Analyzed PLOT DATA Locality Elevation (ft) 18/7 1965 18/6 20/6 20/6 1965 1965 1965 21/8 15/6 1965 1965 11/6 16/6 U/6 1965 1965 1965 630 1310 1350 1350 1450 1475 1725 1850 1900 U/7 13/7 18/6 23/6 23/6 U/6 1965 1965 1965 1965 1965 1965 U/8 10/7 27/7 21/6 27/7 1965 1966 1966 1965 1966 10/6 16/6 10/6 1965 1965 1965 12/8 1966 570 1100 1320 1350 U00 U25 1480 1700 1725 1725 1750,, .1800 1850 1850 Relief: Profile Exposure (°) Slope gradient ( Raised . - Exposed, polygon slope Flat ...Convex, Total 270 0 30 90 Cnv 90 ....Exposed slope. Stg .Straight.. 90 315 0 26 14 10 Dapre- Exposed slope Cnv Stg-Hura Cnv Cvx Cnv Stg Cnv-Hum Cnv 120 45 25 Stone ..Exposed., stripe slope Cnv Stg Cnv 270 45 270 37 3 9 Ridge lee side Cnv 90 10 . ,8^ months.. . - Si- months.. STRATA COVERAGE {%) B ? layer C layer D layer Hops Lichen Dr PLOT COVERAGE (%) by rook SOIL Drainage Hygrotope Depth of s o i l profile (cm) CHEMICAL ANALYSIS No.of samples 60 20 15 25 2 100 85 45 100 95 70 70 60 75 85 70 75 95 70 40 75 95 90 80 90 85 80 55 70 65 15 10 10 5 15 15 25 10 60 30 55 20 50 30 25 25 90 40 55 20 20 10 20 10 50 70 40 40 20 35 20 65 25 30 15 30 20 50 75 40 25 15 45 20 50 55 8 55 3 8 10 15 5 10 5 8 7 20 10 2 25 0M 69 .6 »* 1.65 C/N 24.2 P ppa 12 78.5 1.19 38.3 51.8 .98 30.7 30.4 43 1 59.3 .56 61.4 13 1.05 45.0 54.5 1.26 25.1 51.0 .76 38.9 66.5 1.26 30.6 25 35 2 2 74.1 74 .9 1.2 1.57 35.7 27.6 34 31 No.of samples Organic -Mnieral layei C/N P ppm 17.1 .41 24-2 17.9 • 56 18.5 16.0 .88 10.5 • 74 .52 .8 .46 • 57 • 74 .79 • 24 • 5 .35 .18 .36 .28 .69 • 9 3.6 2.3 2.6 9.2 1.2 17.6 .3 • 9 .6 1.3 2.4 .3 1.6 43.7 26.4 49.0 41.1 54.2 61.0 81.3 3.7 4.1 3.9 4-9 4-4 3.8 3.5 Mineral layer 49-0 1.05 27.0 Ha .57 .82 • 75 • 79 • 53 .8 .5 .61 .74 .79 1.06 .8 .72 .88 .74 K .47 1.04 .75 • 38 1.11 .67 .78 1.25 1.18 .8 • 93 • 73 .9 .82 .98 Ca 11 .7 7 .2 5.8 2 . 2 9 . 8 3 .3 8.7 20 -3 7 .9 3 . 0 12 .9 5.3 7 . 9 30.2 18.0 Mg 3.5 3 .2 2 . 0 • 4 1.3 .9 4 . 8 8 . 0 2 .3 1.2 2.8 1.3 1.0 3 .3 4.1 CEC 104.8 139.0 93 .8 64 .3 47 .6 48.3 36.3 94 .7 168.0 87.9 147.0 67.9 67.3 1 34 .9 91.1 pH 4 . 3 4 . 0 4.1 3 .7 3 . 8 4 . 3 4 . 4 4 . 4 4 -2 3 -8 4 . 2 4 - 2 3 .8 3.5 4 - 9 0M 4-1 9.4 2 .3 3 .3 1.1 2 .0 3.3 2.1 9 . 9 4 . 6 1.1 2 .0 1.6 2.9 4 . 9 KI -15 .22 .23 .09 .04 .07 .08 • » .28 .15 .06 .09 .14 .11 .25 C/N 15.9 19.7 5.8 19 .5 16.0 16.6 23.9 12 .8 20.5 17.8 10.6 12 .9 6 . 6 15-2 8 11.3 P PPB 21 12 14 4 16 4 3 5 6 13 14 8 7 6 Ha .73 • 73 • 59 .82 .77 -5 .8 • 51 .41 .72 .81 • 79 .72 .89 .62 K .24 .17 .19 .5 .08 .08 .12 .13 .17 .21 .1 .09 .19 .31 .31 Ca 1.1 1.1 1.8 • 9 .8 1.3 1.2 2 .2 8.1 2 .7 .9 1.2 2 .5 14.4 7.9 Mg .4 .25 .46 .05 . 0 .0 .1 1.4 2 .3 .8 .0 .2 .1 .4 1.2 CEC 32.3 4 6 . 3 18.0 27.6 19.5 1B.3 4 8 . 3 15 -2 43.6 36.9 39.1 19.9 17.5 43 .0 13 .0 PH 4-1 4 . 4 4.1 4 . 3 4 . 7 4 . 6 5.1 5 .0 5 .5 4 . 3 4 . 4 4 . 5 4.1 4 .0 6 . 3 1 4-4 .15 17.0. 3 .78 • U 2.2 25 14 12 12 30 2 1 1 1 82.6 56.3 36 .9 82.6 1.73 1.05 1.12 1.73 27.6 31.1 19.1 27.7 22 27 17 34 .89 .8 • 64 1.06 1.08 1.19 • 85 .85 29.2 7 .8 9 . 0 19.3 4.1 3 .4 2 - 3 4 . 6 86.1 148.0 67.8 126.2 4 . 9 4 . 5 3.8 4 . 2 27.9 28.2 21 .5 • 55 .98 .43 29.4 16.8 29.0 16 19 24 .89 • 56 • 79 .63 .69 .45 21.0 5 -4 2 .6 4.1 1.1 .7 58.4 43 .6 67.3 5 -3 3 -6 4.1 1 1 1 2 5 -5 6 .3 1.7 2 .4 • 15 .17 .07 .09 21-3 21 .5 14.1 10.9 18 10 6 12 .89 .8 .74 • 73 .26 • 33 .09 .28 8.9 1.7 .8 5-8 .9 .8 .0 .8 22.3 28.1 13.7 25.9 5-1 4 .6 4 .7 4.4 4 a Number of Plots Elevation (ft) 1 Betula glandulosa 2 Salix pulchra 3 Salix glauca 4 Spiraea beauverdiana Betulo - Ledetum decumbentis betulo - ledetosun decumbentis ca3slopeetosum tetragonae 1 2 3 4 5 6 7 8 9 89 24 31 30 121 16 6 20 14 100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 70 67 23 36 35 12 114 131 166 33 163 3 19 5 179 630 1310 1350 1350 1450 1475 1725 1850 1900 570 1100 1320 1350 1400 1425 1480 1700 1725 1725 1750 1800 1850 I85O 1900 Constancy Cover Betula glandulosa Salix pulchra Salix glauca Spiraea beauverdiana 5 Ledum decumbens 6 Vaccinium vitis-idaea 7 Arctostaphylos alpina 8 Vaccinium uliginosum 9 Hierochloe alpina 10 Cassiope tetragona 11 Empetrum hermaphroditum 12 Carex podocarpa 13 Polygonum biatorta 14 Salix phlebophylla 15 Loiaeleuria procumbens 16 Luzula confuse 17 Poa arctica 18 Arctagroatis l a t i f o l i a 19 Carex lugena 20 Diapensia lapponica 21 Saussurea angustifolia 22 Arenaria arctica 23 Oxytropis nigrescens 24 Pedicular!3 labradorlca 25 Polygonum viviparum 26 Douglasla arctica 27 Pedicularia lanata 28 Anemone narcissiflora 29 Petasites frigidua 30 Dryas oc to petals 31 Artemisia arctica 32 Lupinus arcticus 33 Saxifraga bronchialio 34 Saxifraga punctata 35 Arnica lessingii 36 Tofieldia coccinea 37 Selaglnella aibirica. 38 Pedicularia capitate 39 Equisetum arvense 40 Pyrola grandiflora 41 Pedlcularis arctica 42 Pedicularia lapponica 43 Senecio atropurpureus 44 Poa glauca 45 Antennaria neoal a alcana 46 Polygonum elaskanura 7.3 4.2 1.1 6.2 4.1 3.1 6.2 6.2 4.2 3.1 7.2 5.1 6.2 4. 2.1 1.1 3.1 6.2 3.1 6. 5.2 1.1 1.1 1.1 5-2 3.1 1.1 2.1 1.1 2.1 2.1 2.1 . 6.2 2.V. 2. 1.1 2.1 1.1 2 4-2 4.2 1 2.1 +.+ 2 - 2.1 •• 2.1 1.1 6.2 2.1 1.1 6.2 5-2 5.2 4.2 5.2 1.1 6.2 2.1 - 2.1 1.1 1.1 - - 2.1 -4.1 1.1 3.2 6.2 1.1 3.1 5.2 6.2 4-1 3.1 3.1 1.1 4.2 2.1 2.1 6.2 2.1 2.1 2.1 4.2 4.1 4.1 4.2 1.1 4.2 2.1 5.2 2.1 3.1 5.2 4.2 5-2 4.2 2.1 3.1 2.1 4 -2 5.2 4.2 5.2 6.2 4.1 6.2 1.1 1.1 .1.1 .2.1 2.1 1.1 2.1 2.1 1.1 2.1 2.1 3.1 2.1 2.1 5-2 5-2 5-2 7.3 3.2 2.2 6.3 8.3 6.2 7.2 4.2 - 3.2 5.2 3-1 - 2.1 5-2 4.2 4.2 4.1 2.1 1.1 2.1 1.1 2.1 1.1 1.1 2.1 .3 7.3 4.2 4.2 1.1 3.1 2.1 1.1 - 3.2 4-2 4.1 2.1 3.1 - 1.1 1.1 47 Dicranum elongatum 48 Po ytrichum juniperlnum 49 Aulacomnium turgidum 50 Sphenolobua minutus 51 Hylocomium splendens 52 Dicranum fuscescens 53 Ptilidium ciliare 54 Rhytidium rugosura 55 Rhacomitrium lanuginosum 56 Sphagnum girgensohnii 57 Dicranum scoparium 58 Dicranum groenlandicum 59 Aulacomnium paluatre 60 Dicranum an gust urn 61 Polytrichum piliferum 62 Oynnomitrion corallioides 63 Sphagnum lenenae * 64 Sphagnum rubellura 65 Ceratodon purpureus 66 DrepanOcladus uncinatus 67 Hypnum callichroum 68 Calypogeia trichomanis 69 Lophozia vontricoaa 70 Pohlia sp. 71 Eurhynchium pulchelluin 72 Lophozia ap. 73 lophozia alpestrls 74 Pohlia nutans 75 Chandonanthus setiformls_ 76 Tetraplodon paradoxus 77 Lophozia obtusa (Lichenes) 78 Cetraria cucullata 79 Cladonia mitis 80 Cetraria lslandica 81 Cetraria nivalis 82 Cladonia rangiferlna 83 Cetraria richardsonli 84 Thamnolla vermicularis 85 Dactylina arctica 86 Stereocaulon alpinum 87 Cornicularia divergens 88 Alectoria ochroleuca 89 Sphaerophorus globoauo 90 Ochrolochia frigide 91 Rhizocarpon geographicum 92 Cladonia gracilia 93 Cetraria nigricascens 94 Peltigera aphthosa 95 Alectoria nigricans 96 Umbilicaria hyperborea 97 Nephroma expallidum 98 Parmelia stygia 99 Peltigera scabrosa 100 Umbilicaria proboscidea 101 Parmelia omphalodea 102 Pertusaria dactylina 103 Alectoria miniscula 104 Cladonia uncialis 105 Parmelia separata 106 Pertusaria panyrga * 107 Cetraria chrysantha 108 Lobaria l i n i t a 1C9 Pertusaria coriacea 110 Haematomma lapponicum 111 Peltigera spuria 112 Peltigera canina 113 Stereocaulon tomentosum 114 Paoroma hypnorum 115 Cetraria hepatison 116 Cladonia chlorophaea 117 Lacidaa lapicida 118 Cetraria kaniezatica 119 Lecanora epibryon 120 Solorina crocea 121 Lecidea atromarginata 122 Peltigera oalacea 123 Cladonia amaurocraea 3.1 4.2 2.1 3.1 6.2 1.1 1.1 1.1 4.2 1.1 3.1 2.1 1.1 1.1 5.2 1.1 1.1 2.1 3.1 - 3.1 5.2 5.2 1.1 1.1 8.3 5-2 7.2 1.1 3.1 1.1 6.2 4.1 4.2 2.2 4-2 2.2 1. ' 1.1 2.1 1.1 1. 1.1 3-1 1 2.1 1.1 • 3.1 +.+ 2.1 1.1 2.1 4.1 +.+ 2.1 2.1 1.1 4.2 - 1.1 5.2 1.1 2.1 - 1.1 - 1.1 1.' 1.1 1.1 1.1 +.i - 1.1 1.1 1.1 4-1 1.1 1.'l IJU Lecanora aLrosmpnurea - 1.1 - - - - - - - - - - - - - - - - - L 131 Lecidea f lavocaerule scena - - - - - - - - - - - - - 1,1 - - - - - - - - - 1 TOTAL SPECIES (lncl.sporadics) 26 41 46 26 23 30 60 42 31 55 52 41 41 44 48 73 23 64 67 49 50 24 45 42 Sporadic opocies C layer 3 layer (Bryophytas) 132 Lycopodium selago 3(1.1) 148 Cynodontiun polycarpon 3d 1) 164 Braehytheciun sp. 166(1 1) 178 Cladonia pleurota 33( + .+) 133 Saxifraga tricuspidata 6(1.1) 149 Dicranum nflhlenbockil 3(1 1) 165 Cephalozia bicuspldata 166(+ 179 Lacanort ruplcola 33(+.+ ) 134 Salix rlchardaonii 12(1.1) 150 Lophozia badensls 3(t -0 166 Lophozia tun ana 166(+ + ) 180 Ochrolochla inaaquatula 33(+.+) 135 Calamngrostia lapponica 24(+.+ ) 151 Encalypta vulgaris 6(2 1) 167 Lophozia quinquedentata 166(+ +) 181 Parmelia alplcola 33(1.1) 136 Linnaea borealis 33(2.1) 152 Hypnua plicatulira 12(1 1) 168 Philonotia fontana 166(1 1) 182 Parmelia physoda9 33<+.+) 137 Geum glaciale 67(1.1) 153 Hardla compress* 16<+ +) 169 Scnpe.nl a irrigua 166(+ 183 Cladonia verticlllata 70(».+ ) 138 Luzula wahlanbergii 70( +. + ) 154 Maraupella varianB 24(1 1) 170 Sphagnum tares 166(+ + ) 184 Hypogymnia aubobscura 70(1.1) 139 Salix brachycarpa 70(1.1) 155 Oncophorua schiatii 24 (+ +) 185 Cetraria acholanderi 114(1.1) 140 Smelovakl calycina 70(1.1) 156 Rypnum hamulosum 33 ( + +) (Lichenes) 186 Cladonia coniocraea H4<+.+ ) 141 lycopodium annotinum 13K2.1) 157 Mnium rugicum 33 (+ +) 171 Cetraria nigricans 3(1 1) 187 Cetraria laevigata 121(2.1) 142 Senecio yukonenais 131(1.1) 158 Ptilium crista-castrensis 33(1 1) 172 Parmelia alraquistii 14(+ + ) 143 Senecio fuscatus 163(1.1) 159 Bryum sp. 70(2 1) 173 Parmelia fraudans 24(1 1) 144 Stellaria longipes 163(1.1) 160 Cephalosiella subdentata 70( + •0 174 Pertusaria subobducens 24(+ 1-) 145 Anemone parviflora 166(1.1) 161 Tooenthypnum nitons 89(1 1) 175 Cladonia gonecha 30( + +) 146 Salix chamissonis 166(5.2) 162 Pleuroaium achreberi 163(1 1) 176 Cladonia fareata 30(+ 147 Stellaria cillatoaepala 166(2.1) 163 Blepharostona trlchophyllua166(+ + ) 177 Locanara polytropa 30<+ 50 Two s u b a s s o c i a t i o n s are described, the b e t u l o - ledetosum decumbentis and the cassicpeetosum tetragonae, which i s s l i g h t l y chionophilous. (a) b e t u l o - ledetosum decumbentis [Figure 13) The c h a r a c t e r i s t i c combination of species of t h i s s u b a s s o c i a t i o n are present on more n o r t h e a s t e r l y and northwesterly exposed slopes at e l e v a t i o n s between 1300-1900 f t . They vary i n p r o f i l e from s t r a i g h t to convex to concave and are u s u a l l y on g e n t l y to moderately steep slopes (4-30°). Snow does not p e r s i s t i n the b e t u l o - ledetosuni decumbentis a f t e r l a t e May or e a r l y June. There i s probably l i t t l e d i f f e r e n c e i n d u r a t i o n of snow cover (approximately 8 1/2 months) between t h i s s u b a s s o c i a t i o n and the Lupino - Dryadetum * a l a s k e n s i s . I n d i c a t i o n s are that snow accumulation i s g r e a t e r i n these s i t e s thereby g i v i n g increased p r o t e c t i o n from abrasive winter winds as no wind eroded areas were observed. However, because of t h e i r p o s i t i o n on the (mid to upper) slope there i s l e s s p r o t e c t i o n from the p r e v a i l i n g northwest winds once the snow has disappeared i n the s p r i n g and before i t i s again covered i n the autumn. The u n d u l a t i n g topography g e n e r a l l y a s s o c i a t e d w i t h the sampled p l o t s would appear to c l o s e l y resemble the s o i l t e r r a c e s i n Alaska described by Sigafoos and Hopkins (1952). Downslope movement caused by creep would seem t o be very slow and i s r e f l e c t e d i n the lack of height i n the mounds. Drainage on these slopes i s ra.pid each s p r i n g w i t h moisture c o n d i t i o n s more mesic to sub-xeric throughout the summer. Exposed rocks are present i n h a l f of the sampled p l o t s and are a l s o abundant j u s t below the v e g e t a t i v e mat. However, there appears to be no non-sorted s t r i p e or polygon arrangement to them. The r e l a t i v e l y t h i c k v e g e t a t i v e mat probably i n h i b i t s f r o s t heaving and plays a major r o l e i n re-t a r d i n g downslope movement of rock and rubble. S o i l p r o f i l e s are shallow i n a l l communities, between 19-33 cm i n depth, and o v e r l i e coarse i c e shattered parent m a t e r i a l . The p r o f i l e s i n d i c a t e g r e a t e r s t a b i l i t y r e l a t i v e to f r o s t 52 displacement by t h e i r c o n t i n u i t y of p r o f i l e morphologies. S o i l r e a c t i o n ]s moderately to s t r o n g l y a c i d . Figure 13. Betulo - Ledetum decumbentis b e t u l o - ledetosum decumbentis at 1700 f t , Canoe Lake. Exposed rocks give e v i -dence of f r o s t heaving, mounds i n d i c a t e downslope movement. (Photo by K r a j i n a ) Constant v a s c u l a r species a s s o c i a t e d w i t h Betula glandulosa and Ledum decumbens but with reduced coverage values are: Vaccinium v i t i s - i d a e a , A rctostaphylos a l p i n a , Hierochloe a l p i n a and Vaccinium uliginosum. One or more of the a s s o c i a t e d woody species may be abundant i n some p l o t s than e i t h e r Betula glandulosa or Ledum decumbens, but the l a t t e r are always prominent i n the su b a s s o c i a t i o n . A d d i t i o n a l major species i n c l u d e Care_x podocarpa and Luzuia  confusa. Where drainage might be impeded and more moist c o n d i t i o n s p r e v a i l during the summer t h i c k mats c f Emuetrum hermaphroditurn are o c c a s i o n a l l y present. The few shrubs that are present are l e s s than twelve inches i n height 52 and u s u a l l y r e c e i v e some p r o t e c t i o n from the mounds. The constant occurrence o f Dicranum elorigatum i n d i c a t e s the w e l l drained c o n d i t i o n of the p l o t s . Present i n the Lh elongatum cushions i s Sphenolobus  minutus. An a d d i t i o n a l i n d i c a t i o n of the su b - x e r i c c o n d i t i o n s i s the presence of Polytrichum juniperinum. In more moist m i c r o h a b i t a t s are Aulacomnium turgidum and Dicranum fuscescens. Lichens are numerous on the d r i e r areas of the mounds and provide more surface coverage than the species present on the more mesic s i d e s . Species present on the d r i e r p a r t s i n c l u d e C e t r a r i a c u c u l l a t a , C_. n i v a l i s , Thamnolia v e r m i c u l a r i s , A l e c t o r i a ochroleuca, A. n i g r i c a n s and C o r n i c u l a r i a divergens . Cladonia m i t i s , C_. r a n g i f e r i n a , £^jtraria isla n d i c a. , C_. r i c h a r d s o n i i D a c t y l i n a a r c t i c a and Stereocaulon alpinum are present on the more mesic sides of the mounds. Numerous crustose species are present on dead p l a n t m a t e r i a l and i n c l u d e such species as Ochrolechia f r i g i d a , P e r t u s a r i a d a c t y l i n a , F\ panyrga and P. c o r i a c e a . (b) cassiopeetosum tetragonae (Figure 14) Ha b i t a t s dominated by Cassiope tetragona occur on predominantly north f a c i n g slopes where moderately l a t e m e l t i n g snow provides downslope seepage during the e a r l y summer. While' t h i s community might be considered as s l i g h t l y chionophilous the i n a b i l i t y of Bet u l a glandulosa to t o l e r a t e prolonged periods of snow cover suggest that i t s d u r a t i o n i s never so l o n g - l a s t i n g as i n the true chionophilous communities. A l l sampled p l o t s are a s s o c i a t e d with e i t h e r slope depressions, c r e v i c e s or non-sorted s t r i p e s between 1320-1900 f t . Slope g r a d i -ents range from 2-47°. Exposed rocks are present i n every p l o t but one, and are estimated to cover between 2-35 percent of the surface area. P l o t s as-s o c i a t e d w i t h non-sorted s t r i p e s are at higher e l e v a t i o n s and on more exposed slopes. Snow cover i n these s i t e s i s l e s s than on those at lower e l e v a t i o n s . Snow accumulation, however minimal, i s s u f f i c i e n t to p r o t e c t the un d e r l y i n g v e g e t a t i o n from d e s i c c a t i n g winds and sudden changes i n temperature during the e a r l y part of the annual thaw. Duration of snow i s estimated to be 8 1/2 months. Figure 14. Betulo - Ledetum decumbentis cassiopeetosura tetragonae on east f a c i n g slope (1400 f t ) , Canoe Lake. Scat t e r e d mats of Dryas o c t o p e t a l a are present on r a i s e d m i crohabitats a l s o present i n d i v i d u a l stems of Lupinus a r c t i c u s . (Photo by Lambert) S o i l p r o f i l e s are shallow w i t h parent m a t e r i a l s present d i r e c t l y beneath the v e g e t a t i v e mat i n many areas. Drainage i s r a p i d at higher e l e v a t i o n s so that surface m a t e r i a l s show l i t t l e evidence of disturbance due to f r o s t a c t i o n Cassiope tetragona dominated p l o t s i n the depressions at lower e l e v a t i o n s are consi d e r a b l y l a r g e r i n o v e r a l l area than those a s s o c i a t e d w i t h the non-sorted s t r i p e s . Sncw d u r a t i o n i s probably two to three weeks longer i n these lower s i t e s (9 months). M i c r o r e l i e f i n the depressions i s mainly low hummock or t e r r a c e form. Downslope movement i s more evident and can probably be r e l a t e d to the g r e a t e r accumulation of snow. Drainage i s l e s s r a p i d and the a c t i v e l a y e r remains moist w e l l i n t o the summer. S o i l s are shallow with many large rocks both exposed and j u s t below the surface. Buried organic matter found under mineral s o i l i s evidence of the dis t u r b e d nature of the s u b s t r a t e . R e l a t i v e l y large pure patches of Cassiope tetragona are never present, although Cassiope d i d have the highest average cover value f o r t h i s subassocia-t i o n . Constant species i n c l u d e Betula glandulosa, Ledum decumbens, Vaccinium v i t i s - i d a e a V. uliginosum, Arctostaphylos a l p i n a and Hierochloe a l p i n a . Ad-d i t i o n a l species present w i t h lower constancy values are Empetrum hermaphroditum, Carex podocarpa, Polygonum b i s t o r t a , S a l i x p h l e b o p h y l l a , L o i s e l e u r i a procumbens, Poa a r c t i c a and Luzula confusa. D i f f e r e n t i a l species that emphasize the more moist c o n d i t i o n of the subassociation. are P e t a s i t e s f r i g i d u s and S a x i f r a g a punctata. Several species a t t a i n e d shrub height such as Betula glandulosa, S a l i x p u l c h r a , S_. s l a u c a and Spiraea beauverdiana. These sp e c i e s , however, are more abundant i n the C l a y e r as low p r o s t r a t e forms. Species present on the hummock tops are i n d i c a t i v e of the more sub-xer i c c o n d i t i o n i n c l u d e S a l i x p h l e b o p h y l l a , Carex podocarpa, A r e n a r i a a r c t i c a , Lupinus a r c t i c u s , Carex lugens and L o i s e l e u r i a procumbens. Large mats of Arc t ostaphy1os a l p i n a are present on low hummocks which are moist i n e a r l y summer and dry out ap p r e c i a b l y l a t e r i n the summer. In micr o h a b i t a t s that remain more moist, Empetrum hermaphroditum forms l a r g e mats. Dicranum elongatum, Aulacomnium turgidum, Polytrichum juniperinum and Sphenolobus minutus are constant bryophytes. The occurrence o f Hylocomium splendens, Sphagnum g i r g e n s o h n i i , S. lenense and Polytrichum p i l i f e r u m d i f - . f e r e n t i a t e t h i s l a y e r from the b e t u l o - ledetosum decumbentis. Polytrichum p i l i f e r u m i s . i n d i c a t i v e o f surface disturbance when present. Lichen species that d i f f e r e n t i a t e t h i s l a t e r from the previous s u b a s s o c i a t i o n are P e l t i g e r a  scabrosa, _P. malacea, S o i o r i n a crocea, D a c t y l i n a madreporiformis, Nephroma expallidum and Cladonia c o c c i f e r a . Although these species are of low constancy, they do emphasize the prolonged snow cover and increased moisture. Two p l o t s (31 and 179) dominated by L o i s e l e u r i a procumbens 'and having a high c o e f f i c i e n t of s i m i l a r i t y with the Betulo - Ledetum decumbentis are 55 included w i t h t h i s a s s o c i a t i o n and not placed i n t o a separate a s s o c i a t i o n ( h o i s e l e u r i e t u m ) . This i s s u b s t a n t i a t e d by the f a c t that p l o t 31 has a high-er c o r r e l a t i o n w i t h the b e t u l o - ledetosum decumbentis while p l o t 179 i s more c l o s e l y a l i g n e d to the cassiopeetosum tetragonae. Rates of drainage and snow du r a t i o n would appear to d i s a s s o c i a t e these two s u b a s s o e i a t i o n s . However, a l l the p l o t s have high c o e f f i c i e n t s of s i m i -l a r i t y . Moisture c o n d i t i o n s are g e n e r a l l y considered to be more sub-mesic than mesic. The cassiopeetosum tetragonae although s t i l l moist i n mid-summer has u s u a l l y d r i e d out c o n s i d e r a b l y by the end of the summer. Many species i n t h i s subalpine zone have broad amplitudes of t o l e r a n c e and a l l i n d i c a t i o n s are that these two s u b a s s o e i a t i o n s , dominated by Betula glandulosa and Ledum decumbens, comprise the maj.or 'heath' type v e g e t a t i o n on the higher elevated more n o r t h e r l y exposed slopes. Deeper snow cover p r o t e c t s the community from d e s i c c a t i o n and s u p p l i e s i t w i t h a d d i t i o n a l moisture during the i n i t i a l stages of v e g e t a t i v e growth each s p r i n g . 4. V a c c i n i o - Betuletum glandulosae Table 5 (a) 5 (b) The V a c c i n i o - Betuletum glandulosae i s considered to represent the c l i -matic 'climax' i n the subalpine zone. Communities of t h i s a s s o c i a t i o n occupy approximately 30 percent of the t o t a l area covered i n t h i s study. Habitats are present on the mid to upper s l o p e s , but are a l s o present on some lower s l o p e s , exposed lake and creek banks. Low shrubs are present i n these l a t t e r two s i t e s and i n s h e l t e r e d depressions on the upper slopes. Analyzed p l o t s v a r i e d i n e l e v a t i o n from 1100-1900 f t at Canoe Lake and from 380-1270 f t at Trout Lake. A l l s i t e s are moderately w e l l drained, although v a r y i n g slope gradients (2-36°) would suggest the r a p i d i t y of drainage v a r i e d between habitats.. Where drainage i s slow the saturated s o i l s are prime s i t e s f o r downslope move-ment. Freeze-thaw c y c l e s are common i n May and e a r l y June during the thaw. The areas d e l i n e a t e d by t h i s type are u s u a l l y a mosaic of s o l i f l u c t i o n r e l i e f . 5 b Vaccinio - Betuletum glandulosae vaccinio - betulosum glandulosae (fruticulo3um) vaccinio - betulosum glandulosae Plot No. Plot size (m2) 74 99 60 66 41 139 55 113 134 135 28 118 78 100 76 100 86 50 161 100 101 100 17 50 26 50 Date Analyzed 15/7 1965 21/7 1965 12/7 1965 13/7 1965 2/7 1965 12/7 1966 6/7 1965 14/8 . 1965 11/7 1966 11/7 1966 19/6 1965 21/8 1965 16/7 1965 15/7 1965 18/7 1965 26/7 1966 9/8 1965 15/6 1965 19/6 1965 PLOT DATA Locality Elevation (ft) TL 550 TL 570 TL 930 TL 1270 CL 1100 CL 1100 CL 1250 CL 1325 CL 1500 CL 1525 CL 1760 CL 1900 TL 380 TL 400 TL 660 DL 1100 CL 1250 CL 1400 CL 1650 PHYSIOGRAPHY Land form Relief: Profile Exposure ( ° ) Slope gradient ( ° ) CLIMATE Snow duration STRATA COVERAGE {%) B2 layer C layer D layer Moss Lichen Dr PLOT COVERAGE (%) by rock SOIL Drainage Hygrotopo Depth of active layer (cm) CHEMICAL ANALYSIS No.of samples Organic layer Depre-ssion Lake •Exposed slope. ...Exposed slope.. Drain-Old slide age way Flat-Hum Flat Cvx-Hum Cvx Cvx Cvx-Hum Cvx-Hum Stg-Hum Cvx-Hum Stg-Hum 45 315 0 0 45 90 90 90 90 90 0 120 0 1 22 15 20 6 11 8 4 3 21 U No.of samples Organic -Mineral layer No.of samples Mineral layer 85 AO 10 1 65 95 85 95 95 90 90 95 90 40 80 50 55 30 60 35 55 60 65 75 40 15 10 30 35 20 35 20 25 25 .Moderate to well-drained. Mesic 0M 47.6 22.1 72.5 77.0 64-5 53.2 56.3 N* .92 .63 1.26 1.4 1.4 .88 • 94 C/N 30.0 20.3 33.4 35.1 33.8 35.1 34.7 P ppm 18 10 29 48 33 32 25 Na .54 • 42 • 44 .97 .72 .8 .73 .8 K .65 .64 1.57 1.45 1.5 1.95 Ca 1 4 . 8 13.8 17.2 21.6 20.0 13.5 17.9 Mg 4-4 3 .8 5.4 8 . 3 6.3 5.0 4.3 CEC 36.1 3 9 . 6 184.0 202.5 107.6 74.0 69.7 pH 4 . 6 5.3 4 . 6 4 . 8 4.7 5-0 4.3 0M 20.7 35.9 8 . 3 Hf • 36 .31 . 5 6 C/N 33.4 67.2 8.6 P ppm 5 8 3 Na . 5 3 • 39 .42 K .38 .21 .13 Ca 7.0 9.7 5.4 Mg 1.3 2.1 1.7 CEC 46.1 43.0 28.4 pH 4.3 5.4 4.8 2 1 . 4 .51 28.0 8 .56 ,55 11.6 3.6 54.1 5.0 1 0M 5-8 3.0 7.6 10.0 3.0 3 .6 .1 N$ .36 .16 .26 • 39 .17 C/N 12.5 1 0 . 9 16.9 14.9 12.8 23.0 P ppm 2 14 5 5 6 5 Na .48 .37 • 43 .38 • 59 • 44 K . 1 3 .1 • 15 . 1 9 • 25 • 3 Ca 3 . 1 5 .1 3 - 8 4 -5 5 - 6 3 .9 Mg . 5 1 . 3 1.0 1 .3 1.6 1.7 CEC 27.9 32.1 33.4 38.2 24-0 27.8 pH 4 - 4 5.1 4.7 4-7 4-7 5.0 1 1 3 . 3 . 5 9 13.1 13 . 5 6 1.63 13.1 4 - 5 26.6 5.1 1 1.2 .18 4 . 4 4 .6 • 41 8 .4 2 .0 10.2 5 . 0 1 .2 .03 1 9 . 5 7 .7 • 4 6.0 3.0 1 9 . 5 4 - 5 8.6 8 • 83 .25 5.8 1.5 25.1 4.5 40 85 90 30 1 11.4 .25 26.4 14 .62 .48 9-4 1.6 29.0 4-5 1.4 .22 4.1 6 .61 .29 6.8 1.7 17.5 4.8 .Old river. Exposed Raised Expcsed Depression bank slope poljgon. slope Stg Stg-Hum Cnv Cvx Stg-Hum Cnv Cnv 135 90 200 Total 135 270 315 36 10 16 2 10 29 5 15 45 25 85 30 60 75 85 60 85 60 70 40 25 55 20 20 80 75 40 65 10 10 10 45 50 15 2 15 3 2 -Moderate to well-drained. Mesic 48.3 52.2 65.5 4 0 . 0 1 .4 1 .4 1 .4 1.12 20.0 21.6 27.1 20.7 3 13 16 38 .81 .73 .71 • 57 • 55 2 .14 .86 .98 23.3 10.5 33.5 17.4 10.0 4 . 7 10.1 5.6 1 4 7 . 0 43.6 174.0 39 .4 5.6 4 . 3 5-2 5 .0 1 87.4 1.63 3 1 . 1 17 .98 . 7 4 23.6 4 . 6 104-5 4 . 3 60.8 65.6 1 .12 1.47 31-5 25-9 54 26 .79 .81 1.86 1.4 10.2 5.2 5.2 2.8 157.0 193.0 4.5 4 .1 18.8 .7 15.6 5 • 58 .17 18.5 5-2 82.3 5-9 8.2 .19 2 5 . 7 7 .44 .3 7.1 1.6 26.1 4.8 17.2 .48 20.7 6 .42 .24 5.8 2.0 28.0 4.6 2.7 .13 11.9 4 .43 .12 5.4 2.1 21.2 5.3 3.6 .18 10.6 6 .72 .44 6.8 2.5 23.3 4.4 6.2 .09 4 0 . 0 8 .74 .25 1.1 .3 67.3 3.9 Table No. 5 a Number of Plots Elevation (ft) Vaccinio - Betula turn glandulosa a vaccinio - betulosun glandulosae (f ruticuloaun.) vaccinio - betulo sum glandulosae (rruticosum) 1 2 3 4 5 6 7 6 9 10 11 12 74 99 60 66 41 139 55 " 3 134 1 35 28 118 550 570 930 1270 1100 1100 I25O 1325 1500 1525 1760 1900 1 2 3 4 5 6 7 78 76 86 161 101 17 25 100 100 50 too 100 50 50 380 400 660 1100 1250 1400 1650 1 Betula glanduloi 2 Salix glauca 3 Salix pulchra Betula glandulosa 4 Vaccinium uliglncoum 5 Carex lugena 6 Ledum dacumbens 7 Vaccinium vitla-ldaea Salix pulchra 8 Arctostaphylos alpina 9 Polygonum blstorta 10 Hierochloe alpina 11 Empetrum hermaphroditum 12 Arctagrostis l a t i f o l i * 13 Salix phlebophylla 14 Poa arctica 15 Anemone narclasiflora 16 Lupinus arcticus 17 Petasitea frlgidus 13 Luzula confusa 19 Stellaria ciliatosepala 20 Dryas oc to petal a 21 Pedicularia lanata 22 Senacio atropurpureus 23 Pedicularis arctica 24 Polygonum vlvlparura 25 Pedicularis labradorlca 26 Tofieldia cocclnaa 27 Saussurea angustlfolla 28 Pedicularia capitata 29 Eriophorum vagina turn 30 Salix brachycarpa 31 Pyrola grandiflora 32 Cassiope tetragona 33 Oxytropis maydelliana 34:Equisetum arvense 35 Senacio fuscatua 36 Antennaria neoalaakana 37 Pedicularia lapponica 38 Saxifraga punctata 39 Artemisia arctica 40 Stellaria longlpas 41 Saxifraga trlcuepidata 42 Kobresia myaauroldaa 43 Cardamina digitate 44 Salix reticulata 45 Pyrola secunda 46 Calamagrostls canadensis 47 Luzula nivalia 48 Arenaria arctica 49 Castilleja raupli D layer (Bryophytes) 50 Aulacomnium turgidum 51 Polytrichum Junlperlnuo 52 Hylocomium splandens 53 Dicranum elongatum 54 Rhytidium rugosua 55 Sphagnuo girgansohnil 56 Aulacomnium paluatre 57 Sphenolobua minutua 58 Dicranum angustum 59 Dicranum groenland1cum 60 Dicranum fuscescena 61 Lophozia sp. 62 Bryum sp. 63 Pleurozlum schreberl 64 Dicranum acoparium 65 Ptilidiura ciliara 66 Dicranum muhlenbecxli 67 Hypnura callichroum 68 Sphagnum rube Hum 69 lophozia quinquedantata 70 Distichium capillaceua 71 Drepanocladus uncinatus 72 Tomenthyjmum nitons 73 Cslypogeia trlchomania 74 Eurhynchlimi pule he Hun 75 lophozia kunzeana 76 Blepharo stoma trlchophyllum 77 lophozia alpestrls 78 Tetraplodon paradorua (Lichenes) 79 Cetraria cucullata 80 Cetraria islandica 81 Peltigera aphthosa 82 Cladonia mitls 83 Thamnolia vermicularia 84 Stereocaulon alpinum 85 Cetraria nivalia 86 Cladonia rangiforlna 87 Cladonia amaurocraea 88 Nephroma expo1ltdurn 89 Dactylina arctica 90 Peltigera oanina 91 Cladonia gracilis 92 Peltigera scabroaa 93 Sphaerophc-rus globosus 94 Cetraria richardoonli 95 Cladonia uncialia 96 Lobaria l l n l t a 97 Alectoria ochroleuca 98 Cornicularia divergens 99 Peltigera polydactyla 100 Psoroma hypnorum 101 Alectoria nigricans 102 Hypogymnia subobacura 103 Peltigera spuria 104 Cetraria chrysantha 105 Ochrolochia frigida 106 Parmelia cmphalodea 107 Alectoria nltldula 108 Stereocaulon tomentoaum 109 Cladonia goneeha 110 Cladonia chlorophaea 5.2 4 .2 4 2 3-1 6.2 6.2 6.2 7.3 5.2 5.2 2.1 7.2 •> ? •> ? •> V 5.5 4 .2 5-2 5 2 6.2 4.1 4 .2 3-1 4.2 4 .2 2.1 1.1 5.2 7.2 6 .3 4 .2 4 .2 6.2 - 2.1 V 4.0 6.2 1.1 5 2 1.1 2.1 2.1 6.2 3-1 6.2 6.2 1.1 6.2 - 1.1 - 3-1 7.3 - 2.1 V 3.0 1.1 t 1 2.1 4.1 1.1 4 -2 1.1 4.1 3.1 - 2.1 2.1 1.1 4.1 5.2 6.2 1.1 2.1 V 2.3 1.1 . 1 1 - 4.1 2.1 2.1 1.1 5.2 2.1 - 4-1 2.1 1.1 6.2 5.2 2.1 4 -2 2.1 V 2.3 2.1 3 1 5.2 ? 5.2 4 .2 1.1 4 -2 5.2 ? ? - _ - - - - ? rv 2.5 4 .2 2.1 3 1 4 -2 - 2.1 2.1 2.2 5-2 - 3.1 3.1 5-2 5.2 - 4 .2 2.1 - rv 2.4 1.1 1 1 3.1 1.1 3-1 2.1 2.1 4.1 2.1 2.1 1 .! IV 1.3 1.1 _ 2.1 _ 4.1 2.1 1.1 1.1 - 1.1 - - 1.1 2.1 - 2.1 2.1 IV 1.1 1.1 1 1 6.2 _ . _ 1.1 2.2 2.1 1.1 3.1 _ 3-1 - 3-1 - 2.1 i n 1.3 _ _ 3-1 3.1 3.1 3.1 1.1 1.1 3.1 2.1 - - - 1.1 - 2.1 HI 1.2 3.1 - 1 1 2.1 - 4 -2 1.1 4 .2 - 3.1 - - - - 2.1 - - 2.1 - i n 1.2 1.1 1 1 _ - 3.1 _ 3.1 - 1.1 1.1 3.1 i n .9 - _ 1.1 2.1 1.1 2.1 2.1 2.1 1-.+ 2.1 - - 1.1 1.1 1.1 - i n .8 - 4.1 1 1 - 1.1 1.1 1.1 1.1 - 1.1 1.1 - - - 2.1 - 1.1 2.1 - i n 8 i n .6 1.1 - 2 1 - - 2.1 1.1 1.1 - 1.1 - 1.1 - - - 3-1 - - i n .6 _ + .+ _ - 2.1 - 1.1 - + .+ - 1.1 1.1 1.1 - 1.1 - HI .6 1  .6 _ _ 1 1 - 1.1 2.1 1.1 - 1 .1 1.1 - - - - - - - - 1.1 1  • 4 - - - - 1.1 - - 1.1 1.1 - 1.1 1.1 - - 2.1 - - 1.1 1  .4 2.1 2.1 2.1 2.1 2." 2.1 2.1 3 2 2.2 1.1 1.1 3-1 1.1 2.1 1.1 6.2 5-2 2.1 4.2 2.2 1.1 2.2 2.1 1.1 l . l - 1.1 4.2 7.3 1.1 6.3 3.1 6.2 _ 5-2 4.1 5.2 5.2 5.2 3.1 + .+ 6.3 3.1 1.1 5-3 V 3.7 5.2 3.1 2.1 2.1 1.1 3.2 1.1 3.1 1.1 4 .2 1.1 3.1 1.1 1.1 3-2 1.1 1.1 1.1 V 2.0 4 -2 3.1 1.1 3.2 4 .2 - 2.1 - 2.1 5.2 7.3 6.2 - 2.1 6.3 1.1 7.3 IV 2.8 3.1 _ 2.1 _ 3.1 3.1 5-2 4 .2 1.1 5.2 3 .2 1.1 1.1 5-2 3.1 2.1 - rv 2 .2 2.1 4 .2 - 1.1 3-2 2.1 2.1 - . - 4.2 4 .2 3-1 - - 6 .3 2.2 i n 1.7 2.1 1.1 5-2 5-2 - 3 -2 2.1 2.2 7 .3 -11 1.5 2.1 1.1 1.1 4-1 2.1 5.2 2.1 2.1 2.1 - 1.1 4.2 i n i n 1.0 .7 _ 1.1 _ _ - 3.2 _ 1.1 - 5.3 - 3.2 - - 2.1 1.1 - 1  .8 - - - - 2.1 - 5.2 3.2 - 4.2 - - 1.1 - 4.2 - - 1  .8 jrOTAL SPECIES (incl.sporadic a) 32 47 58 35 48 52 43 58 42 43 41 53 33 28 39 35 45 46 38 | Sporadic species C layer 17(2.1) D layer (Bryophytas) (Lichenea) 111 Senecio yukonenais 124 Abietljiella abletina 17(1.1) 137 Lophoaia porphyroleuca 101(1.1) 149 Poltigara malacea 17(2.2) 112 Carex podocarpa 26(2.1) 125 Ceratodon purpureua 17(*.t) 138 Sphagnum terea 101(3.1) 150 Bhiaocarpon geographicum 17(-..-f) 113 Equisetum arvense 28(1.1) 126 Cynodontium strumirerua 17(1.1) 139 Scapania lrrigua 99(3.1) 151 Solorlna crocea 17I-..-0 114 Polygonum alaskanum 28(+.+) 127 Tetraplodon mnloldea 17(1.1) 140 Pohlia nutans I13(+.t) 152 Cetraria plnaatri 26(- . .») 115 Astragalus umbellatus 60(1.1) 128 Tortula rural i a "(• . • ) 141 Lophozia obtuaa 118(1.1) 153 Cetraria sepincola 26(*.-f) 116 Castilleja pallida 60(1.1) 129 Bartramla ithyphylla 26(2.2) 142 Ptilium crieta-caatrenala 118(6.2) 154 Cetraria nlgrlcaacens 60(1.1) 117 Saxifraga bronchialia 60(1.1) 130 Campyllun polygamua 26(*.») 143 Sphagnun baltioum 134(2.1) 155 Paralalia stygla 74(1.D 118 Alnus crispa 78(1.1) 131 Cynodontium polycarpon 28(1.1) 144 Nardia sp. 139(2.2) 156 Cladonia furcate 99(>.») 119 Poa glauca 86(2.1) 132 Hypnum revolutum 26(1.1) 145 Oneophorus tenollua 139(1.1) '57 Ochrolochla inaequatula 99(4.2) 120 Selaginella sibirlca 86(1.1) 133 AmblyeMgium Juratzkonua 55<».+ ) 146 Lophoaia attenuate 161(1.1) 158 Solorlna aaccata 99(».») 121 Rubus chamaemorus 101(*.») 134 Sphagnum recurvuffl 60(4.2) 147 Lophoaia excise 161(3.1) 159 Ochrolechia upsallensla 113(1.1) 122 Valeriana capitata 113(».*) 135 Conostomua tatragonum 66(1.1) 148 Lopho2la quadrlloba 161(1.1) 160 Pertusaria panyrga 113(1.1) 123 Ago ser i s aurantlaca 118(2.1) 136 Dicranowelsla criapula 66(3.1) 161 Umbilicaria cylindrica 113(1.*) Hanson (1953), C h u r c h i l l (1955) and Spetzman (1959) have described a s i m i l a r v e g e t a t i o n type i n the f o o t h i l l / s u b a l p i n e r e gion i n northern Alaska, Two v a r i a t i o n s are recognized and are discussed below. (a) v a c c i n i o - betulosum glandulosae (fruticulosum) (Figure 15) P l o t s sampled i n t h i s v a r i a t i o n are present on east f a c i n g slopes i n the Canoe Lake v i c i n i t y between 1100-1900 f t . At Trout Lake they have more north-e r l y exposures and are between 550 T1270 f t . P h y s i o g r a p h i c a l l y these s i t e pro-f i l e s are hummocky and e i t h e r convex or s t r a i g h t . The hummocks are mostly elongated and l y i n g p a r a l l e l w i t h the d i r e c t i o n of the slope. Tli^y are be-tween 1-6 f t long and 1-2 f t high and are i n d i c a t i v e of s o i l movement. Ex-posed rocks are not present i n any of the analyzed p l o t s . Snow d u r a t i o n i s approximately 9 months, however, t h i s v a r i e s due to the m i c r o r e l i e f w i t h i n each p l o t . During the autumn and winter the depressions between the hummocks are f i l l e d w i t h snow. This snow p r o t e c t s the ve g e t a t i o n from d e s i c c a t i n g winter winds. The hummock tops are f r e e of snow before the depressions, and occasion-a l l y show signs of w i n t e r exposure, which i s i n d i c a t e d by sparse v e g e t a t i o n cover and small patches o f bare s o i l . Snow remains longer on the east f a c i n g slopes at Canoe Lake because they are pro t e c t e d by the higher ridges from the p r e v a i l i n g northwest winds. The west f a c i n g slopes are u s u a l l y f r e e of snow at l e a s t a week before those opposite. Drainage i s more r a p i d on the hummocks, g i v i n g r i s e to a much t h i c k e r a c t i v e l a y e r , than the depressions. Subsurface meltwater channels are present at the lowest p o i n t s under the hummocks. I t i s not unusual f o r i c e to be present d i r e c t l y under the depression v e g e t a t i o n i n mid-summer. Although the Va c c i n i o - Betuletum glandulosae i s considered to be the c l i m a t i c 'climax' the s o i l p r o f i l e s do not always i n d i c a t e a great degree of genetic development. Downslope movement of m a t e r i a l s causes a burying of organic matter w i t h i n the mineral h o r i z o n s . P r o f i l e s show grea t e r development w i t h i n the hummocks than i n the depressions. 57 Figure 15. V a c c i n i o - Betuletum glandulosae (fruticulosum) on g e n t l e east f a c i n g dip slope (1400 f t ) east of Canoe Lake. Carex lugens present on the mounds. (Photo by K r a j i n a ) The major v a s c u l a r species of t h i s v a r i a t i o n are present on the more mesic sides of the hummocks. Constant species a s s o c i a t e d with Betula glandulosa and Vaccinium uliginosum are Carex lugens, Ledum decumbens and Vaccinium v i t i s - i d a e a . A d d i t i o n a l important species i n c l u d e Arctostaphy1os a l p i n a , Polygonum b i s t o r t a , A r c t a g r o s t i s l a t i f o l i a , Anemone n a r c i s s i f l o r a and Empetru'ii hermapb.roditum. An i n d i c a t i o n of the degree of drainage on the hum-mock tops and t h e i r more exposed p o s i t i o n i s the presence of Hierochloe a l p i n a , S a l i x p h l e b o p h y l l a , Dryas o c t o p e t a l a , Lupinus a r c t i c u s and Antennaria neoalaskana. In the moister depressions S a l i x p u l c h r a i s the major v a s c u l a r species and because of i t s more s h e l t e r e d p o s i t i o n sometimes a t t a i n s shrub height (over 6 i n c h e s ) . The tussock forming Eriophorum vaginatum i s present i n only three p l o t s and i s not t r e a t e d s e p a r a t e l y i n the synth e s i s t a b l e s be-cause of i t s high c o r r e l a t i o n w i t h the f r u t i c u l o s u m . Lichens are l e s s abundant due to the more compact h a b i t of the v a s c u l a r f l o r a . On the dry hummock tops C e t r a r i a c u c u l l a t a , C_. n i v a l i s and Thamnolia  v e r m i c u l a r i s are g e n e r a l l y present. Mosses are rare on the more exposed micro-h a b i t a t s . They are, however, abundant on the more mesic sides and i n c l u d e such species as Aulacomnium turgidum, Hylocomium splendens, Polytrichum juniperinum, Dicranum elongatum JJ. scoparium, JJ. groenlandicum and Sphagnum g i r g e n s o h n i i . S c a t t e r e d throughout these mosses are s e v e r a l l i c h e n s such as C e t r a r i a i s l a n d i c a , Cladonia m i t i s , C_. r a n g i f e r i n a , C_. amaurocraea, Stereocaulon alpinum, D a c t y l i n a  a r c t i c a and Nephroma expallidum. Bryophytes dominate the depression micro-h a b i t a t s and c e r t a i n species c h a r a c t e r i s t i c of moister h a b i t a t s are present. They i n c l u d e Sphagnum g i r g e n s o h n i i , P t i l i d i u m c i l i a r e , Aulacomnium pa l u s t r e and Dicranum angustum. (b) v a c c i n i o - betulosum glandulosae (fruticosum) (Figure 16) This v a r i a t i o n i s present i n depressions on w e s t e r l y and n o r t h e r l y exposed * upper slopes and on s h e l t e r e d slopes at lower e l e v a t i o n s . Shrub s i z e (1/2-2 f t ) B e t u l a glandulosa are c h a r a c t e r i s t i c o f t h i s type. In the Canoe Lake region p l o t s were analyzed at between 1100-1900 f t e l e v a t i o n and at Trout Lake between 380-660 f t . S i t e p r o f i l e s on the lower slopes are e i t h e r s t r a i g h t or s t r a i g h t -hummocky. The upland depressions correspond to the snow-patch h a b i t a t s described by P o r s i l d (1951), where owing to the p r e v a i l i n g winds, a snowdrift forms regu-l a r l y each w i n t e r g i v i n g p r o t e c t i o n to the u n d e r l y i n g p l a n t cover. P l o t s o f t h i s type are g e n e r a l l y small (100 sq. m. or l e s s ) . At both Trout Lake and Canoe Lake these s i t e s are e a s i l y recognized i n the s p r i n g by t h e i r p e r s i s t e n t snow cover, and the l a c k of snow on surrounding communities. These depressions are a r e s u l t o f mass downslope movement of r o c k s , s o i l and vegetation ( g e n e r a l l y i n the spring) due to excessive drainage water and f r o s t heaving. The sampled p l o t s on the lower slopes show signs of mass movement that appear r e l a t e d to e i t h e r s o l i f l u c t i o n or thermokarst a c t i v i t y . The l a t t e r r e l a t i n g to the exposure o f p e r e n n i a l l y frozen ground by s p r i n g f l o o d waters along r a i s e d creek 59 banks. Due to the more s h e l t e r e d p o s i t i o n of these p l o t s a p r o t e c t i v e snow cover does not appear to be necessary to guarantee the s u r v i v a l o f shrub spe-c i e s . Drainage i s more r a p i d i n t h i s v a r i a t i o n than i n the f r u t i c u l o s u m and can be r e l a t e d te the r e d u c t i o n i n hummock type m i c r o r e l i e f . S o i l p r o f i l e s are shallower i n the depressions because of past disturbance. On the lower slopes and creek banks p r o f i l e s are g e n e r a l l y deeper, however, depth to perma-f r o s t seldom exceeds 65 cm. Figure 16. V a c c i n i o - Betuletum glandulosae (fruticosum) depression on lower slope (1200 f t ) northwest corner of Canoe Lake. Bordered by f r u t i c u l o s u m hummocks elongated and l y i n g p a r a l l e l with the d i r e c t i o n of the slope. (Photo by K r a j i n a ) Vascular p l a n t s a s s o c i a t e d w i t h the shrub Be t u l a glandulese and Vaccinium uliginosum i n the fruticosum as constants are Ledum decumbens, Vaccinium v i t i s -idaea, Arctostaphylos a l p i n a and S a l i x glauca. Due to the r e d u c t i o n i n s i z e or lack of hummock mic r o - r e l i e f .several species of major importance i n the f r u t i c u l o s u m , although present i n the fr u t i c o s u m , are of minor importance. They i n c l u d e Carex lugens. Anemone n a r c i s s i f l o r a , Polygonum.bistorta and A ^ ^ A S I ^ l t i 5 i a t i f o l i a . Shading by shrubs might be an a d d i t i o n a l f a c t o r i n t h e i r reduced presence and low coverage values. In the depressions h a b i t a t s Sphagnum species are absent, probably due to the d r i e r c o n d i t i o n s . They are present on the lower slopes where drainage i s l e s s r a p i d due to shallow slope g r a d i e n t s . The presence of Rhytidium rugosum suggests that drainage, once the thaw has commenced, i s more r a p i d than on surrounding s i t e s . Other major bryophytes present are Aulacomnium turgidum, Hylocomium splendens, Dicranum elongatum and Polytrichum juniperinum. The occurrence and abundance of l i c h e n species i s reduced p a r t i a l l y on account of shading and p o s s i b l y because of the di s t u r b e d c o n d i t i o n of the s i t e s . C e t r a r i a c u c u l i a t a i s abundant i n only two p l o t s (101 and 161), both of which are at lower e l e v a t i o n . The range i n e l e v a t i o n between the highest and lowest elevated p l o t s i n -di c a t e s that a good winter, snow cover i s provided. On more n o r t h e r l y exposed slopes the community i s present i n depressions while on more s o u t h e r l y exposed slopes the fruticosum i s seldom exposed to d e s i c c a t i n g winds. Species d i v e r s i t y i s g r e a t e r i n the V a c c i n i o - Betuletum glandulosae than i n any other community where Betula glandulose i s a major c o n s t i t u e n t . These s i t e s never experience as r a p i d a drainage as do those h a b i t a t s on the upper s l o p e s , nor as r e s t r i c t e d a drainage as those on the lower s l o p e s , s o i l moisture c o n d i t i o n s are more mesic than sub-mesic. Permafrost l i e s c l o s e to the surface ( w i t h i n 60 cm). Diurnal, changes i n temperature and r e l a t i v e humidity are never so great as on the upper slopes and r i d g e tops or i n the wetland s i t e s . The highest temperature r e -corded at Canoe Lake i n 1965 was 85°F i n p l o t 17. S o i l temperatures are gen-e r a l l y warmer and probably allow a great degree of m i c r o b i a l a c t i v i t y because of t h e i r more mesic c o n d i t i o n . However, slow downslope movement of m a t e r i a l s 61 probably r e s t r i c t s increased s o i l development. 5. Betulo - Chamaemoretum Table 6 fa) § (b) The Betulo •- Chamaemoretum i s c h a r a c t e r i s t i c of p o o r l y drained lower slopes with seepage o c c u r r i n g throughout the vegetative.season. These s i t e s are not waterlogged, although, a low hummocky m i c r o r e l i e f i s always present. The p l o t s g e n e r a l l y have a more southerly exposure and range i n e l e v a t i o n from 1075-1475 f t . Slope gradients are g e n t l e or moderate (0-20°). Many of the s i t e s are o l d drainage pathways with the remainder r e s t r i c t e d to more e a s t e r l y exposed slopes. Snow cover i s moderately deep due to the s h e l t e r e d low elevated p o s i t i o n and the presence of shrubs. Duration i s approximately 9-9 1/2 months. The physio-graphy and f l o r i s t i c composition of t h i s a s s o c i a t i o n i s s i m i l a r to the A l n u s  c r i s p a type along the C o l v i l l e R i v e r , Alaska and described by C h u r c h i l l (1955). . Two subassoeiations are recognized, the b e t u l o - chamaemoretosum with Alnus c r i s p a absent, and the alnetosum c r i s p a e . (a) b e t u l o - chamaemoretosum This s u b a s s o c i a t i o n i s found on a v a r i e t y of h a b i t a t s a l l of which are re-garded as h y g r i c . S i t e types range from o l d drainage pathways to lake edges. Sampled p l o t s were on s o u t h e r l y exposed slopes between 1075-1190 f t . Micro-r e l i e f i s g e n e r a l l y s t r a i g h t to concave hummocky with a g e n t l y s l o p i n g gradient (0-10°). Snow du r a t i o n i s estimated to be 9 months and i s considered moderately deep (no a c t u a l measurements are a v a i l a b l e ) . S o i l s are shallow w i t h l i t t l e p r o f i l e development. Permafrost i s present w i t h i n 25 cm of the surface and as deep as 42 cm (measured August 11th, 1966). While drainage i s not r e s t r i c t e d , the h y g r i c c o n d i t i o n that p r e v a i l s e s p e c i a l l y i n the mineral s o i l leaves these s i t e s s u s c e p t i b l e to f r o s t heaving during the s p r i n g and autumn. This c o n d i t i o n gives r i s e to the hummocky m i c r o r e l i e f present i n a l l p l o t s . Constant species i n t h i s s u b a s s o c i a t i o n are Betula glandulosa, Rubus chamaemorus, Vaccinium uliginosum, V. v i t i s - i d a e a , Ledum decumbens, Empetrum Table No. 6 b Plot No. Plot size (m^ ) Date Analyzed PLOT DATA Locality Elevation (ft) PHYSIOGRAPHY Land form Relief: Profile Expo sure (°) Slope gradient (°) CLIMATE Snow duration STRATA COVERAGE (%) Bi layer B2 layer C layer D layer Moss Lichen Betulo - Chamaemoretum betulo - ohamaemoretosum alnetosum orispae 106 51 47 46 152 123 167 112 181 176 100 50....... 12/8 5/7 4/7 4/7 23/7 22/8 28/7 17/8 13/8 11/8 1965 1965 1965 1965 1966 1965 1966 1965 1966 1966 CL CL CL CL CL CL CL CL CL CL 1075 1100 1125 1125 1150 1190 1175 1250 1350 U75 River .Old Depre - Drain- Lake Old Drain- Exposed Exposed Expo sed bank creek ssion age way edge creek age way slope slope slope ...Straight... Cnv Stg Flat ' Stg' Cnv Stg-Hum Stg-Hum Cnv-Hum 120 180 135 135 315 90 200 90 90 70 5 3 4 4 0 10 20 19 10 20 30 30 40 70 70 90 30 50 75 70 20 30 70 65 90 40 85 90 100 85 90 60 100 95 90 80 95 95 100 85 90 45 5 2 3 15 10 3 3 2 SOIL Drainage Hygrotope Depth of active layer (cm) 42 35 .Poor to Moderate. Hygric 30 ' 30 40 26 28 .Moderate. . . Hygric. . 30 20 43 CHEMICAL ANALYSIS No.of samples Organic layer 0M 86.0 70.5 72.5 50 3 71.8 79 7 68.0 94-9 82.0 74.4 N% 1.12 1.19 1.38 1 05 1 .21 84 1.48 1 .01 1.39 1.29 C/N 45.1 36.3 30.1 27 9 34-3 66 2 26.2 56.0 34.2 33.5 P ppm 32 5 5 4 18 16 15 26 16 38 Na • 9 .88 1.09 94 • 96 68 • 93 .64 .98 .93 K .88 .6 .87 36 1.08 72 .67 1.23 • 93 • 94 Ca 13.6 29.5 7.9 8 6 25-2 18 6 20.6 15.5 26.4 23.8 Mg 5.1 7.2 3.1 3 5 5-1 2 4 5.8 6.8 3.9 3-4 CEC 116.5 148.0 134.3 138 0 72.4 120 5 65.6 140.5 132.3 92.9 PH 4.2 5.0 4-2 4 8 4.1 4 2 4-7 3.8 4-7 4.5 No.of samples Organic -Mineral layer OM N% C/N P ppm Na K Ca Mg CEC PH 31.2 1 .08 18.7 3 .89 .17 3.5 • 9 58.6 4-5 1 34-5 1.09 18. A 18 1 .12 • 51 18.7 2.8 53.4 • 4-2 1 17.5 .62 16.4 16 • 55 .25 10.9 2.5 29.3 4-4 No.of samples Mineral layer 2 2 1 1 2 2 OM 8.2 3.7 0.0 7.0 5-4 9.8 N% .32 .13 .06 .26 .21 .31 C/N 14.1 15.7 0.0 15.6 13.7 18.2 P ppm 7 12 4 4 5 22 Na .58 • 55 .47 • 56 .82 .81 K .15 .1 .3 • 24 .38 .6 Ca 3.3 4-4 3.6 10.3 7.4 10.1 Mg 1.1 .6 .3 .6 25.2 24.3 CEC 28.8 41.8 3.6 34.7 4.9 4-4 PH 4.7 5-5 4.9 4.8 Table No. Q a Betulo - Chamaemoretum Number of P l o t s E l e v a t i o n ( f t ) P l o t No. P l o t size (m' betulo ~ chamaemoretosum 106 51 Ul 152 123 100 1075 1100 1125 1125 1150 1190. alnetosum c r i s p a e • 1 2 3 A 167 112 181 176 ; - . 5 0 1175 1250 1350 U75 C l a y e r Sporadic species C l a y e r 53 Luzula rufescens 54 S e l a g i n e l l a s i b i r i c a 55 Carex rotundata 56 Eriophorum a n g u s t i f o l i u m 57 Senecio yukonensis 58 V i o l a e p i p s i l a 59 Oxycoccus. microcarpus 60 Pyrola secunda . 61 Hierochloe a l p i n a 62 Cassiope tetragona 63 Carex vaginata D l a y e r (Bryophytes) 64. Lophozia e x c i s a Avg. B l a y e r l a y e r Constancy, Cover 1 Alnus c r i s p a 1 - _ 7.3 7.3 7.3 7.3 II 2.8 2 S a l i x pulchra 2 - - 6.2 6.2 .-i 6.2 - 4.2 5.2 3 S a l i x glauca 2 5.2 - - 1.1 - . 2.1 - - II .8 4 Spiraea beauverdiana 2 4.2 - - 3.1 - - 1.1 - 5.3 • 5 Betula glandulosa 2 8.3 - - 7.3 - 7.3 7.3 7.3 5-2. 4.2 ' Betula glandulosa 7 3 .1 6.2 7 4 .1 7 7 ? ? ' V . 5.8 6 Rubus chamaemorus 8.2 2.1 8.2 4^1 5.1 7.2 5 - T 6.'2 2 J 5.'l. . V 5.2 7 Empetrum hermaphroditum - 3.1 8.3 2.1 6.2 7.2 7.2 6.2 3.1 3.2 V 4.5 8 Vaccinium uliginosum 3.1 3 .1 5.2 2.1 5-2 4.2 6.2 5.2 6.2 5.2 V ' 4 . 4 9 Ledum decumbens 2.2 2 .1 3 .1 3.1 4 . 2 6.2 6.2 6.2 4.2 4.2 V ' 4 . 0 10 Vaccinium v i t i s - i d a e a 1.1 2.1 2.1 3 .1 5.2 6.3 . 5.2 4.1 4.2 1.1 . V 3.3 11 P e d i c u l a r i s lapponica 1.1 1.1 1.1 1.1 2.1 1.1 4.1 1 .1 + .+ - V 1.3 S a l i x pulchra - 4.1 3.1 7 7 - 7 - 7 7 IV 3.4 12 A r c t a g r o s t i s l a t i f o l i a 1.1 1.1 - 1 j - 2.1 1.1 3.1 1.1 3^1 ' IV 1.3 13 P e t a s i t e s f r i g i d u s +.+ + .+ - 1.1 1.1 2.1 - 2 .1 - 5.1 IV 1.3 14 Polygonum b i s t o r t a 1.1 - 1.1 - 3.1 - 3.1 2.1 1.1 1.1 IV 1.2 Spiraea beauverdiana 7 - 1.1 7 - - 4.2 7 - 7 I I I 1.8 15 Lycopodium annotinum - - 4.2 - 1.1 - 4.2 - 6.2 '3.2 II I 1.8 16 Carex lugens - 5 .1 - + .+ - - 3.1 + .+ 4.2 II I 1.4 17 Andromeda p o l i f o l i a - - 2.1 - 1.1 - 3.1 + .+ 2 .1 I I I .9 18 Eriophorum vaginatum - 1.1 1.1 - 2.1 - 1.1 2.1 - - I I I .7 19 P e d i c u l a r i s l a b r a d o r i c a + .+ 1.1 + .+ 1.1 1-.1 - - - - - I I I .5 20 Poa a r c t i c a 1 .1 - - - - + .+ 3.1 - - 2.1 II .8 21 Arctostaphylos a l p i n a - - - - - - 1.1 + .+ 1.1 - II .3 22 Luzula wahlenbergii 2.1 - - - - - - 3.1 ' I .5 23 Linnaea b o r e a l i s - - - - - - 3.1 - 2 .1 - I .5 24 S t e l l a r i a c i l i a t o s e p a l a - - - 2.1 - - - - - 2 .1 I .4 25 Calamagrostis canadensis' 3.1 - - - - - - + .+ - - I .4 26 P i n g u i c u l a v i l l o s a - - 1.1 - + .+ - - - - - I .2 27 Equisetum arvense 1.1 - - - - - - I .2 28 Carex a q u a t i l i s + .+ • - - + .+ - - - - - . I .2 D l a y e r (Bryophytes) 29 Sphagnum g i r g e n s o h n i i . _ 6.3 8.3 8.4 9.4 8.3 6.2 4 . 2 IV 5.6 30 Sphagnum recurvum 7.2 7.3 +.+ - 7.3 + .+ - 2.1 7.3 3.1 .IV 3.5 31 Polytrichum juniperinum 1.1 3.1 1.1 4.2 4.2 4 - 2 5.2 1.1 - - IV 2.3 32 Sphagnum rubellum 1.1 4 . 2 1.1 - 5.3 1.1 - 1.1 3.2 - IV 1.6 33 Aulacomnium turgidum - 5-2 - - 1 .1 2.1 1.1 + .+ 1.1 1.1 IV 1.2 34 Aulacomnium p a l u s t r e 2.1 2.1 2.1 4.2 5.2 - - - - - I I I 1.5 35 Hylocomium splendens - - - 1.1 3.2 2.1 - 2.2 6.2 - i n 1.4 36 Dicranum scoparium - - 3 .1 1.1 - - 3.2 1.1 2.1 1.1 II I 1.1 37 Lophozia kunzeana 1.1 - 1.1 1 .1 1 .1 - + .+ 1.1 - - I I I .6 38 Polytrichum commune 3 . 2 - 2.1 - - - 2.1 - - 4.2 II 1.1 39 C a l l i e r g o n straraineum - - - + .+ - - - II .5 40 Calypogeia trichomahis - - - - 1.1 3.2 - 1.1 - - II .5 41 Dicranum angustum - - - - 3.2 - - 1.1 + .+ I I .5 42 Drepanocladus uncinatua - - - 2 .1 - . - - - 1.1 II .4 43 Tomenthypnum n i t e n s 2.1 - - 1 .1 - 1.1 - - - - II .4 44 Sphagnum lenense 4 . 2 - - - - - - 1.1 - - I .5 45 Sphenolobus minutus - - - - - 2-1 - 1.1 - - .1 .3 (Lichenes) 46 C e t r a r i a c u c u l l a t a 1 .1 _ _ 2.1- + .+ + .+ - I I .5 47 P e l t i g e r a scabrosa 2.1 - - - 2 .1 - - + .+ - - I I .5 48 Cladonia amaurocraea - - - - 3.2 - + .+ - - II .5 49 C e t r a r i a p i n a s t r i 2.1 - - - - - - 1 .1 - 1 .1 II .4 50 Cladonia r a n g i f e r i n a - - - - 2.1 1.1 - - + .+ - II ' .4 51 Stereocaulon alpinum - - - - 2.1 + .+ - - - 1.1 II .4 52 C e t r a r i a i s l a n d i c a - - - - - 3 .1 + .+ - - I .4 I TOTAL SPECIES ( i n c l . s p o r a d i c s ) 30 24 25 31 41 30 25' 37 31 271 46(2.1) 65 P o h l i a nutans 46(1.1) 79 Ceratodon purpureus 176(+.+) 47(3.1) 66 Tetraplodon paradoxus 46(+.-r) 80 C a l l i e r g o n c o r d i f o l i u m ' 181(1.1) 51.(5.1) 67 Sphagnum balticum 47(8.3) 81 Cephalozia leucantha 181(+.+) 51(2.1 68 Sphagnum l i n d b e r g i i 106(3.2) 106(2.1) 69 Sphagnum ri p a r i u m 106(4.2) (Lichenes) 46(1.1) 123(+.+ ) 70 Dicranum elongatum 112(1.1) 82 Parmeliopsis ambigua 152(3.1) 71 Dicranum fuscescens 123(4-2) 83 P e l t i g e r a aphthosa 46(+.+) 176(2.1) 72 Gymnocolea i n f l a t a 123(1.1) 84 C e t r a r i a s e p i n c o l a 46(1.1) 181(1-1) 73 Cephalozia bicuspidata1>2(1.1) 85 Lecidea sp. 106(1.1) 181(1.1) 74 Dicranum mllhlenbeckiil 52(1.1) 86 P e l i g e r a cahina 51 C+.+ ) 181(2.1) 75 Lophozia v e n t r i c o s a 152(+.+) 87 P e l t i g e r a malacea 112(+.+) 76 M y l i a anomala 152(+.+ ) 88 Cladonia m i t i s 123(1.1) 77 Nardla s c a l a r i s 152(1.1) 89 P e l t i g e r a p o l y d a c t y l a 123(1.1) 46(1.1) 78 Sphagnum aongstroemiil52(3.2) 90 C e t r a r i a r i c h a r d s o n i i 152(2.1) 91 Thamnolia v e r m i c u l a r i s 152(1.1) .92 Cladonia f i m b r i a t a 152(1.1) 62 hermaphroditum and P e d i c u l a r i s ^ p j i o n i c a . The woody species (B. glandulosa —• uliginosum, V. v i t i s - i d a e a and L. decumbens) present i n the b e t u l o -chamaemoretosum have broad amplitudes of t o l e r a n c e . T h e i r presence i n these p o o r l y drained h a b i t a t s i s r e l a t e d to t h e i r a b i l i t y to root only i n the or-ganic h o r i z o n thereby a v o i d i n g the excess moisture present i n the mineral horizons. A s s o c i a t e d species w i t h high constancy and coverage values i n c l u d e S a l i x p u l c h r a , P e d i c u l a r i s l a b r a d o r i c a , P e t a s i t e s f r i g i d u s and A r c t a g r c s t i s l a t i f o l i a . Two d i f f e r e n t i a l species are present, they are P e d i c u l a r i s l a b r a d o r i c a and P i n g u i c u l a v i l l o s a . The high constancy and coverage of Rubus chamaemorus suggests an a v a i l a b l e supply of calcium i n the organic l a y e r , and that considerable d r y i n g out occurs i n the hummocks. Lichen presence and coverage i s very lew with no species present i n more than h a l f of the sampled p l o t s . Sphagnum g i r g e n s o h n i i , S. recurvum, S_. rube Hum, Aulacomnium p a l u s t r e and Polytrichum juniperinum are the dominant bryophytes. The presence of Sphagnum species and Aulacomnium. p a l u s t r e i n the depressions i s an i n d i c a t i o n of the h y g r i c c o n d i t i o n of the h a b i t a t s , (b) alnetosum c r i s p a e F l o r i s t i c a l l y t h i s s u b a s s o c i a t i o n i s s i m i l a r to the b e t u l o - chamaemoretosum except f o r the presence c f Alnus c r i s p a . The t a l l Alnus c r i s p a p l o t s are d i s -t i n g u i s h e d by t h e i r dark b l u i s h green colo u r . They occur at low e l e v a t i o n s , between 1175-1475 f t , on steeper slopes (10-20° gradients) and are u s u a l l y present below exposed felsenmeer. During the e a r l y part of the summer the sampled p l o t s were very wet. Seepage i s g e n e r a l l y continuous throughout most of the summer. The permafrost t a b l e i s h i g h , never l e s s than 43 cm. from the s u r f a c e , so that seepage would appear to have l i t t l e a f f e c t on i t s p o s i t i o n . Surface m i c r o r e l i e f i s g e n e r a l l y hummocky with moisture c o n d i t i o n s s i m i l a r to those of the previous s u b a s s o c i a t i o n . Snow accumulation i s g r e a t e r i n these h a b i t a t s and i t s b u i l d up during the winter i s no doubt aided, by the shrubs themselves. As the m a j o r i t y of these p l o t s are on east f a c i n g slopes w i t h t h e i r sides ex-posed, snow cover p r o t e c t s the Alnus c r i s p a from d e s i c c a t i n g w i n t e r winds. The t a l l well-developed Alnus c r i s p a shrubs protect, the other woody spe-c i e s present i n the community and. produce a favourable environment f o r t h e i r ad-d i t i o n a l growth. Be t u l a glandulose, S a l i x pulchra.. S. glauca and Spiraea beauverdiana a l l a t t a i n shrub height, (under 2 f t ) i n t h i s a s s o c i a t i o n . Species composition i n the C l a y e r i s s i m i l a r to that of the b e t u l o - chainaemoretosum with - Rubus chamaemorus having high coverage values i n every p l o t . Shading by the shrubs appears to affect, the d i s t r i b u t i o n of s e v e r a l s p e c i e s , r e s t r i c t i n g the establishment of P i n g u i c u l a v i l l o s a and P e d i c u l a r i s l a b r a d o r i c a . Several species present i n the a s s o c i a t i o n have higher constancy values and coverage values i n t h i s s u b a s s o c i a t i o n , they are Lycopodiun. ann.otinum, Ar c t o s t a p h y l o s a l p i n a , Andromeda p o l i f o l i a Carex lugens and Linnaea borea.lis. The D l a y e r i s again dominated, by Sphagna. However, Dicranum scoparium and Aulacomnium turgidum are present on the d r i e r hummock su r f a c e s . The absence of Aulacomnium p a l u s t r e probably r e f l e c t s the b e t t e r drainage on these steeper more elevated slopes. Lichen cover i s very meagre. 6. Betulo - Eriophoretum v a g i n a t i Table 7 (a) (b) Hanson (1953) has termed t h i s a 'complex' i n r e c o g n i t i o n of the c l o s e as-s o c i a t i o n of microcommunities, however, they were not separated i n h i s s y n t h e s i s t a b l e s . In the present study only one a s s o c i a t i o n i s recognized. This communit type may occur i n both upland and lowland areas of the subalpine zone where drainage i s poor and moisture c o n d i t i o n s remain semi-hydric throughout, the sum-mer. They are not r e s t r i c t e d to any p a r t i c u l a r s l o p e , but are exposed to a l l the c a r d i n a l p o i n t s . Snow dur a t i o n i s estimated to be 9 months. Accumulation i s never deep due to the g e n e r a l l y low m i c r o r e l i e f and exposed p o s i t i o n of the p l o t s . This i s r e f l e c t e d i n the low growth of species present, i n t h i s as-s o c i a t i o n . Drainage i s poor and at times r e s t r i c t e d . -Table Mo f jj Plot No. Plot size (m2) Date Analyzed 93 Betulo - Eriophoretum vaginati eriophoretosum vaginati 20/7 U/7 1965 1965 12/7 1965 5/7 1965 12/7 1966 54 . 1 0 0 . 6/7 1965 24/8 1965 2/7 1965 5/7 1965 13/8 1966 21/6 1965 salicetosum reticulatae 27 .100. 18/7 19/6 16/6 1965 1965 1954 71 100 14/7 1965 PLOT DATA Locality Elevation (ft) TL 500 TL 575 TL 625 CL 1080 CL 1100 CL 1100 CL CL 1130 1130 CL 1150 CL 1500 CL 1850 TL 650 CL 1750 CL 1850 TL 500 PHYSIOGRAPHY Land form Rolief: Prof i le Exposure ( ° ) Slope gradient ( ° ) Raised ..Exposed., polyon slope ....Cvx-Hum 45 45 90 2 2 5 Raised ..Exposed.. Old polygon slope creek Hum Stg-Hum .-Hummocky.. 25 270 90 0 0 4 10 1 Exposed Raised slope polyon Cvx-Hum Hum 70 0 10 0 Exposed Drain-slopes age way Stg-Hum Cvx-Hum 90 70 5 15 Exposed Dried Exposed slope up lake slope ....Cnv-Hum... Stg-Hum 200 0 270 8 2 10 Slope depression Cvx-Hum U5 CLIMATE Snow duration .9 months. 9 months STRATA COVERAGE {%) Bg layer C layer D layer 100 85 80 95 95 40 95 70 95 90 60 100 95 95 100 Moss 50 65 55 50 65 90 75 85 40 85 70 70 60 50 50 Lichen 20 10 5 5 20 5 55 10 15 5 15 15 10 10 10 SOIL Drainage Hygrotope Impeded Hydric to semi-hydric. Moderate Hygric to semi-hygric Impeded Hygric Depth of active layer (cm) CHEMICAL ANALYSIS No.of samples Organic layer No.of samples Organic -Mineral layer No.of samples Mineral layer 25 20 28 35 30 27 28 30 30 30 33 28 30 30 35 2 1 1 3 1 3 2 1 3 2 1 2 2 2 1 0M 7 4 . 9 55 .8 59 .3 82.8 72.6 62.1 76 .3 84.5 8 5 . 6 88.4 77.2 34 -2 6 2 . 8 5 7 . 9 69 .5 t>% 1 .26 .77 1 .05 1.39 1.09 .88 .84 1.89 1.28 1.76 1 .12 1.16 1.01 1.86 1.05 C/N 3 0 . 6 4 2 . 0 32 .8 36.6 38.6 51.8 55.5 25-9 39-4 29.5 4 0 . 0 17 .4 3 7 . 2 18 .2 38 .4 P ppm 10 10 19 11 28 •5 17 5 32 32 0 8 15 10 21 Na .67 . 7 9 .8 .91 • 74 .81 .66 1 .34 1 .02 1 .12 1.0 .63 .96 .81 . 7 4 K . 6 8 • 73 1 .01 • 55 • 74 .62 .76 .99 1 .43 .87 . 3 . 3 . 9 .48 .98 Ca 8.1 7.9 2 1 . 0 7.9 16.3 11.7 13 .5 1 3 . 9 8 . 1 3 32 .9 4.5 29 .5 27 .0 2 6 . 6 11 .3 Mg 2.0 4.3 9.2 3.7 • 9 3 - 4 4-1 4-4 1.6 3.3 1 .0 1 0 . 8 1 5 - 3 6.6 4 - 3 CEC 124-0 82.3 98.3 160.0 84 -3 107.9 80.8 193 .0 129.7 138 .0 139 .0 7 4 . 3 1 3 4 . 5 138.0 84.1 pH 4-1 4.3 4 . 8 4-4 5 -9 4.8 3.7 4-3 3 .7 4-2 4.5 6 . 3 6 .1 5 - 8 4 . 2 0M 39-4 33.1 t>% . 5 6 . 4 2 C/N 42.1 45.7 P ppm 20 2 Na .9 . 9 3 K .82 .2 Ca 15 .6 4 .7 Mg 4-7 .9 CEC 50.8 76.3 pH 4.0 1 1 •} 4-5 1 0M 19.8 21 .4 4 - 3 16.4 . 6 18.3 2.7 1 .9 K% .22 .63 . 1 3 • 52 .1 1.32 .09 .07 C/N 52.2 19 .7 19.1 18.7 3.5 8 . 0 17 .4 12 .2 P ppm 3 11 9 2 3 2 7 5 Na . 5 7 .56 .76 •42 . 5 4 .88 • 92 .89 K .21 • 35 . 0 9 .08 .07 .13 • 34 • 14 Ca 3 . 3 12 .7 11 .3 3.2 5 - 4 1.7 7.4 1.2 Mg 1.5 3 - 9 2 . 3 . 7 . 6 .2 1.0 .1 CEC 38.1 5 7 . 4 3 0 . 5 49-5 13 .0 76 .3 12.2 23 .9 PH 4 - 9 5 .3 4-4 4-9 5-2 3 . 8 4.5 4 - 8 7 a Number of Plots Betulo - Eriophoretum vaginati eriophoretosum vaginati sal ice to sua reticulatae 1 2 3 4 5 6 7 8 9 10 11 93 69 59 52 138 54 130 40 48 160 34 1 a 3 87 27 21 .,. ,100 500 575 625 1080 1100 1100 1130 1130 1150 1500 1850 650 1750 1850 2 Eriophorum vaginatum 3 Betula glandulosa 4 Ledira decumbens 5 Vaccinium vltis-idaoa 6 Bapetrum hsrmaphrodltum 7 Vaccinium uliginosum 8 Carex lugens 9 Rubua chamaemorus 10 PediculariB lapponica 11 Salix pulchra 12 Polygonum blatorta 13 Arctoataphyloa alpina 14 Salix reticulata 15 Andromeda pollfolla 16 Pingulcula villoaa 17 LuzuLa nivalis 18 Arctagrostis latlfoLla 19 Petasites frigidua 20 Carax rotundata 21 Cassiope tetragona 22 Dryas octopetala 23 Salix glauca 24 Lagotis glauca 25 Poa arctica 26 Stellaria clliatosepala 27 Pyrola grandiflora 28 Hierochloe alpina 29 Pedicularis lanata 30 Salix phlebophylla 31 Oxytropia maydelllana 32 Saxifraga punctata 33 Luzula confusa 34 PediculariB labradorica 35 Juncus biglumls 36 Senecio atropurpureus 37 Saxifraga hieracifolia 38 Polygonum viviparum 39 Draba nivalis 40 Eutrena edwardsii 8.3 6.2 7.2 9.2 6.2 3.1 3.1 5.2 5-2 4.1 3.1 2.1 1.1 1-1 4-2 1.1 - 2.1 2.1 2.1 2.1 2.1 1.1 1.1 1.1 1.1 - 4-1 4.1 - 5-2 1.1 2.1 1.1 - 1.1 2.1 1.1 3.1 3.1 4-1 3.1 - 2.1 1.1 1.1 1.1 1.1 2.1 1.1 - 2.1 2.1 1.1 4.1 5.2 2.1 1.1 1.1 2.1 2.1 1.1 2.1 2.1 -1.1 1.1 1.'l l j 41 Aulacomnium turgidum 42 Sphagnum la nan aa 43 Sphagnum ruballum 44 Dicranum anguBtum 45 Sphenolobus minutus 4.6 Polytrichum juniporinum 47 Sphagnum rocurvum 48 Hylocomiuo Bplendans 49 Dicranum elongatum 50 Sphagnum girgensohnii 51 Dicranum acoparium 52 Sphagnun balticum 53 Dicranum fuscescsna 54 Ptilidiun ciliare 55 Calypogela trichomanls 56 Rhacomitrium lanuginoeum 57 Dicranum groenlandieum 58 Tonenthypnum nitens 59 Aulacomnium palustre 60 Rhytidiun rugoaum 61 Polytrichum c 62 Lcphozla sp. 63 Lophozia quadriloba 64 Dicranum muhlenbeckii 65 Drepanocladua uncinatus 66 Hypnisn callichroum 67 Lophozia ventricosa (Lichenes) 68 Cetraria cucullata 69 Cladonia mitis 70 Cetraria islandlca 71 Cladonia ranglferina 72 Peltigera aphthosa 73 Cladonia amaurocraea 74 Dactylina arotioa 75 Peltigera acabroaa 76 Thamnolia vermicularis 77 Cetraria nivalis 78 Peltigera polydactyla 79 Peltigera canina 80 5tereocaulon elpiniun 81 Cladonia graeilia 82 Alectoria ochroleuca 83 Stereocaulon rivulorum 84 Cladonia furcata 85 Cetraria rlchardsonii 86 Cladonia chlorophaea 87 Nephroma expallidum 88 Alectoria nitidula 89 Alectoria nigricans 90 Cladonia gonecha 1.1 3-1 2.1 1.1 2.1 1.1 2.1 3.1 3.1 2.1 2.1 4 .2 5.2 5.2 2.1 V 2.5 5.2 4 .2 5.2 5.2 7 .3 7 .3 7 .3 8 .3 1.1 9.4 6 .3 - - 1.1 IV 4 . 3 2.1 4 -2 2.1 3-2 6.2 - - - - 3-1 3-2 - 1.1 2.2 2.2 IV 1.9 - 2.1 - 3.2 - - 5.3 1.1 4 .2 1.1 4 -2 + .+ 2.1 2.1 rv 1.7 1.1 - 1.1 - 1.1 + .+ 2.1 - - + .+ 4 .2 1.1 +.+ 1.1 + .+ IV 1.0 3.J 1.1 2.1 - 2.1 + .+ 1.1 - 1.1 - - + .+ 1.1 rv .9 _ 4.2 5-2 - - 6.2 + .+ 5-2 - - 2.1 - 3.1 1.1 i n 1.8 1.1 2.1 _ _ - 1.1 _ _ - - - 5.2 5-2 4 .2 5-2 i n 1.6 3 .2 1.1 1.1 2.1 2.1 1.1 1.1 2.1 1.1 5-2 • i n 1  .9 1.0 3.1 2.1 - - 1.1 - - 5-2 - - - - - 1  .8 2.1 _ - - 3-2 - 2.1 - 1.1 1.1 - - _ 1  .6 3-1 - 3.1 - 3.2 1  .6 2.1 3-2 1.1 2.1 + .+ +.+ 2.1 3.1 - 6.3 1.1 3.1 1.1 2.1 + .+ 1.1 1.1 V 1.8 + .+ 1.1 1.1 - 4 .2 - 2.1 1.1 1.1 - - rv .9 1.1 T .+ 1.1- + .+ 1.1 1.1 1.1 1.1 rv .8 3.2 _ 1.1 3-2 - 4 -2 + .+ 2.1 _ - - 1.1 i n 1.0 1.1 2.1 1.1 _ - 1.1 1.1 _ 2.1 1.1 3.1 1.1 i n .9 - + .+ +.+ - 2.1 - 4 -2 - - 1.1 1.1 1.1 1.1 1.1 - i n .9 2.1 1.1 + .+ 2.1 - 1.1 1.1 + .+ - 1.1 - + .+ - i n .7 1.1 1.1 1.1 + .+ - 1.1 1.1 _ - 1.1 - + .+ i n .5 2.1 1.1 - +.+ 1 1 1.1 - 1.1 1.1 1  1  .5 .3 TOTAL SPECIES (incl sporadica) 35 36 32 26 36 24 30 32 26 31 41 46 56 45 Sporadic species 91 Anemone naroisaiflora 92 Arenaria arctica 93 Lupinus arctlcua 94 Arnica alpina 95 Equisetum arvanse 96 Pyrola secunda 97 Ranunculus nivalis 98 Valeriana capltata 99 Salix arbutifolla 100 Anemone parviflora 101 Saussurea angustifolia 102 Carex montanenBia 103 Carex rariflora 104 Viola eplpalla 105 PedLcularis arctica 106 Spiraea beauverdlana 107 Pedicularis capitata D layer (Bryophytea) (Ldchenea) 21(1 1) 108 Philonotia fontana 21 (+ ») 124 Cladonia coccifera 21U.+ ) 21(1 D 109 Brachytheclum sp. 27(+ • ) '25 Ochrolechia inaequetula Z7(+.+ ) 21 (• + ) 110 lophozia qulnquedentata 27<* •O 126 Icoadophila ericetorum 34(-.+ > 27(1 1) 111 Polytrichum plllferum M* *) 12? Ochrolechia frigida 34(+.+ ) 27{+ +) 112 Cyrano co lea inf lata 52(2 1) 1) 126 Partusaria dactylina 34(3.2) 27(1 1) 113 Lcphozla obtusa 69(1 129 Partusaria panyrga 34(+.+) 27(+ +) 114 Pogonatum alpinum 93(1 1) 130 Cetraria sap in cola 48( +. + ) 27(1 1) 115 Lophozia.alp©atria 93(1 1) 131 Cornlcularia divergens 4S(+.-0 34(1 1) 116 Pohlia nutans 93(1 1) 132 Cetraria chrysantha 54(2.1) 40(1 1) 117 Ceratodon purpureua 130(5 2) 133 Co tr aria pinastri 7K+.+ ) 40(1 1) 118 Tetraplodon paradoxus 130(1 1) 134 Cladonia uncial!a 87(1.1) 52(1 1) 119 Dierana11a subulata 138(1 1) "135 Sphaarophorus globosus 93(2-1) 52(1 1) 120 Har pan thus acutatus 138(+ •0 136 Cetraria laevigata 1301+.+) 52(+ •> 121 Sphagnum obtusum 138(2 1) 59(1 1) 122 Lophoiia attenuata 180(1 1) 71(1 87(1 1) 1) 123 Sphagnum aongatroemii 180(1 1) The l o c a l i z e d i n s t a b i l i t y of t h e . s o i l where.Betulo - Eriophoretum v a g i n a t i dominates gives r i s e to two major m i c r o h a b i t a t s . These h a b i t a t s are a d i r e c t r e s u l t of f r o s t a c t i o n ( c o n g e l i t u r b a t i o n ) i n the mineral s o i l which produce a. hummock-depression m i c r o r e i i e f . No attempt has been made to date i n a r c t i c North America to analyze these micro-communities s e p a r a t e l y and to d i s t i n g u i s h microenvironmental d i f f e r e n c e s . The depth to the upper surface of permafrost v a r i e s w i t h surface m i c r o r e i i e f . The a c t i v e l a y e r i s deeper under the hummocks than the depressions. This i s r e l a t e d to increased d r a i n -age i n the hummocks and the i n s u l a t i n g p r o p e r t i e s of the moss l a y e r i n the de-pr e s s i o n . Ice or frozen ground are i n v a r i a b l y present w i t h i n 10-15 cm of the surface under the moss l a y e r i n the depression, whereas i n the hummocks peren-n i a l l y frozen ground i s from 20-35 cm below the su r f a c e . Two subassociations are d i s t i n g u i s h e d i n t h i s subalpine zone, the eriophoretosum v a g i n a t i and the salicetosum r e t i c u l a t a e . (a) eriophoretosum v a g i n a t i (Figure 17) The eriophoretosum v a g i n a t i covers l a r g e areas on the lower slopes of the subalpine zone. I t occurs on a v a r i e t y of h a b i t a t s , i n c l u d i n g o l d drainage pathways, o l d creek beds, r a i s e d polygons and exposed slopes. Sampled p l o t s i n the Canoe Lake area are g e n e r a l l y between 1100-1500 f t e l e v a t i o n and be-tween 500-625 f t at Trout Lake. Slope gradients vary from 2-23° with the majority of the p l o t s having an e a s t e r l y exposure. A l l areas where the eriophoretosum v a g i n a t i i s present have a very broken topography due to ex-cessive f r o s t a c t i o n . D e t a i l e d s t u d i e s by Hopkins and Sigafoos (1951) and Sigafoos (1951) have described i n d e t a i l the tussock forming Eriophorum  vaginatum and i t s r o l e i n d i f f e r e n t i a l f r o s t heaving i n wet mineral s o i l . Moisture c o n d i t i o n s vary from h y g r i c to semi-hydric. Drainage waters pass q u i c k l y over the upper s l o p e s , but due to a reduced slope gradient at the lower l e v e l s water movement i s l e s s r a p i d . While the f r e e water i s not completely impeded as i n the wetland areas i t i s slowed down co n s i d e r a b l y by the hummock (tussock) m i c r o r e l i e f that p r e v a i l s and the undulating surface of the perma-f r o s t t a b l e . I.'here the slope gradients are steeper the hummocks tend to bo more elongated and l i e p a r a l l e l with the slope i n d i c a t i n g downslope movement. On very shallow slopes and f l a t surfaces the hummocks appear at random, tend-ing to be t a l l e r and o c c a s i o n a l l y with bare s o i l among them. The bare mineral s o i l plays a major r o l e i n the development of these t a l l hummocks i n areas of r e s t r i c t e d drainage. The r a i s e d polygon s i t e s occur i n areas that arc b e t t e r drained than those on which other tussock groups are formed. Figure 17. Betulo - Eriophoretum v a g i n a t i b e t u l o - eriophoretosum v a g i n a t i tussocks surrounded at the base by dead leaves and culms. Dark brown areas are Sphagnum lenense w i t h s c a t t e r e d Rubus chamaemorus. (Photo by Lambert) Snow cover and d u r a t i o n d i f f e r s i n the eriophoretosum v a g i i \ a t i because o f the hummock-depression m i c r o r e l i e f . Snow- i s packed i n t o the depressions during 66 the w i n t e r and i s u s u a l l y a week behind the hummock snow i n thawing. T o t a l d u r a t i o n of snow cover i n the Canoe Lake area f o r t h i s s u b a s s o c i a t i o n i s e s t i -mated at 9 months. Eriophorum vaginatum i s by f a r the most important species with very high cover values i n a l l sampled p l o t s . Tussock density was c a l c u l a t e d to be be-tween 5-8 per square meter. The f a c t i s , however, the tussocks c o n s i s t of more dead than l i v i n g leaves and. culms. The o l d e r tussocks are n e a r l y spher-i c a l with the o l d dead leaves and culms crowded t o the outer surface. The tussocks are s u b s t r a t e f o r s e v e r a l species of v a s c u l a r p l a n t that, are common on t u r f hummocks: constants i n c l u d e Betula glandulosa, Vaccinium uliginosum a n c* —• v i t i s - i d a e a . A d d i t i o n a l species w i t h high constancy are Rubus chamacmorus. Empetrum hermaphroditurn, P e d i c u l a r i s lapponica and Carex lugens. A l l these SPCCXfeS 3.TG 1*0 oted i n the organic-mineral l a y e r . Small clumps of S a l i x pjalchra are o c c a s i o n a l l y present i n the moist depressions along with Andromeda p o l i f o l i a and P i n g u i c u l a v i l l o s a . Sphagnum appears to be the pre-f e r r e d s u b s t r a t e f o r these two species. I t should be pointed out that no Eriophorum vaginatum dominated p l o t s were analyzed where the t a l l development, of tussocks and the exposed unstable mineral s o i l , r e s t r i c t e d establishment of many a d d i t i o n a l v a s c u l a r p l a n t s . In p l o t s v/here small amounts of bare s o i l are present Juncus b i g l u m i s i s always .present. Sphagnum lenense, S_. g i r g e n s o h n i i , S. rubellum, Calypogeia trichomanis and Dicranum angustum are common bryophytes on the moist tussock bases and i n the depressions. An i n d i c a t i o n o f the slow movement of f r e e drainage water i n i s o l a t e d areas of s e v e r a l p l o t s i s the presence of Sphagnum b a l t i c u m and Aulacomnium p a l u s t r e . On the d r i e r more open tussocks are such mesophytic species as Dicranum elongatum, D. groenlandicum and Sphenoiobus minutus. Lichen coverage i s very sparse w i t h only C e t r a r i a c u c u l l a t a present on the l a r g e r more open tussocks. S c a t t e r e d among the Sphagna are D a c t y l i n a a r c t i c a , C e t r a r i a i s l a n d i c a , Cladonia m i t i s , C_, r a n g i f e r i n a , C_. amaurocraea, P e l t i g e r a aphthosa and P. scabrosa, a l l w i t h high constancy but low cover values. C l o s e l y a l i g n e d with t h i s s u b a s s o c i a t i o n i s a community i n which Alnus c r i s p a forms a shrub (under 2 f t ) l a y e r . This community appears t r a n s i t i o n a l between the B e t u l a - Chamaemoretum and the Betulo - Eriophcretum vaginatum. I t i s included i n the s y n t h e s i s t a b l e s of the l a t t e r a s s o c i a t i o n . (b) s a l i c e t o s u m r e t i c u l a t a e (Figure 18) The salicetosum r e t i c u l a t a e occurs only on the upper slopes where d r a i n -age though poor never appears completely r e s t r i c t e d . Compared with the lower slope eriophoretosum v a g i n a t i , moisture c o n d i t i o n s i n these h a b i t a t s are con-s i d e r e d to be more-hygric and never semi-hydric. This s u b a s s o c i a t i o n i s poor-l y represented i n t h i s area of the subalpine zone, communities being analyzed from only three l o c a l i t i e s . T h e i r m i c r o r e l i e f i s always hummocky w i t h e i t h e r s t r a i g h t or concave p r o f i l e s . Slope gradients are shallow (2-10°) with e i t h e r north or northwest exposures. The analyzed p l o t s are present at e l e v a t i o n s be-tween 1750-1850 f t at Canoe Lake and at 650 f t at Trout Lake. A l l s i t e s appear to r e c e i v e some p r o t e c t i o n from the surrounding slopes. Vegetation on these bordering slopes belongs to e i t h e r the Dryadion or the Betulo - Ledetum decumbentis types. Melt water from these r a p i d l y drained slopes i s channelled i n t o the salicetosum r e t i c u l a t a e . Snow cover i s as long (9 months) as on the lower elevated Eriophorum vaginatum dominated slopes. However, compared to the surrounding s l o p e s , snow p e r s i s t s as much as three weeks longer. Consequently, while v e g e t a t i v e growth gives a c h a r a c t e r i s t i c green c o l o u r to the bordering slope communities, t h i s community appears l i g h t brown i n mid-June, being n o t i c e a b l e from a considerable d i s t a n c e . The t h i c k n e s s of the a c t i v e ^ l a y e r i n these upland s i t e s i s probably the same as on the lower slopes. Measurements i n t h i s s u b a s s o c i a t i o n were made i n e a r l y J u l y whereas i n the eriophoretosum v a g i n a t i they were made i n l a t e J u l y and mid-August. Height and d e n s i t y of tussocks are s i m i l a r to those on the lower slopes, 15-20 cm high and between 5-8 tussocks per square meter. 68 Figure IS. Betulo - Eriophoretum v a g i n a t i salicetosum r e t i c u l a t a e , northwest f a c i n g slope (1350 f t ) , b o r d ering s p a r s e l y vegetated slope dominated by Dryas o c t o p e t a l a . (Photograph taken June 16/65 by Lambert) Dwarf heath species that are constant i n the eriophoretosum v a g i n a t i are present here but with reduced constancy and coverage values. Rubus chamaemorus, P e d i c u l a r i s lapponica, Andromeda p o l i f o l i a and P i n g u i c u l a v i l l o s a are absent at these higher e l e v a t i o n s . Several species i n t h i s s u b a s s o c i a t i o n that are g e n e r a l l y a s s o c i a t e d w i t h the sub-xer i c upper slopes are present as character-i s t i c constants. They i n c l u d e S a l i x r e t i c u l a t a , Dryas octo p e t a l a and Poa a r c t i c a . A d d i t i o n a l species a s s o c i a t e d w i t h higher e l e v a t i o n s o f the subalpine zone and present as sporadics are: Sal i x p h l e b o p h y l l a , Lupinus a r c t i c u s , A r e n a r i a a r c t i c a and Oxytropis maydel l i a n a . The occurrence o f such species as S a l i x r e t i c u l a t a , S a x i f r a g a h i e r a c i f o l i a and L a g o t i s glauca are i n d i c a t i v e of increased q u a n t i t i e s of a v a i l a b l e calcium and the more calcareous nature of the s o i l s i n these s i t e s . 69 An i n d i c a t i o n of the r e d u c t i o n i n a v a i l a b l e moisture and the d r i e r con-d i t i o n of these p l o t s was the absence of Sphagnum lenense and S. g i r g e n s o h n i i and the low presence of S_. rube Hum and £>. recurvum. Species such as Tomenthypnum n i t e n s and P t i l i d i u m c i l i a r e have replaced the Sphagnum species. The a s s o c i a t e d l i c h e n s are s i m i l a r to those of the eriophoretosum v a g i n a t i . S o i l i n s t a b i l i t y i s c h a r a c t e r i s t i c of t h i s s u b a s s o c i a t i o n , however, down-slope movement i s l e s s obvious because of the shallow slope g r a d i e n t s . No m i c r o r e l i e f patterns such as r i n g s , n e t s , garlands, s t r i p e s and ridges were found a s s o c i a t e d w i t h the Betulo - Eriophoretum v a g i n a t i . This a s s o c i a t i o n would appear unique and, as suggested by P o r s i l d . (1951), seems r e s t r i c t e d to those u n g l a c i a t e d regions of western a r c t i c North America. Hanson (1953) could f i n d no c l o s e resemblance with h i s Alaskan, cottongrass - sedge - dwarf heath type to communities i n Scandinavia. Aquatic p l a n t communities The aquatic v e g e t a t i o n i n the s u b a l p i n e / f o o t h i l l zone occur only i n , or around, lakes. P o r s i l d (1951) has d i s t i n g u i s h e d two types of f r e s h water vege t a t i o n : ponds and l a k e s , and brooks and r i v e r s . Plant, communities around lakes are u s u a l l y arranged i n c o n c e n t r i c bands roughly corresponding to water depth. Because of the s c a r c i t y of lakes i n t h i s u n g l a c i a t e d region of western a r c t i c Canada, few s i t e s were found f o r a n a l y s i s . Of the two recognized aquatic l i f e forms, rooted submerged and rooted emergent,'only the l a t t e r were found i n the two study areas. • In the Alaskan f o o t h i l l s , Spetzman (1959) found that water depth seldom exceeded two feet f o r the emergent aquatics. This emergent type plays an important r o l e i n the o b l i t e r a t i o n of lakes through the accumulation of peat which r e s u l t s i n r i s i n g permafrost l e v e l s and r e s t r i c t e d drainage. 1. Arctophiletum f u l v a e Table 8 (a) § (b) (Figure 19) The Arctophiletum f u l v a e i s poorly represented i n the two study areas, only four p l o t s were analyzed'in the Canoe Lake area. A l l four s i t e s were Table No. 8 b Arctophiletum fulvae Plot No. 116 171 160 159 Plot size(m ) 16 16 16 16 Date Analyzed 20/8 10/8 26/7 25/7 1965 1966 1966 1966 PLOT DATA Locality CL CL DL DL Elevation 1045 1050 1100 1100 PHYSIOGRAPHY Land form Relief: P r o f i l e Exposure (°) .Flat 0 0 250 0 Slope gradient 0 0 1 0 CLIMATE Snow duration STRATA COVERAGE {%) 8* months C layer 100 85 80 90 D layer Moss 20 5 95 25 PLOT COVERAGE (%) by water 20 10 95 25 SOIL Drainage Hygrotope .Impeded. ..Hydric. Depth of active layer .Undetermined. CHEMICAL ANALYSIS No.of samples Organic -Mineral layer No.of sample s Mineral layer 1 1 OM N% 2.8 .06 4-6 .21 C/N 27.0 12.7 P ppm 16 7 Na .68 .78 K .11 .22 Ca 2.3 7.3 Mg .3 .9 CEC 19.5 11.0 pH 4.9 5.2 3 1 1 1 OM 1.7 1.3 - .9 Wo .16 .13 .04 • 05 C/N 6.9 5.8 - 10.4 P ppm 7 6 2 5 Na .85 .82 .83 .9 K • 29 .25 .23 .22 Ca 4.2 1.6 1.7 1.9 Mg .7 .6 - -CEC 17.1 17.3 33.0 32.6 PH 4.7 4.6 4-3 4-4 Table No. 8 a Number of P l o t s P l o t No. P l o t s i z e (m 2) E l e v a t i o n C l a y e r Arctophiletum f u l v a e 1 2 3 . A 116 171 160 159 16 16 16 16 1045 1050 1100 1100 Sporadic species C l a y e r 11 Carex a q u a t i l i s 160(1.1) 12 Ranunculus p a l l a s i i 159(3.1) 1 A r c t o p h i l a f u l v a 1 0.5 9 A 6.2 9 4 2 H i p p u r i s v u l g a r i s 1.1 1 1 7.1 A 1 3'Senecio congestus • - 1 1 1.1 1 1 A Epilobium p a l u s t r e - 6.1 5 1 5 Ranunculus g m e l i n i i - 2. 1 1.1 6 Cardamine p r a t e n s i s 1.1 2 1 -D l a y e r (Bryophyte s) 7 Drepanocladus aduncus _ 9.3 5 2 8 Bryum sp. 2.1 - 3. 1 9 C a l l i e r g o n c o r d i f o l i u m - 2. 1 1.1 10 Epilobium p a l u s t r e - 6.1 6. 1 TOTAL SPECIES ( i n c l . s p o r a d i c s ) 7 6 10 S \ Constancy V V IV III III III III III III III D l a y e r (Bryophytes) 13 Mnium punctatum 116(5-2) 1A Marchantia polymorpha 116(+.1) 15 Polytrichum commune 116(2.1) 16 Sphagnum d u s e n i i 160(3-2) Avg. Cover 8.5 3.2 .8 2.8 3.5 1.2 .8 3.0 70 between 1050-1100 f t e l e v a t i o n . Two are from the shore o f Canoe Lake, the other two are from Di v i d e d Lake s i x miles east o f Canoe Lake. An example o f the r o l e of t h i s a s s o c i a t i o n i n lake o b l i t e r a t i o n i s w e l l i l l u s t r a t e d at Divided Lake where accumulated organic m a t e r i a l has d i v i d e d the lake and cut o f f the major drainage o u t l e t from the l a r g e s t body of water. In lakes that are d r y i n g up a super-saturated c o n d i t i o n p r e v a i l s throughout the growing season. G e n e r a l l y , the extensive f i b r o u s root mat and peaty l a y e r i s i n s u f -f i c i e n t to support the weight of a man. Snow accumulation i s considerable around the lake shore due to the deep cut banks and i t s d u r a t i o n i s estimated to be 8 1/2 months. Drainage waters from the surrounding slopes and the melti n g lake i c e r e s u l t i n a r i s e i n water l e v e l , approximately 1-1 1/2 f t , during the thaw p e r i o d . Consequently, during the e a r l y part o f the summer the Arctophiletum f u l v a e i s submerged. By the end o f the summer, with a drop i n water l e v e l , only the outer l i m i t s o f the community remains i n standing water around the lake edge. Figure 19. Lake shore v e g e t a t i o n , Canoe Lake. In the foreground Arctophiletum f u l v a e , bordered by bands o f Eriophorum scheucjvzeri_. Cut bank supports S a l i x p u l c h r a . (Photo by Kr a j i n a ) 71 The Arctophiletum f u l v a e i s f l o r i s t i c a l l y poor with only eight species present. A r c t o p h i l a f u l v a and H i p p u r i s ' v u l g a r i s are the only constant spe-c i e s . Other species a s s o c i a t e d with these emergent aquatics are Senecio congestus, Epilobium p a l u s t r e Ranunculus g m e l i n i i and Cardamine p r a t e n s i s . In the D l a y e r there are no l i c h e n s present. Bryophytes are sparse i n the lake shore communities. This can probably be r e l a t e d to the scouring a f f e c t of loose lake i c e along the shore during break-up. The p r e v a i l i n g north west winds jam the loose i c e i n t o the south end of Canoe Lake. P l o t 171, l o c a t e d at the south end,had an estimated bryophyte coverage of only f i v e percent, while p l o t 116 at the northeast end, had twenty percent. Major mosses i n c l u d e Drepanocladus aduncus, C a l l i e r g o n c o r d i f o l i u m and Mnium punctatum var. elatum, the l a s t taxon i s able to withstand more prolonged f l o o d i n g . In two p l o t s (159 and 160) at D i v i d e d Lake, Epilobium p a l u s t r e seedlings covered as much as t h i r t y percent of the f i b r o u s mat surface. S e m i - t e r r e s t r i a l p l a n t communities S e m i - t e r r e s t r i a l h a b i t a t s , composed of wet sedge meadows, cover approxi-mately f i f t e e n percent of the ground surface i n the two study areas. Wet sedge meadow species grow up to the edge of open water on one extreme and are mixed with the tussock type of the lower slopes at the other extreme. These h a b i t a t s , where the water t a b l e i s a t , near or above the ground surface are considered as h y d r i c to semi-hydric. The a s s o c i a t i o n s described f o r these hab-i t a t s , along w i t h t h e i r c h a r a c t e r i s t i c combination of s p e c i e s , must be con-s i d e r e d only t e n t a t i v e . Several types are i n s u f f i c i e n t l y represented w i t h a few communities appearing to be t r a n s i t i o n a l between a s s o c i a t i o n and subassoeia-t i o n s . The v e g e t a t i o n i s r e l a t i v e l y , poor i n species w i t h few d i f f e r e n t i a l and/ or constant species present. Lichens are absent i n a l l but one p l o t . Present, however, are a number of woody species w i t h broad amplitudes of t o l e r a n c e . These are found wherever small hummocks and ridges are formed as a r e s u l t of f r o s t heaving. 72 The wet sedge meadows are c h a r a c t e r i s t i c of poo r l y drained wetlands and depressions, such as o l d lake s i t e s and drainage pathways. Free surface water i s u s u a l l y present, but only i n small pools, i n these s i t e s during the l a t t e r p a r t of the summer. Major v e g e t a t i o n u n i t s may be d i s t i n g u i s h e d between s i t e s where there i s f r e e f l o w i n g drainage water during the s p r i n g and summer, and where there i s no drainage o u t l e t and Water l o s s i s p r i m a r i l y through evapora-t i o n . 1. Eriophoretum a n g u s t i f o l i i Table 9 (a) § (b) The Eriophoretum a n g u s t i f o I i i dominated p l o t s are not r e s t r i c t e d to the wetlands of lower e l e v a t i o n s but are a l s o present on the upper slopes i n nar-row exposed drainage pathways. In more pro t e c t e d s i t e s on the slopes shrub species f o r c e out the Eriophorum a n g u s t i f o l i u m . In the f l a t wetlands E_. a n g u s t i f o l i u m dominates exposed s i t e s where there i s l i t t l e w i n ter snow ac-cumulation. Water r u n o f f i s q u i c k l y l o s t . Snow, however, i s g e n e r a l l y present, on the surrounding communities f o r s e v e r a l more weeks. P e r e n n i a l l y frozen ground i s c l o s e r to the surface on the upper slopes than on the lower and i s r e l a t e d to the amount of f r e e f l o w i n g drainage water passing over the s i t e s . Two su b a s s o c i a t i o n s have been d i s t i n g u i s h e d and are r e l a t e d to e l e v a t i o n and amount of f r e e f l o w i n g drainage water. They are the eriophoretosum a n g u s t i f o l i i and the salicetosum pulchrae. (a) eriophoretosum a n g u s t i f o l i i (Figure 20) This s u b a s s o c i a t i o n develops i n drainage pathways on the lower slopes or on lake edges where slope gradients are minimal. Water movement, while not r a p i d , i s continuous throughout most of the summer. Supplementary seepage oc-curs during the l a t t e r part of the ve g e t a t i v e season. Snow cover during the winter i s seldom more than a foot deep and f r e e f l o w i n g drainage water removes i t while snow remains on the neighbouring areas. Permafrost l e v e l s are lower because of the surface and seepage water present during the summer. Table No. 9 b Eriophoretum a n g u s t i f o l i i , eriophorosum a n g u s t i f o l i i No.of samples Mineral layer OM N% C/N P ppm Na K Ca Mg CEC pH 1 3.1 .15 13.5 10 • 55 • U 3-5 .6 26.7 4 . 5 2.3 .13 9.4 .^69 .17 4.9 .6 19.1 4.0 4 . 2 1.19 3.3 8 .68 .23 6.1 1.8 14.3 4 . 7 salioosum pulchra Plot No. 72 107 42 154 49 - 63 . 57 38 120 Plot size (m2) 25 25 25 25 25 25 25 25 25 Date Analyzed 14/7 12/8 2/7 23/7 5/7 13/7 6/7 2/7 21/8 1965 1965 1965 1966 1965 1965 1965 1965 1965 PLOT DATA Loc a l i t y TL CL CL DL CL TL CL CL CL Elevation ( f t ) 485 1050 1075 1140 1145 i 730 1060 1175 1750 PHYSIOGRAPHY Land form Depre- .Drainage. . Lake Drainage Old Depre - ..Drainage.. ssion pathway edge pathway creek ssion pathway Reli e f : P r o f i l e Cnv. F l a t F l a t Cvx. ...Straight. Expo sure ( 0) 0 90 135 0 0 90 70 45 90 Slope gradient ( ) 0 2 0 0 0 2 5 13 10 CLIMATE STRATA COVERAGE (%) B2 layer 100 97 70 C layer 98 90 95 90 70 45 90 D layer 0 2 5 35 45 80 50 60 96 PLOT COVERAGE (%) by water 3 10 SOIL Drainage Hygrotope ....Hydric to semi-hygric.. Depth of active 31 60 23 44 36 28 24 30 32 layer(cm) CHEMICAL ANALYSIS No of samples 1 1 1 1 2 2 1 Organic layer OM 43.5 71.7 52.3 42.1 73.9 71.4 64-9 \i% • 98 1.05 1.75 .98 1.54 1.01 .92 C/N 25.7 39.6 17.3 25.7 30.0 43.4 4 0 . 9 P ppm 5 31 29 5 4 3 32 Na • 43 .88 • 95 • 43 .9 1.4 .66 K .19 • 55 3.28 . 19 .78 .66 • 44 Ca 4.6 8.3 34.5 4.6 7.9 10.6 11.2 Mg 1.6 1.6 19.6 1.6 3.0 2.1 1.2 CEC 39.4 64.3 83.7 39.4 138.0 122.0 80.9 PH 4.6 4.6 . 7 . 2 4-6 4.9 4-4 4.8 No.of samples 2 1 . 1 1 1 Organic - OM 16.5 23.3 18.8 2T.3- 11.2 Mineral layer U% .31 .28 • 56 .16 .3 C/N 32.7 4.8 19.5 77.2 21.7 P ppm 16 8 8 2 11 Na • 51 .8 .43 .68 .86 K . 09 .11 .24 • 14 .9 Ca 3.8 2 .4 7 .3 2 .7 2 .0 Mg 1.35 • 5 2 .6 .9 .6 CEC 31.8 67.3 41.6 76.5 67 .0 pH 4 . 8 4 . 4 4 . 9 4-9 4.5 c Table No. 9 a Eriophoretum a n g u s t i f o l i i eriophorosum a n g u s t i f o l i i salicosum pulchrae Number of p lo ts P lot No. P lot s ize (m ) E levat ion 1 2 3 4 5 72 107 42 154 49 25 25 25 25 25 485 1050 1075 1140 1145 6 7 8 9 63 57 38 120 25 25 25 25 730 1060 1175 1750 Avg. C-layer Constancy Cover 1 Eriophorum angustifol ium 10.5 9.4 9 4 9.4 9.4 7.3 8.3 7.3 9.4 V 7.7 2 Sa l i x pulchra - - - 5-2 2.1 5.2 9 III 2.0 3 Betula glandulosa - - 1.1 2.1 3.1 2.1 1.1 III .9 4 S a l i x a r b u t i f o l i a 1.1 - - - 3.1 - - 5.2 III .9 5 Vaccinium uliginosum - - +.+ 3.1 2.1 - 1.1 III .7 6 Ledum decumbens - - 1.1 1.1 1.1 1.1 1.1 III • 5 7 Rubus chamaemorus - - 1.1 - 1.1 1.1 2.1 III -5 8 Carex lugens 1.1 - - 2.1 +.+ - - II • 4 9 Vaccinium v i t i s- idaea - - 1.1 - 1.1 + .+ - II • .3 10 Carex aqua t i l i s - 1 1 2.1 - - - - - II .3 11 Eriophorum vaginatum - - - 1.1 - 1.1 - II .2 D layer (Bryophytes) 12 Sphagnum girgensohni i - - - 4-2 7.3 7.3 8.3 ' III 2.6 13 Sphagnum balticum - 1.1 5.2 - 5.2 1.1 - III 1.2 14 Drepanocladus aduncus - 2 1 2.1 3-1 - - - 1.1 III .7 15 Sphagnum lenense - - - 5.2 1.1 5.2 - .11 1.1 16 Aulacomnium palustre - - + .+ 5.2 - - 5-3 II 1.1 17 Polytrichum commune - - 4-2 - 4.2 2.1 - II 1.0 18 Ca l l i e rgon stramineum 1.1 5-2 - - - - 1.1 II .7 19 Polytrichum juniperinum - - - 1.1 4-2 - - I • 5 20 Sphagnum platypbyllum - - - 3.1 - 1.1 - I • 4 21 Sphagnum rubellum - - - 2.1 - - 1.1 I .3 22 Bryum pseudotriquetrum - 1.1 +.+ - - - - I .2 TOTAL SPECIES ( inc l . sporad ics ) 2 5 4 12 14 25 16 U 16 '- Sa l i x pulchra 120(8.3) 33 Polygonum viviparum 120(+ + ) 44 Sphagnum aongstroemii 120(2.1) 34 Arctophi la fu l va 154(1 1) 45 Mnium punctatum 154(3.1) C layer 46 Drepanocladus vernicosus 154(+.+ ) 23 Carex chordorrhiza 49(2.1) D layer (Bryophytes) 47 Drepanocladus exannulatus 120(2.1) 24 Carex rotundata 49(2.1) 35 Sphagnum compactum 38(1 1) 48 Ca l l ie rgon cord i fo l ium 154(4-1) 25 Eriophorum scheuchzeri 49(2.1) 36 Aulacomnium turgidum 38(1 1) .49 Cincl id ium subrotundum 154(1.1) 26 Andromeda p o l i f o l i a 57(1.1) 37 Dicranum angustum 63(1 1) 50 Polytrichum swartz i i 154(6.3) 27 Empetrum hermaphroditum 57(+.+ ) 38 Dicranum elongatum 63(1 1) 51 Atrichum sp. 42(+.+ ) 28 Ped icu la r i s lapponica 57(1.1) 39 Drepanocladus uncinatus 63(1 1) 52 Drepanocladus revolvens 63(+.+ ) 29 Ped icu la r i s sudetica 63(1.1) 40 Sphenolobus minutus 63(1 1) 53 Ca l l ie rgon t r i f a r ium 63(1.1) 30 Sa l i x r e t i c u l a t a 63(2.1) 41 Pohl ia nutans 63 (+ + ) 31 Arc tagrost i s l a t i f o l i a 107(1.1) 42 Campylium polygamum 63 (+ .+ ) D layer (Lichenes) 32 Calamagrostis canadensis 107(1.1) 43 Ph i lonot is fontana 63(1 1) 54 Pe l t igera scabrosa 120(+.+ ) 72 Figure 20. Eriophoretum a n g u s t i f o l i i i n drainage pathway on lower slope (.1100 f t ) , Canoe Lake. Habitat flooded i n e a r l y summer and with continuous water movement throughout the v e g e t a t i v e season. (Photo by K r a i i n a ) Eriophorum a n g u s t i f o l i u m dominates a l l communities and i s the only con-stant s p e c i e s . In the i n i t i a l stages a s s o c i a t e d species are r a r e . L a t e r stages, r e l a t e d to a decrease i n f r e e water movement, see the establishment of sev e r a l woody species and a d d i t i o n a l bryophytes. Mosses are absent or very sparse i n three of the f i v e p l o t s r e p r e s e n t i n g t h i s s u b a s s o c i a t i o n . The dense coverage of E_. a n g u s t i f o l i u m and the r a p i d movement of water r e s t r i c t bryophytes to the le e s i d e s of the sedge clumps. The only species present i n two or more p l o t s are Drepanocladus aduncus, C a l l i e r g o n stramineurn and Bryum pseudotriquetruin. These species are a l l w i t h i n the f l o o d zone o f the drainage pathway. The only Sphagnum species present and able to withstand a degree o f f l o o d i n g i s S. b a l t i c u m . (b) s a l i c e t o s u m pulchrae The salicetosum pulchra i s present on both upper (1750 f t l e v e l ) and lower 74 (between 1060-1175 f t ) slopes. The major d i f f e r e n c e between t h i s subassocia-t i o n and the eriophoretosum a n g u s t i f o l i i i s the r e d u c t i o n i n amount of f r e e f l o w i n g drainage water. On the upper slopes surface water i s l e s s because of the t o t a l area i n v o l v e d . However, on the lower slopes reduction, appears r e -l a t e d to mass movement of surface m a t e r i a l s above the drainage pathways, r e -s u l t i n g i n changes of d i r e c t i o n of flow. Drainage i s then mainly i n the form of seepage. Reduction i n water content leads to increased f r o s t a c t i o n i n the mineral s o i l , g i v i n g r i s e to a hummock-depression type of m i c r o r e l i e f . Snow dur a t i o n i s approximately two weeks longer than the eriophoretosum a n g u s t i f o l i i and the accumulation i s greater because of the presence of small shrubs. A l l four p l o t s r e p r e s e n t i n g t h i s s u b a s s o c i a t i o n have e a s t e r l y exposures. Average depth to permafrost (28 cm) i s l e s s than i n the eriophoretosum a n g u s t i f o l i i (35 cm). Constant species a s s o c i a t e d with Eriophorum a n g u s t i f o l i u m i n c l u d e S a l i x p u l c h r a , Betula glandulosa and Ledum decumbens. A d d i t i o n a l species i n d i c a t i v e of the semi-hydric hummocky c o n d i t i o n s are Vaccinium uliginosum, Rubus chamaemorus, Carex l_ug_ens Vaccinium v i t i s - i d a e a and Eriophorum vaginatum. S a l i x a r b u t i f o l i a i s present i n the wetter areas of p l o t s 63 and 120 between small hummocks. The r e d u c t i o n i n excessive amounts of f r e e flow ring drainage water i s r e f l e c t e d i n the presence and high coverage of Sphagnum g i r g e n s o h n i i and _S. lenense. Sphagnum b a l t i c u m i s present where drainage and seepage waters c o l l e c t . A d d i t i o n a l bryophytes i n c l u d e Polytrichum commune, P_. s w a r t . z i i , P. juniperinum, Aulacomnium p a l u s t r e , . Sphagnum p l a t y p h y l l u m and S. rubeHum. Only one l i c h e n , P e l t i g e r a scabrosa, i s present i n t h i s s u b a s s o c i a t i o n , i n p l o t 120. I t i s f e l t t h a t both subassoeiations are under-represented and that the eriophoretosum a n g u s t i f o l i i i s probably only a phase of the more advanced salicetosum pulchrae. A d d i t i o n a l analyses of t h i s Eriophoretum a n g u s t i f o l i i are needed. 7 5 2. Caricetum a q u a t i l i s Table 10 (a) t] (b) (Figure 21) The Caricetum a q u a t i l i s community dominates areas where drainage r e s t r i c -t i o n i s recent. These areas are g e n e r a l l y small depressions and lakes i n the process of d r y i n g up. Moisture c o n d i t i o n s are considered h y d r i c throughout the v e g e t a t i v e season. Surface topography i s f l a t w i t h l i t t l e evidence of the development of patterned ground. Exposure i s considered to be t o t a l i n a l l p l o t s except three, which r e c e i v e some p r o t e c t i o n from higher ground on at l e a s t one s i d e . Permafrost i s close to the surface (average depth 34 cm) and appears c o n s i s t e n t i n every p l o t . In many cases the organic l a y e r c o n s t i t u t e s part o f the p e r e n n i a l l y frozen ground. Snow cover i s never deep and d u r a t i o n i s estimated to be 8 1/2 months. The a s s o c i a t i o n i s represented by two v a r i a n t s the caricosuni a q u a t i l i s and the salicosum a r b u t i f o l i a e . (a) caricosum a q u a t i l i s The majority of the p l o t s s t u d i e d i n t h i s v a r i a n t are present i n o l d lake beds. The water t a b l e i s high and i n some cases bodies o f f r e e water w i t h a very open type of vege t a t i o n are present. The major source o f water i n these h a b i t a t s i s from mel t i n g snow and seepage from surrounding higher ground. The i n i t i a l causes f o r these lakes d r y i n g up appears to be due to the encroachment of vegetation i n t o the g e n e r a l l y small drainage o u t l e t channels over a pro-longed p e r i o d of time. The only constant species -is Carex a q u a t i l i s . In the p l o t s w i t h open water a common species i s P o t e n t - i l i a p a l u s t r i s . Where the water t a b l e i s a t , or near, the surface s c a t t e r e d culms of Eriophorum scheuchzeri are present. A l -though C. a q u a t i l i s tends, to dominate large areas other Carex species (C. cho r d o r r h i z a and C. rotundata) may be present w i t h high cover values i n a given part of a wet sedge meadow. This i s p o s s i b l e due to the ve g e t a t i v e means of c o l o n i z a t i o n of these Carex species. Also present w i t h low cover values i s S a l i x a r b u t i f o l i a . Bryophyte coverage i s g e n e r a l l y low with small clumps of to f o l l o w page 7 5 Figure 21. O r i g i n a l l y part of Trout Lake t h i s aquatic h a b i t a t has been v i r t u a l l y o b l i t e r a t e d . Carex a q u a t i l i s dominates the s i t e with Carex c h o r d o r r h i z a , C_. rotunda and P o t e n t i l l a p a l u s t r i s . Bordering the areas of open water i s A r c t o p h i l a f u l v a . On the l e f t r a i s e d polygons are dominated by Betula glandulosa. (Photo by Lambert) Table No. 10 b Caricetum aquatilis caricosum aquatilis salicosum arbutifoliae Plot No. Plot size (m2) Date Analyzed PLOT DATA Locality Elevation ( f t ) PHYSIOGRAPHY Land form Relief: Profile Exposure (°) Slope gradient (°) CLIMATE Snow duration STRATA COVERAGE {%) C layer D layer PLOT COVERAGE {%) by water SOIL Drainage Hygrotope Depth of active layer (cm) CHEMICAL ANALYSIS No.of samples Organic layer No.of samples Organic -Mineral layer No.of samples Mineral layer 95 84 79 82 81 100 91 90 58 108 50 80 153 155 25 25 25 25 25 25 25 25 25 25 25 25 25 25 20/7 17/7 17/7 17/7 17/7 21/7 18/7 18/7 6/7 12/8 5/7 17/7 23/7 24/7 1965 1965 1965 1965 1965 1965 1965 1965 1965 1965 1965 1965 1966 1966 TL TL TL TL TL TL TL TL CL CL CL TL CL CL 490 490 510 510 510 570 620 620 1050 1050 1100 520 1050 1150 Drainage ... Old Old Lake Old . . Lake Old Drainage pathway creek edge creek edge lake pathway ...Flat.... Humm. ..Flat Stg. Flat Stg. Total.' 45 Total 180 0 Total 135 .0 1 0 1 2 0 2 Ik months. 50 75 80 85 95 55 50 35 95 90 70 15 35 30 20 35 60 20 90 15 50 35 40 20 20 15 40 30 30 35 2 1 1 OM 42.0 75-2 93.5 N% 1.01 1.47 2.24 C/N 24.3 29.7 24.2 P ppm 24 3 5 Na .68 .95 1.47 K .14 .47 .33 Ca 6.8 7.2 5-6 Mg 1-3 2.5 1.0 CEC 44.1 69.8 91.7 pH 4.0 4.5 4.5 OM U% C/N P ppm Na K Ca Mg CEC PH OM N% C/N P ppm Na K Ca Mg CEC PH .Impeded. ..Hydric. 30 89.0 1.83 28.4 3 .79 .26 16.0 2.0 87.5 4-4 37 48 35 34 40 38 87.6 1.05 48.4 33 2.23 1.11 9.7 3.0 63.4 3.8 1 43.7 .77 32.9 31 • 58 .59 6.1 1.8 46.8 4.6 1 56.5 1.4 23.4 3 .59 .13 14-9 6.6 49.3 4-4 1 1 1 12.7 30.4 33.9 .84 1.26 .59 8.8 14.0 38.2 12 5 24 .63 .87 .68 .09 .18 .29 9.0 8.4 4.1 1.1 2.6 .7 29.8 47.1 51.1 4.4 4-5 4.3 . m o n t h s . 60 98 100 80 80 80 35 ..Poor.. .Hydric. 21 30 1 1 1 1 1 2 3 84.2 46.7 84 2 92.5 81 7 87 2 1.47 .73 1 68 .92 1 46 1 47 33.2 37.1 29 1 58.3 35 1 31 6 6 21 5 5 17 18 1.19 .8 83 2.26 76 1 04 .61 • 42 63 .56 61 87 16.4 5.8 16 2 18.6 16 2 24 2 9.8 1.5 2 7 3.0 4 3 3 5 69.7 73.9 128 0 141.8 130 8 106 5 4-7 4.5 4 6 4.4 4 4 4 4 11.3 7.0 5.5 1.3 .17 .29 .18 .07 38.6 14-6 17.7 10.8 16 13 13 7 • 56 • .53 • 44 .71 .13 .26 .13 .3 3.3 7.3 5.1 6.1 .6 2.0 .6 1.0 23.6 34.6 55.3 32.4 4.6 5.7 4-7 4-4 Table No. | 0 a Caricetum a q u a t i l i s Number of Plots Plot No. Plot size (m ) Elevation ( f t ) C layer 1 Carex a q u a t i l i s 2 S a l i x a r b u t i f o l i a 3 P o t e n t i l l a p a l u s t r i s k Eriophorum angustifolium 5 Carex chordorrhiza 6 Eriophorum scheuchzeri 7 Carex r a r i f l o r a 8 Pedi c u l a r i s sudetica 9 Betula glandulosa 10 S a l i x pulchra 11 Andromeda p o l i f o l i a 12 Vaccinium uliginosum 13 Ranunculus p a l l a s i i 14. Calamagrostis canadensis 15 P e d i c u l a r i s lapponica 16 Ledum decumbens D layer (Bryophytes) 17 Sphagnum squarrosum 18 Polytrichum commune 19 Sphagnum recurvum 20 Sphagnum platyphyllum 21 Aulacomnium palustre 22 Aulacomnium turgidum 23 Sphagnum rube Hum 24 Sphagnum teres 25 Sphagnum contortum 26 Drepanocladus aduncus 27 Sphagnum lenense 28 Calliergon cordifolium 29 Mnium punctatum 30 Cinclidium subrotundum caricosum a q u a t i l i s 1 2 3 4 5 6 7 8 9 10 11 95 84 79 82 81 100 91 90 58 108 50 25 25 25 25 25 25 25 25 25 25 25 490 490 510 510 510 570 620 620 1050 1050 1100 7.1 7.2 8.3 3.1 7.2 5.1 6.1 5.1 7.1 8.3 8.2 1.1 - 1.1 1.1 4.1 4.1 3.1 - -4.2 - - 5.1 5.1 3.1 - - 3.1 3.1 - - - - 2.1 1.1 - - 6.1 6.2 2.1 - 6.1 - 7.1 - 4.1 - - - -- 1.1 1.1 1.1 5.1 •] 1 - - 1.1 - -- - - - 1.1 1.1 - 2.1 - - -1.1 - 4.2 5.2 6.2 - 8.4 - - 1.1 4.2 - - - - - - 1.1 1.1 1.1 - 3.2 4-2 2.1 4.2 - 1.1 2 .1 - 1.1 - - - 1.1 -- 5.2 - 5.2 -- 2.2 6.2 - - - - - - - -- 2.1 6.2 - 4.1 - 2.1 - 2.1 - 1.1 - 1.1 1.1 -salicosum a r b u t i f o l i a e TOTAL SPECIES (incl.sporadics) 6 10 13 11 11 Sporadic species C layer 31 Cardamine pratensis 50(1.1 32 Hippuris vulgaris 50(1.1 33 S a l i x glauca 50(1.1 34 Carex rotundata 82(4.1 35 Eriophorum vaginatum 155(1-1 36 Vaccinium v i t i s - i d a e a 153(1.1 D layer 37 Pogonatum alpinum 58(1.1) 38 Drepanocladus exannulatus81(1.1) 39 Lophozia excisa 83(+.+) 40 Lophozia kunzeana 83(+.+) 41 Sphagnum girgensohnii 83(7.3) 42 Sphagnum l i n d b e r g i i 84(6.2) 80 153 155 25 25 25 520 1050 1150 6.2 5.1 2.1 1.1 1.1 8.4 8.2 9.4 5.1 5.2 3.1 2.1 2.1 1.1 1.1 3.1 4.1 4.1 4.2 1.1 - 6.3 -1.1 3-2 3.2 6.3 8.4 7.3 2.1 1.1 3.1 3.2 4.2 4.2 3.2 5.2 14 15 15 43 Sphagnum obtusum 91(1.1) 44 Bryum pseudotriquetrum 95(1.1) 45 Mnium c i n c l i d i o i d e s 95(1-1) 46 Calliergon stramineum 153(1.1) 47 Calypogeia trichomanis 155(2.1) 48 Sphagnum balticum 155(4.2) Avg. Constancy Cover V 6.7 IV 2.3 III 2.0 II 1.2 II 1.2 II .6 II .6 II .3 II .5 II • 5 II • 4 I .3 I .2 I .1 I .1 I .1 III 2.1 III 1.0 II 1.5 II • 9 II .6 II -5 II .3 I .9 I .6 I .6 I .6 I -4 I .2 I .1 76 Sphagnum squarrosum. £. platyphyilum. S_. contortum, . S. l i n d b e r g i i and S. t e r e s c o n s t i t u t i n g the major cover i n the D l a y e r . A l l species can withstand sub-mergence and waterlogging over prolonged p e r i o d s . The caricosum a q u a t i l i s appears t o have a c l o s e r e l a t i o n s h i p t o the o l i g o t r o p h i a A l p i n e Carex - Sjphagnuni community i n Scotland described, by R a t c l i f f e (1964) and to the Sedge - Sphagnum - moss bog of northern Alaska described by Hanson (1953) and C h u r c h i l l (1955). (b) salicosum a r b u t i f o l i a e Three p l o t s were analyzed i n which Carex a q u a t i l i s and S a l i x a r b u t i f o l i a were present as co-dominants. Although the h a b i t a t s are extremely wet, hummocky co n d i t i o n s p r e v a i l throughout the p l o t s . Whereas these s i t e s might have been under water i n the past there i s no i n d i c a t i o n that there i s at present any movement of water over them. The kinds of s i t e s are a l l d i f f e r e n t and i n c l u d e a lake edge, o l d lake s i t e and an o l d drainage pathway. A f t e r the i n i t i a l l o s s of snow the Sphagnum hummock tops dry out r e l a t i v e l y r a p i d l y . No i c e wedges or patterned ground were observed i n these p l o t s , but the ground topog-raphy appeared t r a n s i t i o n a l between low-centered and.high-centered polygons. Snow dur a t i o n i s estimated to be 8 1/2 months w i t h no appreciable d i f f e r e n c e i n r a t e of thaw between hummock-depression m i c r o r e i i e f . There i s no open water present by mid-summer. Exposure i s t o t a l ; two p l o t s (83 and 155) were on very shallow slopes (2°). Species present on the hummocks i n c l u d e B e t u l a glandulosa Vaccinium uliginosum, Andromeda p o l i f o l i a , Ledum decumbens and P e d i c u l a r i s lapponica, while the wetter depressions are dominated by Carex a q u a t i l i s and S a l i x a r b u t i f o l i a . In p l o t s 153 and 155 Carex r a r i f l o r a i s present w i t h high coverage values i n the wet depressions. S a l i x p u l c h r a , with low coverage values, i s s c a t t e r e d throughout the p l o t s on the sides of the hummocks. Clumps of Sphagnum f i l l the wetter depressions, and i n c l u d e such species as S_. squarrosum and S. b a l t i c u m . An i n d i c a t i o n c f the semi-hydric c o n d i t i o n and p o s s i b l e 77 s u c c e s s i o n a l nature of the v a r i a t i o n i s the preponderance of Sphagnum recurvum that covers a large percentage of the hummocks. On the upper d r i e r pa.rts of the hummocks are s c a t t e r e d clumps of Sphagnum lenense, S. rubellum, S. g i r g e n s o h n i i , Aulacomnium tjcrrj^ idum and Polytrichum commune. Two analyzed.plots dominated by Carex a q u a t i l i s and Eriophorum a n g u s t i -f o l i u m appear r e l a t e d to the order C a r i c e t a l i a fuscae described i n Europe and reviewed by Brooke (1966). The major d i f f e r e n c e between the European and North American types i s the lack of Sphagnum species i n the l a t t e r type. In t h i s study, two p l o t s are considered as p a r t of the Caricetum a q u a t i l i s because of the presence of P o t e n t i l i a p a l u s t r i s . However, i t i s f e l t that they are a pos-s i b l e t r a n s i t i o n toward the Eriophoretum a n g u s t i f o l i i . 3. Eriophoretum s c h e u c h z e r i i Table 11 (a) $ (b) Low-centered polygons are considered to be i n d i c a t i v e of f l a t areas. They are u s u a l l y numerous i n p o o r l y drained areas p a r t i c u l a r l y i n wet sedge meadows. Th e i r d i s t r i b u t i o n and development i n the Mackenzie D e l t a region of western a r c t i c Canada has been described i n d e t a i l by Mackay (1963). Ice wedges that form i n poorly drained areas produce r i d g e s that enclose the f l a t ground be-tween them to give a saucer shape to the low-centered polygons. I n i t i a l l y , these s i t e s are covered by surface water throughout the growing season and sup-port marsh and aquatic v e g e t a t i o n . Tundra polygons are r a r e i n the Canoe Lake region except f o r one small area at the south end of the la k e . At Trout Lake they are more numerous. This can probably be r e l a t e d to the more r e g u l a r topag-raphy i n the l a t t e r r e g i o n . In both regions low-centered polygons are present only at lower e l e v a t i o n s i n areas of r e s t r i c t e d drainage where snow cover i s l i g h t and d u r a t i o n i s s i m i l a r to surrounding wet sedge meadow h a b i t a t s ( 8 1/2 months). Exposure i s always t o t a l because of t h e i r f l a t to concave p r o f i l e . The a c t i v e l a y e r i s narrow with the permafrost r e s t r i c t i n g any drainage. The waterlogged c o n d i t i o n of the s o i l r e s t r i c t s decomposition which accounts f o r the accumulation of peat. Table No. II b Eriophoretum scheuchzeri Plot No. Plot size (m ) Date Analyzed PLOT DATA Locality Elevation ( f t ) PHYSIOGRAPHY Land form Relief: P r o f i l e Expo sure ( 0) Slope gradient (°) CLIMATE Snow duration STRATA COVERAGE (%) C layer D layer SOIL Drainage Hygrotope Depth to active layer (cm) CHEMICAL ANALYSIS No.of sample s Organic layer 94 53 128 127 25 25 25 25 20/7 5/7 23/8 23/8 1965 1965 1965 1965 TL CL CL CL 500 1050 1130 1130 .Low-centered polygon. .Flat.. .Total. ...0... .85- months. 60 80 55 90 80 97 90 97 , Impeded. .Hydric. 20 4 26 0M 70.0 N% 1.61 C/N 25.9 P ppm 4 Na .91 K ' -28 Ca 8.7 Mg 1.8 92.7 1.8 32.7 .82 .32 6.5 1.0 CEC 62.4 160.6 109.8 160.3 pH 4-4 40 3 7 6 . 6 1.28 47.9 14 .78 .28 15.0 2.3 37 3 86.0 1.5 34.8 24 .64 .36 11.8 No.of samples Organic -Mineral layer 0M U% C/N P ppm Na K Ca Mg CEC pH 4 . 6 1 25.0 .13 112.0 3 . 4 6 • 05 2.8 . 6 6 7.3 4 - 9 4.2 1 17.4 .51 19.8 10 .62 .06 8.6 .8 47.3 4.1 4-3 1 23.9 • 5 27.7 10 • 53 .04 7.5 .4 67.8 4-7 Table No. 11 a Number of Plots Plot No. Plot size (m ) Elevation (ft) C layer 1 Eriophorum scheuchzeri 2 Carex rotundata 3 Betula glandulosa 4 Andromeda p o l i f o l i a Eriophoretum scheuchzeri 1 2 3 4 94 53 128 127 25 25 25 25 500 1050 1130 1130 Avg. Constancy Cover 7.3 6.3 8.3 9-4 V 7.5 4.1 2.1 2.1 2.1 V 2.5 3.1 - 7.2 - II 2.5 II 1.0 D layer (Bryophytes) 5 Sphagnum balticum 8.3 8.3 6 Polytrichum commune 1.1 1.1 7 Drepanocladus exannulatus 8 Aulacomnium turgidum 1.1 TOTAL SPECIES (INCL.SPORADICS) 11 11 Sporadic species C layer 9 Arenarla humifusa 53(+.+ 10 Cardamine pratensis 53(+.+ 11 Chrysosplenium tetrandrum 53(1.1 12 Equisetum arvense 53(1.1 13 Ranunculus gmelinii 53(1.1 14 Saxifraga cernua 53(1-1 15 Salix arbutifolia 94(2.1 16 Carex chordorrhiza 127(4-1 17 Ledum decumbens 128(2.1 18 Oxycoccus microcarpus 128(1.1 9-4 2.1 V 6.5 2.2 - IV 1.0 + .+ 9-4 II 2.5 2.2 - II .8 13 5 19 Pedicularis lapponica 128(2.1) 20 Rubus chamaemorus 128(2.1) 21 Vaccinium vitis-idaea 128(1.1) D layer (Bryophytes) 22 Drepanocladus aduncus 53(5-2) 23 Lophozia kunzeana 94(1.1) 24 Polytrichum juniperinum 94(3.1) 25 Scapania irrigua 94(+.+) 2.6 Sphagnum lindbergii 94(5.2) 27 Gymnocolea inflata l28(+.+) 78 The Eriophoretum s c h e u c h z e r i i i s considered to be under-represented w i t h only four p l o t s analyzed. Eriophorum scheuchzeri is. a l s o present along lake shores where i t u s u a l l y forms one of the c o n c e n t r i c bands a s s o c i a t e d with lake shore v e g e t a t i o n . However, the E_. scheuchzeri bands are u s u a l l y so narrow t h a t none were' analyzed. I n i t i a l development of the community i s i n open water. Two constant spe-c i e s E_. scheuchzeri and Carex rotundata c h a r a c t e r i z e the primary stage of de-velopment. A d d i t i o n a l s p e c i e s , present w i t h low coverage values, i n c l u d e Ranunculus g m e l i n i i , Cardamine p r a t e n s i s and S a x i f r a g a cernua. Cryophyte composition i s v a r i a b l e w i t h e i t h e r Drepanocladus exannulatus or Sphagnum bal t i c u m dominating. No two neighbouring low-centered polygons ever appear to have the same, dominant bryophyte. In l a t e r stages of development as the h a b i -t a t s become semi-hydric woody and herbaceous species with broad ranges of am-p l i t u d e become e s t a b l i s h e d . They i n c l u d e such species as Betula glandulosa, Andromeda p o l i f o l i a , Ledum decumbens, P e d i c u l a r i s lapponica, Rubus chamaemorus and Oxycoccus microcarpus. Two p l o t s r e p r e s e n t i n g t h i s stage were analyzed and i n both Sphagnum b a l t i c u m and S. l i n d b e r g i i were dominant i n the wetter areas. A s s o c i a t e d species on the l e s s s a t u r a t e d m i c r o h a b i t a t s i n c l u d e Polytrichum commune and Aulacomnium turgidum. 4. Caricetum r a r i f l o r a e Table 12 (a) £i (b) The i n i t i a l t r a n s i t i o n from low to high-centered polygons i s a r e s u l t of an increase i n s i z e and number of ice-wedges. As the ridges widen and are d i v i d e d again, peaty hummocks appear as unsorted features throughout what was o r i g i n a l l y a depression. Moisture c o n d i t i o n s w i t h i n these p l o t s are s t i l l h y d r i c to semi-hydric with the water t a b l e a t , c r near, the surface during the sum-mer montiis. Exposure i s t o t a l w i t h no p r o t e c t i v e slopes or low ridges surround-ing them. Snow cover and d u r a t i o n are estimated to be the same as f o r the Eriophoretum scheuchzeri. Drainage i n the hummocks and ridges i s improved because of t h e i r r a i s e d p o s i t i o n and they support a number of woody species.. Table No. 12 b Caricetum rariflorae Plot No. 80 156 151 Plot size (m ) 25 25 25 Date Analyzed 17/7 24/7 15/7 1965 1966 1966 PLOT DATA Locality TL CL CL Elevation (ft) 510 1100 1350 PHYSIOGRAPHY Land form Low-c entered polygon Relief: Profile Exposure (°) Slope gradient (°) CLIMATE Snow duration STRATA COVERAGE {%) C layer D layer PLOT COVERAGE {%) by water SOIL. Drainage Hygrotope Depth of active layer (cm) CHEMICAL ANALYSIS No.of samples Organic layer No.of samples Mineral layer ...Flat-Hummocky. Total 0 .8-g- months. 85 20 95 95 .Impeded. . .Hydric. 32 90 90 31 1 2 2 OM 92.5 92 5 88.8 N% .92 1 58 1.6 C/N 58.3 30. 8 30.8 P ppm 19 5 35 Na 2.26 93 1.27 K .56 73 1 .22 Ca 18.5 23 1 22.6 Mg 3.0 6 1 7.4 CEC U 1 . 8 102 5 108.7 ' PH 4.4 4 3 4.4 1 OM 2 8 N% 17 C/N 9 6 P ppm 12 Na 74 K 18 Ca 3 6 Mg 1 3 CEC 36 1 pH 4 0 Table No. 12 a Caricetum rariflorae 1 j Number of Plots 1 2 3 Plot No. 80 I56 151 Plot size (m2) 25 25 25 Elevation (ft) 510 1100 1350 Avg. C layer Constancy Cover 1 Carex rariflora 8.4 7.3 7.3 V 7.3 2 Carex rotundata 2.1 7.3 6.2 V 3.0 3 Salix arbutifolia + .+ 3.1 3-1 V 2.3 4 Betula glandulosa - 3-1 5-2 IV 2.7 5 Andromeda polifolia - 4-1 4-1 IV 2.7 6 Oxycoccus microcarpus - 3-1 4-1 IV 2.3 7 Ledum decumbens - 3.1 2.1 IV 1.7 8 Eriophorum scheuchzeri 2.1 - 2.1 rv . 1-3 9 Pedicularis lapponica - 1.1 2.1 IV 1.0 10 Vaccinium uliginosum - 2.1 + .+ IV 1.0 D layer (Bryophyte s) 11 Polytrichum commune 1.1 4.2 4-2 V 3.0 12 Sphagnum balticum - 7.3 6.3 IV 4.3 13 Sphagnum lenense - +.+ 7.3 IV 2.7 14 Aulacomnium turgidum - + .+ 3.1 IV 1.3 15 Sphagnum compactum - 1.1 1.1 IV .7 TOTAL SPECIES 10 16 21 (incl.sporadics) Sporadic species C layer 16 Carex aquatilis 80(1.1) 17 Pinguicula villosa 151(2.1) 18 Eriophorum angustifolium 15H+.+ ) 19 Pedicularis labradorica 151(+-+) 20 Rubus chamaemorus 151(1.1) D layer 21 Drepanocladus aduncus 80(1.1) 22 Sphagnum contortum 80(1.1) 23 Sphagnum obtusum 80(5.2) 24 Sphagnum platyphyllum 80(1.1) 25 Sphagnum imbricatum l5l(+.+) 26 Sphagnum rubellum 151(+-+) "27 Sphagnum aongstroemii 156(2.2) 28 Sphagnum recurvum 156(7.3) Depth to permafrost v a r i e s , being g r e a t e r under the peaty hummocks and ridges than the wet depression. Constant dominants i n the wetter areas are Carex r a r i f l o r a and C. rotundata. Also constant, but w i t h low coverage values, i s S a l i x a r b u t i f o l i a . Eriophorum  scheuchzeri i s present i n two p l o t s (83 and 151) w i t h low coverage. Woody spe-c i e s present on the hummocks are Betula glandulosa, Andomeda p o l i f o l i a , Ledum decumbens, Oxycoccus microcarpus and Vaccinium uliginosum plus s e v e r a l herba-ceous species i n c l u d i n g P e d i c u l a r i s lapponica and Rubus chamaemorus. Polytrichum commune i s the only constant bryophyte. Sphagnum ba l t i c u m and S. compactum between the hummocks and _S. recarvum, S.. lenense and Aulacomnium turgidum on hummock sides are present i n p l o t s 151 and 156. While i n p l o t 80 where there are fewer hummocks, _S. obtusum, S. p l a t y p h y l l u m and S. contorturn, a l l species able to withstand submergence, are the major bryophytes. B. Chionophilous p l a n t communities with snow dur a t i o n averaging ten months or more. Plan t communities i n the two study areas subjected to at l e a s t ten months snow cover do not d i s p l a y a great v a r i a t i o n . They may be d i v i d e d i n t o two major a s s o c i a t i o n s . The f i r s t , a very l a t e snow bed i n which p l a n t cover i s u s u a l l y l e s s than 50 percent and second, the l a t e snow bed or subalpine meadow i n which p r o s t r a t e w i l l o w , sedges and grasses predominate. There i s a t h i r d a s s o c i a t i o n which could be termed s l i g h t l y c h i o n o p h i l o u s , dominated by S a l i x shrubs, because of s e v e r a l chionophilous herbaceous species present i n the C l a y e r . While g e n e r a l l y found on the upper s i d e of l a t e snow beds where t h e i r height acts as a wind break, they are a l s o found below these beds where seepage i s p r e v a l e n t . A d d i t i o n a l l y , they occur along eroded drainage pathways where snow accumulates to great depths. No communities were found where snow.melt was so l a t e that phanerogams were completely absent. The lack of v a r i a t i o n i n these chionophilous p l a n t communities can probably be r e l a t e d to the q u a l i t y of the s o i l . Every s o i l p r o f i l e s t u d i e d i n these l a t e snow bed a s s o c i a t i o n s proved to be moderately a c i d . Conditions d i f f e r i n the chionophilous communities of the European Alps (Braun-Blanquet, 1932), T a t r a Mountains, Czechoslovakia ( K r a j i n a , 1933) and Sweden ( G j a e r e v o l l , 1950, 1956, 1965), where p a r a l l e l s e r i e s of plant.communities are found on calcareous and non-calcareous s o i l s . No d e t a i l e d i n f o r m a t i o n has been found to date i n the l i t e r a t u r e regarding chionophilous communities i n the subalpine region of a r c t i c Canada. Within the two study areas a t o t a l of three a s s o c i a t i o n s and nine v a r i a t i o n s are recognized and discussed below. 1. Salicetum pseudopolasis Table 13 (a) § (b) (Figure 22) S a l i x pseudopolaris a t t a i n s i t s g r e a t e s t abundance and dominates communi-t i e s i n the very l a t e snow bed s i t e s . T his community i s g e n e r a l l y present on moderately steep concave or s t r a i g h t slopes (15-28°) where snow melt i s very l a t e and i n some years never completed. Snow d u r a t i o n i s estimated to be be-tween 10 1/2 and 11 1/2 months. In 1965, one very l a t e snow bed s i t e i n an amphitheatre on the west cuesta at Canoe Lake (Figure 23) d i d not completely disappear. However, i n 1966 the snow bed had completely melted by mid-August. A l l sample p l o t s had southeast to south exposures. S o i l moisture con-d i t i o n s during the prolonged m e l t i n g p e r i o d are considered t o be h y d r i c or s e m i - t e r r e s t r i a l . A f t e r snow melt they e x h i b i t some dryi n g out, however, seep-age from above keeps them moist or h y g r i c r e g a r d l e s s of the length of time ex-posed. While p r e c i p i t a t i o n i n the area would g e n e r a l l y have l i t t l e a f f e c t on these s i t e s because of the very l a t e snow cover s o i l surface m a t e r i a l s are c o n s t a n t l y moving downslope due to snow creep and e r o s i o n by the many r i v u l e t s c r o s s i n g the exposed s o i l s u r f a c e . During snow melt the s o i l s are t e m p o r a r i l y waterlogged. Percent p l o t coverage by rock and exposed mineral s o i l i s c l o s e l y a l i g n e d to d u r a t i o n of snow cover. In p l o t 102 w i t h the longest snow cover, coverage was estimated at seventy percent. S a l i x pseudopolaris may form compact mats and i s a s s o c i a t e d w i t h other mat to f o l l o w page SO Figure 22. Salicetum pseudopolaris dominates the l i g h t brown areas bordering the upper edge and sides of the snow patch. Note the d u l l colour of the snow, a r e s u l t of the d e p o s i t i o n by wind of organic and i n o r g a n i c m a t e r i a l s . (Photo by K r a j i n a ) Figure 23. Amphitheatre (1400 f t . ) , Canoe Lake, bordered below by shrub (B ) S a l i x p u l c h r a and above by Lupino - Dryadetum * a l a s k e n s i s . (Photo by K r a j i n a e a r l y August 1965). Table No. 13 b Salicetum pseudopolaris P l o t No. 110 109 102 103 150 P l o t s i z e (m2) 16 16 16 16 16 Date Analyzed 13/8 13/8 10/8 10/8 15/7 1965 1965 1965 1965 1966 PLOT DATA L o c a l i t y CL CL CL CL CL E l e v a t i o n ( f t ) 1295 1300 U75 U 7 5 1480 PHYSIOGRAPHY Land form R e l i e f : P r o f i l e Expo sure ( 0) ..Creek.... bank ..Concave.. 135 135 Amphitheatre Creek bank . . . S t r a i g h t 180 180 Cvx-Stg 180 Slope gradient (°) 20 15 28 25 2 CLIMATE Snow du r a t i o n . . .11 months STRATA COVERAGE {%) C l a y e r 90 92 25 55 80 D l a y e r Moss 8 1 25 25 30 Lichen 3 5 3 10 Dr 10 3 PLOT COVERAGE (%) by rock 4 70 50 SOIL . Drainage Hygrotope .Moderate. . .Hjgric. .. Depth of a c t i v e l a y e r (cm) CHEMICAL ANALYSIS No.of samples Organic -Mi n e r a l l a y e r .Undetermined. No.of samples Mi n e r a l l a y e r 0M 27.8 25.3 N% .84 .67 C/N 19.2 21.9 P ppm 23 28 Na • 49 • 42 K .7 .63 Ca 13.2 8.7 Mg 4.1 2.3 CEC 41 -3 43.9 pH 5.8 • 4.8 4 4 4 4 2 0M 2.1 3-5 2.7 2.5 5.0 N% .15 .22 .2 .19 .31 C/N 8.2 8.7 8.3 6.2 9.4 P ppm 7 11 11 8 6 Na • 55 .73 .47 • 43 .72 K .17 .22 .23 .13 .28 Ca 7.5 10.0 3.8 3.2 13.1 Mg 1.8 3.1 .8 .6 1.3 CEC 13.1 17.6 17.4 28.6 29.0 PH 5-4 5-4 4-9 4-9 5.9 Table No. | 3 a Salicetum pseudopolaris (Lichenes) 37 Peltigera canina 38 Cladonia chlorophaea 39 Rhizocarpon geographicum 40 Peltigera spuria 41 Solorlna crocea 42 Lecidea granulosa 2.1 1.1 +.+ 1.1 1.1 1.1 2.1 1.1 1.1 1.1 1.1 + .+ 1.1 1.1 TOTAL SPECIES (incl.sporadics) 35 47 23 38 15 Number of Plots 1 2 3 4 5 Plot No. 110 109 102 103 150 Plot size (m^) 16 16 16 16 16 Elevation ( f t ) 1295 1300 1475 1475 1480 C layer Constancy 1 Salix pseudopolaris 8.2 2.1 3-2 6.3 6.3 V 2 Carex lachenalii 2.1 + .+ 5-2 2.1 6.2 V 3 Arenaria sajanensis 1.1 1.1 1.1 2.1 5.2 V 4 Oxyria digyna 3.1 2.1 2.1 - 5.1 IV 5 Sibbaldia procumbens 4.1 2.1 1.1 2.1 - IV 6 Artemisia t i l e s i i +.+ 1.1 - 6.3 1.1 IV 7 Dodecatheon frigidum 2.1 3.1 - 1.1 1.1 IV 8 Anemone na r c i s s i f l o r a + .+ 2.1 - 3.1 1.1 IV 9 Poa arctica 1.1 1.1 2.1 2.1 - IV 10 Ranunculus pygmaeus 4.1 - 5.2 - 7.3 II I 11 Arnica l e s s i n g i i - 4-2 1.1 4.2 - III 12 Artemisia arctica 1.1 5.2 2.2 - _ III 13 Ranunculus n i v a l i s 2.1 2.1 2.1 _ I I I 14 Saxifraga punctata 2.1 2.1 - . _ I I I 15 Polygonum bistorta 2.1 2.1 - + .+ _ III 16 Carex podocarpa - 6.2 - 3.1 II 17 Salix chamissonis + .+ 8.3 - _ - II 18 Equisetum arvense 3 .2 2.1 _ _ _ II 19 Myosotis alpestris 1.1 4.2 - - - II 20 Luzula confusa - - 2.1 3.1 _ II 21 Arctagrostis l a t i f o l i a 1 .1 3.1 - - - II 22 Trisetum spicatum - 2.1 - 2.1 - II 23 Saxifraga r i v u l a r i s 1.1 - 3.1 - - II 24 Epilobium anagallidifolium 3.1 + .+ - - - II 25 Petasites frigidus 1.+ 2.1 - - - II D layer (Bryophytes) 26 Polytrichum norvegicum _ 1.1 6.2 2.1 5.2 IV 27 Pohlia drummondii 4-1 2.1 3.1 5.2 - IV 28 Drepanocladus fluitans 1.1 - 1.1 1.1 1.1 IV 29 Polytrichum juniperinum 2.1 1.1 - 4-1 - I I I 30 Drepanocladus uncinatus 1.1 + .+ - 1.1 - III 31 Pogonatum alpinum 7.2 1.1 - - - II 32 Brachythecium albicans 3.1 3.1 - - - II 33 Bryum pseudotriquetrum - - - + .+ 1.1 II 34 Lophozia l a t i f o l i a - - + .+ - 1.1 II 35 Bryum sp. +.+ - +.+ - - II 36 Bartramia ithyphylla + .+ - - 1.1 - II I I I I I I II II II II Sporadic species C layer 43 Antennaria monocephala 4 4 Hierochloe alpina 45 Loiseleuria procumbens 46 Polygonum viviparum 47 Gentiana glauca 48 Taraxacum sp. 49 Senecio lugens 50 Aconitum delphinifolium 51 Festuca a l t a i c a 52 Arnica alpina 53 C a s t i l l e j a raupii 54 Pedicularis sudetica 55 Anemone richardsonii 56 Polemonium acutiflorum 57 S t e l l a r i a ciliatosepala 58 Achillea borealis 59 Salix reticulata 60 Saussurea angustifolia 61 Carex montanensis Avg Cove 5-0 3.2 2.0 2.4 1.8 1.8 1.4 1.4 1.2 3.2 1 .8 1.6 1.2 1.0 1.0 1.8 1 .8 1.0 1.0 1.0 2.8 2.8 .8 1-4 .6 1.6 1.2 • 4 • 4 • 4 • 4 103(4.3) 62 Lecidea flavocaerulescens 102(3.1 103(1.1) 63 Lecidea .iapicida 102(2.1 103(1.1) 64 Peltigera aphthosa 103(1-1 103(+.+ ) 65 Peltigera venosa 103(1.1 103(+.+ ) 66 Cetraria islandica 109(1-1 103(+.+ ) 67 Psoroma hypnorum 109(1.1 109(4-2) (Bryophyte s) 109(2.1) 68 Brachythecium s t a r k i i 103(1.1 109(2.1) 69 Scapania hyperborea 103(+ .+ 109(2.2) 70 Andreaea rupestris 103(2.2 109(2.2) 71 Bryum bimum 103(1 .+ 109(1-1)1 72 Dicranum mtthlenbeckii 109(2.1 109(1.1) 73 Mnium punctatum 109(1.1 109(1.1) 74 Rhacomitrium lanuginosum 110(2.1 109(1.1) 75 Distichium capillaceum 110(+.+ 109(1.1) 76 Scapania obliqua 110(+.+ 109(+.+ ) 77 Pohlia rutilans 150(5.2 109(+.+ ) 78 Lophozia alpestris 150(2.1 110(4-1) 79 Calliergon stramineum l50(+.+ 81 formers, sedges and v a s c u l a r p l a n t s . There are only three constant species i n the a s s o c i a t i o n : S a l i x p s e u d o p o l a r i s , Carex l a c h e n a l i i and A r e n a r i a s a j a n e n s i s . Three d i f f e r e n t i a l species c h a r a c t e r i s t i c of the Salicetum pseudo-p o l a r i s are d i s t i n g u i s h e d , they i n c l u d e A r e n a r i a s a j a n e n s i s , Epilobium a n a g a l l i d i f o l i u m and S a x i f r a g a r i v u l a r i s . Ranunculus pygmaeus, Oxyria digyna. and Sibbaldia. procumbens are a d d i t i o n a l important chionophilous species present i n the very l a t e snow bed community. In l a t e r stages of development (longer snow f r e e periods) such species as A r t e m i s i a t i l e s i i , Anemone n a r c i s s i f l o r a , Dodecathcon f r i g i d u m , A r n i c a l e s s i n g i i , Ranunculus n i v a l i s and S a x i f r a g a punctata are found w i t h very low coverage values. In the D l a y e r the most c h a r a c t e r i s t i c species present are Polytrichum  norvegicum, P o h l i a drummondii and Bartramia it.hyphylla_. Non-calcareous l a t e snow areas are the c h a r a c t e r i s t i c h a b i t a t f o r P_. ncrvegicum and P o h l i a drummondii ( G j a e r e v o l l , 1950). A d d i t i o n a l l a t e snow bed species are Drepanocladus f l u i t a n s , Bryum sp. and 15. a f f i n e . Several species with broad amplitudes of t o l e r a n c e are present i n the l a t e r stages of development, they are Polytrichum juniperinum, Drepanocladus uncinatus, Pogonatum alpinum and Brachythecium a l b i c a n s . Saxicolous l i c h e n s are very r a r e . However, two important l i c h e n s c h a r a c t e r i s t i c of these wet h a b i t a t s are present, they are Lecidea granulosa, and S o l o r i n a crocea. 2. Salicecetum chamissonis Table 14 (a) £ (b) Habitats dominated by S a l i x chamissonis i n the Canoe Lake area are very conspicuous both i n mid-summer by t h e i r snow cover and i n l a t e summer a f t e r snow melt by t h e i r dense l u x u r i a n t plant growth. Salicetum chamissonis i s poorly represented i n the Trout Lake area. A l l . s i t e s have a predominantly south to southeast exposure and are u s u a l l y on moderately steep creek bank slopes (be-tween 10-28°). The a s s o c i a t i o n occurs between. 1060-1800 f t e l e v a t i o n i n the subalpine zone at Canoe Lake and at 625 f t at Trout Lake. There appears to be 14 b Plot No. Plot size (ra2) Date Analyzed PLOT DATA Locality Elevation (ft) PHYSIOGRAPHY Land form Relief: Profile Exposure (°) Slope gradient (°) CLIMATE Snow duration STRATA COVERAGE {%) B2 layer C layer D layer Mosses Lichens SOIL Drainage Hygrotope Depth of active layer (cm) CHEMICAL AHALYSIS No.of samples Organic layer No.of samples Organic -Mineral layer No.of samples Mineral layer Salicetum chamissonis salicosura chamissonis 92 168 174 143 142 147 164 50 50 50 50 50 50 50 18/7 8/8 11/8 13/7 13/7 14/7 27/7 1965 1966 1966 1966 1966 1966 1966 equisetosum arvensis 170 50 CL 1550 CL 1600 CL 1800 .Creek bank.. .Straight.. Cvx-Hum Stg-Hum. Stg. Stg 135 90 90 135 135 135 3 20 25 15 14 10 Stg 90 10 months 100 100 65 90 5 148 50 14/7 1966 .Creek bank. ..Straight.. 90 120 20 10 .10^ - months. festucosum altaicae 162 50 26/7 1966 Cnv-Hum 120 15 10£ months 145 50 13/7 1966 CL 1500 Creek bank Cvx 120 15 Virctagrostidosum caricosum\ latifoliae montanensisX 157 50 25/7 1966 Lake edge Stg ' 3 5 5 100 70 5 .Moderate. ..Moist... .Moderate. ..Moist... Moderate • Moist.. .greater than 1.meter. Moderate .Moist.. over 50 cm Moderate -Moist.. C/N P ppm Mg CEC pH n C/N P ppm Ca Mg CEC pH 18.6 15.5 28.4 11.6 .65 .29 .65 • 38 16.6 31.0 25.3 17.7 20 19 19 8 1.07 1.06 1.18 .74 .63 1.04 1.03 .37 12.6 6.4 17.3 11.3 1.2 1.6 1.3 2.1 31.6 34.9 54.4 64.3 4.3 5.0 5.7 4 . 4 salicosum pulchrae 169 50 CL 1060 Bank slide Cnv 90 15 122 50 22/8 1965 140 50 12/7 1966 ..Concave... 90 90 17 15 80 5 20 98 100 100 100 100 100 100 100 100 75 100 98 40 35 28 30 90 45 60 30 50 65 60 35 2 2 1 20 5 5 t 2 .Moderate. ..Moist... 1 1 1 1 2 2 1 2 1 2 1 1 1 1 4 8 . 3 7 4 . 9 87.5 54.6 84.4 78.8 71.0 7 9 . 8 67.9 83.4 7 3 . 8 57 .3 87.3 71.4 1.26 1.59 1 .59 .53 1 .4 1.52 1.49 1.2 .95 1.35 1.3 1.34 1.61 1.08 2 2 . 2 27.3 27.6 59.7 3 4 . 9 30.1 27.6 3 9 . 2 4 1 . 5 3 5 . 8 3 2 . 9 24.8 3 1 . 4 38.3 30 15 23 23 40 15 19 33 16 31 19 16 31 33 .46 1 .06 1.22 .91 .94 1.14 • 99 1.09 .93 1.24 .89 1.58 .68 • 1 .2 1.09 . 5 7 1.04 1.43 .88 1.31 63 1.26 .79 1.68 .69 .78 1.63 1.48 20 .4 12.6 13.9 6 . 4 3 7 . 3 18.1 21.3 4 0 - 2 17.3 15.9 17.9 16.8 2 2 . 8 20.2 5 . 0 6 . 3 2 . 4 17.3 13.6 1.9 4 . 6 18.0 6.3 2.1 4 . 6 4 . 9 1 .9 . 9 36.4 9 7 . 4 109.0 64.3 128.7 101.5 87.0 112.8 67.7 119.3 108.8 68.3 146.0 105.5 5-2 5.8 4 . 2 4 . 5 6 .0 5.9 5.0 4 . 9 4 - 5 4 . 3 4 . 7 5 .7 4 . 8 5.1 2 3 3 1 4 1 1 3 2 4 1 2 4 3 3 OM 2 .2 .8 .9 .3 6.5 2.1 3.9 5-3 .9 1.3 4.8 4.8 2.7 5.3 3.9 u% .16 .04 .08 .03 .17 .1 .14 .14 .1 .09 .25 .17 .1 .14 • 15 C/N 8.5 10.1 4 . 8 5.8 20.8 12.7 16.2 17.4 6.4 7.6 9.4 15.2 12.5 1 9 . 6 15.1 P ppm 10 3 6 5 17 5 5 5 7 5 13 7 6 10 8 Na .41 • 75 .76 .84 .95 • 83 .81 .73 .68 .81 1.2 • 64 .85 .56 .98 K .1 .37 .38 .63 .82 .28 .71 .32 .24 .35 .87 • 49 .22 1.19 .52 Ca 4.8 1.8 3.0 6.1 4-4 29.4 9.0 6 . 4 29.0 5.3 17.6 6 .2 2.7 8.1 13.5 Mg 1.5 .38 .6 .6 6.1 5-2 .9 1.3 3.9 .78 • 3.8 1-5 1.8 .4 1.6 CEC 31.8 17.7 21.5 28.4 27.7 32.5 13.6 14.4 27.1 19.2 37.9 26.6 17.9 26.6 22.4 pH 4.8 5.5 5-3 5.3 4.7 5.5 5.7 6 .2 5.5 5.1 6.9 4-5 5.8 4 . 8 4.5 I 4 a Number of Plot: 2 r. 4 5 6 7 168 174 U3 142 147 164 50 50 50 50 50 50 625 1070 1250 1550 1600 1640 1800 equisetoaum arvenats festucosum altaicae carlcoBum montanensis arc ta gr0 stIdo aum latifoHae 1 2 170 148 50 50 1060 1640 162 50 1100 7 145 50 1500 - 157 50 1100 calicosum pulchrae 169 1 22 140 50 50 50 1060 1200 1400 1 Salix pulchra 2 Spiraea beauverdiana - 3 Equisetuffl arvenaa 2.1 7.2 5-1 5.1 6.1 8.2 8.2 8.3 8.2 - 5.1 1.1 7.2 5.1 4.1 V 5.2 4 Arctagrostis l a t l f o l l a 2.1 4.1 1.1 6.2 2.1 1.1 3-1 1.1 2.1 1.1 8.2 2.1 5-2 4.1 V 2.8 5 Aconitum dalphlnifoliujd 1.1 5-1 1.1 4-1 3.1 2.1 4-1 1.1 3-1 2.1 1.1 2.1 3.1 3-1 V 2.3 &-5aIlx chamissonis 7.2 6.2 7.2 6.2 7.3 7.2 8.3 - 2.1 - 2.1 - 5.2 8.4 7.3 rv 4.7 7 Carex montanensls - - 5.2 6.2 6.2 5-1 6.2 1.1 5.1 2.1 8.2 - - 3.1 4.2 IV 3-6 8 Artemisia arctica - - 7.2 + .+ 6.2 + .+ - 1.1 + .+ 6.2 4.1 7.2 2.1 3.1 6.2 rv 3-0 9 Petasites frigidus - 1.1 5.1 - 4.1 1.1 - 2.1 - 6.1 2.1 6.1 5.1 1.1 3.2 IV 2.6 10 Carex lanhenalil 2.1 4.2 2.1 2.1 2.1 3.1 4-2 3.1 2.1 4.2 1.1 4.1 2.1 IV 2.3 11 Dodecatheon frlgidun 3.1 - 3.1 6.2 3.1 4-1 3-1 - 2.1 - - + .+ - 2.1 6.2 IV 2.2 12 Ananona richardsonii 4.1 T.I 3.1 - 1.1 3.1 2.1 2.1 - - 5.1 1.1 3.1 IV 2.0 13 Saxifraga punctata - 2.1 3-1 1.1 3.1 2.1 3.1 2.1 4-1 1.1 - 2.1 - 4.1 rv 1.8 14 Poa arctica 2.1 1.1 3.1 1.1 3.1 4.2 1.1 1.1 2.1 2.1 1.1 2.1 IV 1.6 15 Trisetum spicatum + .+ 4.1 _ - 1.1 1.1 3.1 5-1 - 1.1 1.1 2.1 2.1 2.1 _ IV 1.6 16 Polemonium acutiflorum 1.1 3-1 2.1 - 2.1 + .+ 3-1 1.1 3.1 1.1 1.1 1.1 - 2.1 - IV 1.4 17 Ranunculus nivalis 2.1 3.1 - 3.1 1.1 1.1 - 2.1 1.1 1.1 1.1 - _ 2.1 IV 1.1 Salix pulchra - 1.1 1.1 - - 1.1 - - - - - - ? ? ? i n 1.3 18 Pedicularis sudetlca 3.1 2.1 3.1 2.1 2.1 2.1 1.1 i n 1.1 19 Polygonum Motorta - - 2.1 + .+ 2.1 1.1 - - - 2.1 3.1 - -f.+ - + .+ i n .9 20 Valeriana capitata 2.1 - - 1.1 - 1.1 3.1 - 1.1 - - 1.1 - - i n .5 Spiraea beauvardiana - - 6.2 - 1.1 - - - - 3.2 6.2 5.2 _ - ? 1  1.7 21 Artemisia t l l e s i i - 5-2 - - 2.1 - 4-1 7.2 - - - 1.1 3.2 _ - u 1.5 22 Fsetuca altalca - - 6.2 2.2 1.1 - - - 7.2 2.1 - - 1  1.3 23 Salix reticulata 5.2 2.1 6.2 7.2 2.1 1.5 24 Seneclo lugen3 - 2.1 - - - 1.1 4.1 2.1 1.1 - -. 2.1 - _ _ 1  .8 25 Myoaotis alpestrls - - - - 2.1 2.1 2.1 - 5.1 - - - - - - 1  .7 26 Epilobium anguatlfollun 3.1 4.1 2.1 2.1 - - 1  .7 27 Polygonum viviparura - 2.1 1.1 - - 1.1 2.1 - - - - - +.+ 3.1 - 1  .6 28 Vaccinium vitls-idaea 1.1 1.1 3.2 1.1 .4 29 Carex aquatilis 3-1 - - -t-.+ - - - - - - - - + .+ - 1  .4 30 Rumex arcticus 2.1 1.1 1.1 .3 31 Vaccinium uliginosum - - 1.1 - - - - - - 2.1 1.1 - + .+- - - 1  .3 32 Viola epipslla - - - 4-1 2.1 1 .6 33 Luzula wahlenbergil 5-2 4.2 - - - - - 1 .6 34 Anemone narcisslflora - - - 2.1 2.1 - - - - - - - - 4-1 1 .5 35 SteLlaria clliatosepala 36 Gentlana glauca 37 Pamaasia kotzebuoi 38 5tellarla longipes 39 Arnica alpina 40 Betula glandulosa 41 Rubus chamaemorus 42 Empetrum hermaphroditum 43 Arnica lesaLngli 44 Drepanocladus uncinatua 45 Bryum pseudotrlquetrum 46 Pogonatum alp In urn 47 Aulacomnium palustre 48 Polytrichia juniperinua 49 Clnclidium styglum 50 Brachythecium turgidum 51 Tomenthypnum nitens 52 Dicranum scoparlum 53 Pohlia nutans 54 Dicranum mtlhlenbeckii 55 Dicranum fusceecens 56 Lophosia quadrlloba 57 Scapania lingulata 58 Amblystegiua serpens 8.3 6.2 6.2 5-2 6.3 +.+ 5-2 5.2 1.1 6.2 4.2 5.2 4.2 4.2 6.2 1.1 5.2 59 Peltigera canina 1.1 .2 - 1.1 - _. 3.1 +.+ -60 Peltigera aphthosa 2.1 - 1.1 - _ 1.1 - - 2.1 - 2.1 61 Cetraria islandica 1.1 3.1 2.1 - _ 62 Peltigera scabrosa - - 1.1 - 2.1 1.1 - - 1.1 63 Peltigera spuria - - 1.1 - - - - 1.1 64 Cladonia gracilis 2.1 1.1 -TOTAL SPECIES 22 24 38 31 32 35 33 24 19 37 29 24 31 29 32 (incl.sporadics) Sporadic species C layer • layer (Bryophytes) 65 Potentilla fruticosa 92(3 1) 75 Ranunculus turneri 147(3 1) 85 BracbytheciuH albicans 122(6 2) 101 Mnium rugicum 66 Pedicularis capitata 92(2 D 76 Cardamine digitata 148(1 1) 86 Plagiothecium rooseanura 122(4 2) 102 Brachythecium sp. 67 Cardamine pratensla 122(1 1) 77 Anemone parviflora 164(2 1) 87 Polytrichum commune 122(3 1) 103 ttylocomium splendena 68 Carex lugens 122(1 1) 78 Cera3tium beeringianum 164(1 1) 88 Lophozia alpestrls 140(2 1) 104 Polytrichum norvegicum 69 Luzula conf una 122(3 1) 79 Chrysosplenium tatrandrum 164(1 1) 89 Drepanocladus flultans 140(1 D 105 Ptilidium ciliare 70 Oxyria digyna 142(2 1) 80 Eriophorum angustifolium 164(1 1) 90 Scapania lrrigua 143(2 2) 106 Pleuroiiun schreberi 71 Sibbaldia procumbens 143(3 1) 81 Ranunculus pedatifidus 164(2 1) 91 Scapania hyperborea 143(+ •0 107 Lcphoila kunzeana 72 Carex vaginata 145(2 1) 82 Saxifraga radlata 164(1 1) 92 Scapania lingulata 143(+ -0 73 Castilleja raupii 145(2 1) 83 Stellar la raonantha 169(2 1) 93 Lophozia l a t i f o l i a 162(5 2) (Llchenes) 74 Linnaea borealis 145(5 2) 84 Ranunculus pygmaaus 170(4 2) 94 Lophozia hatcheri 162(4 2) 108 Stereoeaulon alpinura 95 Barbilophozia barbata 162(1 1) 109 Cladonia squamosa 96 Lophozia porphyroleuca 162(1 1) 110 Lobaria l i n l t a 9? Cephalozia stollulifera' 162(+ + ) 111 Nephroma expallidum 93 Mnium hyraenophyllum 147(1 1) 112 Cladonia fimbriate 99 Amblystegium Juratzkanum 148(4 2) 113 Cetraria cucullata 100 Bryum sp. 170(8 3) 170(1.1) 170(».*) 174(2.1) 174(2.1) "4(2.1) 174(1.1) 174(1.1) 143(1.1) 162(1.1) 162(1.1) 162(3.1) 169(1.1) 174<*.-0 no v i s u a l evidence of downslope movement of surface m a t e r i a l s i n any of the sampled p l o t s , however, q u a n t i t a t i v e measurements would l i k e l y show that there i s downslope movement. During the annual summer thaw the s o i l i s waterlogged and s t i c k y f o r some time a f t e r the snow completely disappears, a f t e r which the s i t e always e x h i b i t s a c e r t a i n moistness but. no waterlogging. The l a t t e r i s due to the moderately steep slope of the h a b i t a t . The upper l i m i t s of the creek bank u s u a l l y support a shrub S a l i x pulchra community. I f t h i s i s absent, then a v e r t i c a l cut bank up to three f e e t high i s present. Snow accumulates with the f i r s t autumn snow f a l l , u s u a l l y before f r e e z i n g sets i n . Because the p r o t e c t i v e blanket of snow i s g e n e r a l l y present before f r e e z i n g sets i n each autumn, the a c t i v e l a y e r i s very t h i c k when com-pared with the m a j o r i t y of other h a b i t a t s i n the subalpine zone. No temperatures were taken at ground l e v e l below the snow cover, but i t i s assumed that readings would be s l i g h t l y above f r e e z i n g even i n mid-winter. During the w i n t e r wind blown snow i s packed i n t o the meadow s i t e s . In the f o l l o w i n g s p r i n g the snow bank, because of i t s compactness, i s very slow to thaw. Several f a c t o r s i n -fluence t h i s phenomena, they are r e l a t e d to the degree of s l o p e , exposure, amount of seepage from surrounding higher ground and the amount of d i r e c t sun-l i g h t r e c e i v e d by the snow bank. S i x v a r i a n t s are recognized i n the Salicetum chamissonis, four of them being represented by only one or two p l o t s . L i t t l e mention has been made i n e a r l i e r s t u d i e s undertaken i n northern Alaska concerning these snow bed/meadow h a b i t a t s so no comparisons are p o s s i b l e . In Scandinavia and Scotland ( R a t c l i f f e , 1964) herb and f e r n dominated communities have been described from the subalpine and a l p i n e areas of deep snow l i e . However, there appear to be no t r u e , f l o r i s t i c s i m i l a r i t i e s between the European and North American types. (a) salicosum chamissonis (Figure 24) The salicosum chamissonis i s the most common of a l l the l a t e snow bed communities i n the subalpine zone. Seven p l o t s were analyzed. Plant cover i s g e n e r a l l y dense and low because o f the p r o s t r a t e h a b i t s of S a l i x chamissonis, the dominant species. A s s o c i a t e d species with high constancy and coverage values are: A r c t a g r o s t i s l a t i f o l i a , Equisetum arvense, Carex l a c h e n a l i i , C. montanensis, Aconitum d e l p h i n i f o l i u m , S a x i f r a g a punctata, Polemonium a c u t i f l o r u m , Anemone r i c h a r d s o n i i , Dodccatheon f r i g i d u m , Ramoncuius n i v a l i s and Trisetum spicatum. The m a j o r i t y of the s o i l s arc r i c h i n a v a i l a b l e n u t r i e n t s (Ca and Mg) and t h i s i s r e f l e c t e d i n the presence and high coverage values i n c e r t a i n p l o t s of such species as S a l i x r e t i c u l a t a and Parnassis k o t z e b u i . A l l of the ass o c i a t e d species g e n e r a l l y have low s o c i a b i l i t y v a l u e s , tending to form sc a t -t e r e d clumps throughout the p l o t between the mats of S a l i x chamissonis. Figure 24. Salicetum chamissonis salicosum chamissonis. Close up of h a b i t a t . Shiny green leaves and aments are S a l i x chamissonis, 3-notched leaves - S i b b a l d i a procumbens and the f l o w e r i n g composite pl a n t on r i g h t i s A r n i c a l e s s i n g i i . (Photo by K r a j i n a ) Drepanocladus uncinatus, a species o f wide e c o l o g i c a l amplitude, domi-nates the moss f l o r a i n the meadow h a b i t a t s . In t h i s h a b i t a t i t i s a good i n d i c a t o r of moist c o n d i t i o n s . Other important bryophytes are: Bryum pseudotriquetrum, Pogonatum alpinum, Brachythecium turgidum and Aulacomnium p a l u s t r e . Lichens are never abundant i n any p l o t , only P e l t i g e r a species show-i n g any consistency of occurrence. Only one chionophilous community was analyzed i n the Trout Lake area ( p l o t 92). This community i s at the north end of the lake and at. one time was submerged. At the time of sampling, J u l y IS, 1965, there was no snow present. Snow duration i s o b v i o u s l y s h o r t e r here than at Canoe Lake and an i n d i c a t i o n of t h i s i s the presence of s c a t t e r e d B e t u l a glandulosa, S a l i x chamissonis, the major s p e c i e s , i s a s s o c i a t e d w i t h Anemone r i c h a r d s o n i i , S a l i x r e t i c u l a t a , Dodecatheon f r i g i d u m , P o t e n t i l l a f r u t i c o s e , Carex a q u a t i l i s , Ranunculus n i v a l i s , Polemonium a c u t i f l o r u m and Aconitum d e l p h i n i f o l i u m . The major mosses are Drepanocladus uncinatus and Aulacomnium p a l u s t r e . (b) equisetosum a r v e n s i s Two p l o t s (14S and 170) dominated by Equisetum arvense w i t h l i t t l e or no S a l i x chamissonis were analyzed. Snow d u r a t i o n i s estimated to be l e s s i n t h i s v a r i a t i o n than i n the salicosum chamissonis. This f a c t i s r e f l e c t e d i n the more abundant growth of the t a l l e r herbaceous species that combine to shade out the p r o s t r a t e S a l i x chamissonis. P l o t 170 i s at 1060 f t j u s t above the lake shore f l o o d zone. Seepage i s more prevalent here because of d i r e c t drainage from above. The s i t e a l s o gives evidence of past slumping. Equisetum arvens£ i s a common species on d i s t u r b e d s i t e s where seepage waters are c l o s e to the surface. A s s o c i a t e d species commonly found with Equisetum arvense i n c l u d e A r t e m i s i a t i l e s i i , A_. a r c t i c a , Myosotis a l p e s t r i s and Senecio lugens. Late snow bed spe-c i e s commonly a s s o c i a t e d w i t h the salicosum chamissonis are present and i n c l u d e Aconitum d e l p h i n i f o l i u m , Care.x montanensis, S a x i f r a g a punctata, Anemone r i c h a r d s o n i i , Polemonium a c u t i f l o r u m and Ranunculus n i v a l i s . Mosses are sparse w i t h only Drepanocladus uncinatus,.Bryum pseudotriquetrum, Pogonatum alpinum and Aulacomnium p a l u s t r e present. There are no l i c h e n s present i n e i t h e r p l o t . (c) festucosum a l t a i c a e The only s i t e ( p l o t 162} dominated by Festuca a l t a i c a was found i n the northeast: corner o f Div i d e d Lake at 1100 f t . There i s no higher ground above t h i s s i t e so that moisture c o n d i t i o n s are g e n e r a l l y d r i e r near the surface be-cause of a lack of seepage. Festuca a l t a i c a i s known to be c h a r a c t e r i s t i c of d r i e r more s h e l t e r e d slopes. The snow cover had disappeared from t h i s s i t e by mid-July. An i n d i c a t i o n of the longer snow f r e e p e r i o d i s the presence of Vaccinium uliginosum, V. v i t i s - i d a e a , Spiraea beauverdiana and Betula. glandulosa. While t h i s h a b i t a t i s probably d r i e r than those of the other v a r i a t i o n s , i t i s moister f o r a longer p e r i o d a f t e r the snow has disappeared. This assumption i s based on the high coverage of P e t a s i t e s f r i g i d u s and Luzula w a h l e n b e r g i i . Drepanocladus uncinatus, Pogonatum alpinum and Dicranum scoparium are present w i t h high coverage values. Lichen coverage i s estimated to be twenty percent. (d) caricosum montanensis As s o c i a t e d with subalpine and a l p i n e meadows and a common species i n the salicosum chamissonis, Carex montanensis i s present as a dominant i n only one p l o t (145). This h a b i t a t l i e s between a s p a r s e l y covered shrub S a l i x p u l c h r a p l o t and a salicosum chamissonis at 1500 f t . A c l e a r l y defined area approxi-mately 60 f t wide and 100 f t long i s distinguishable.. Snow melt i s completed s e v e r a l weeks before the lower salicosum chamissonis and the s i t e had d r i e d out appreciably by l a t e J u l y . The major species a s s o c i a t e d with Carex montanensis are not t y p i c a l l a t e snow bed species. Those present with high coverage values i n c l u d e Spiraea beauverdiana, A r t e m i s i a arctica., Polygonum b i s t o r t a , Epilobium a n g u s t i f o l i u m and Equisetum arvense. The t y p i c a l snow bed species such as Carex l a c h e n a l i i , Aconitum d e l p h i n i f o l i u m and Po1emonium a c u t i f1brum are s c a t t e r e d throughout the p l o t . Mosses and l i c h e n s are sparse with only Polytrichum juniperinum, 86 Dicranum muehlenbeckii and C e t r a r i a i s l a n d i c a haying r e l a t i v e l y high coverage values. (e) arctagrostidosum l a t i f o l i a e Only one p l o t (157), at 1100 f t on the north shore of Divided Lake and dominated by the u b i q u i t o u s A r c t a g r o s t i s l a t i f o l i a was analyzed. The h a b i t a t appears to be a more advanced l a t e snow bed as. i t i s estimated to be f r e e of snow s e v e r a l weeks before the salicosum chamissonis. The m a j o r i t y of the A r c t a g r o s t i s culms are estimated to be between 2-3 f t high i n l a t e J u l y . Seep-age occurs w e l l i n t o the summer, coming from the higher ground above the s i t e . Sub-dominant species w i t h high coverage values such as Carex l a c h e n a l i i , A r t e m i s i a a r c t i c a , P e t a s i t e s f r i g i d u s and Spiraea beauverdiana are present. Scattered throughout the p l o t are t y p i c a l chionophilous species such as Aconitum d e l p h i n i f o l i u m , Polemonium a c u t i f l o r u m , Dodecatheon f r i g i d u m and Trisetum spicatum. Drepanocladus uncinatus i s the dominant moss i n the p l o t , w h i l e l i c h e n s are absent. ( f ) salicosum pulchrae Included as a v a r i a t i o n i n the s y n t h e s i s t a b l e d e s c r i b i n g the Salicetum chamissonis are three p l o t s (122, 140 and 169) a l l c h a r a c t e r i z e d by a shrub l a y e r o f S a l i x p u l c h r a . Present, however, i n the C l a y e r are large mats of S a l i x chamissonis. As f a r as could be determined a l l three p l o t s give evidence of past downslope movement of surface m a t e r i a l s . P l o t 169 i s bordering a salicosum chamissonis w h i l e the" other two p l o t s are not. Snow du r a t i o n i n these h a b i t a t s i s estimated to be between 9 1/2 to 10 months each year. The sampled p l o t s range i n e l e v a t i o n from 1060-1400 f t and are excluded from a higher more exposed p o s i t i o n on the slopes by t h e i r t a l l growth. Aside from the presence of S a l i x p u l c h r a , species composition i n the C l a y e r i s s i m i l a r to that i n the salicosum chamissonis. This includes, v a s c u l a r p l a n t s , bryophytes and l i c h e n s . 3. Salicetum pulchrae Table 15 (a) § (b) This a s s o c i a t i o n i s considered to be only s l i g h t l y chionophilous because of the presence and high coverages of s e v e r a l shrub species. Habitats domi-nated by S a l i x p u l c h r a are c f l i m i t e d occurrence i n the subalpine zone. The most important c h a r a c t e r i s t i c s of the a s s o c i a t i o n are that the p l o t s are as-s o c i a t e d w i t h drainage pathways (between 1050-1825 f t ) or border l a t e snow bed communities where seepage i s prevalent throughout the summer. Shrub height i s f r e q u e n t l y reduced to l e s s than 3 f t at e l e v a t i o n s above 1500 f t . In the Canoe Lake region no large drainage pathways are present on west f a c i n g slopes. This can probably be r e l a t e d to the f a c t that the cuestas are so o r i e n t a t e d t h a t the scarp faces with t h e i r w e s t e r l y exposures do not. allow a s i m i l a r type of melt water run o f f and c o n t i n u a l seepage as experienced on the dip slopes. A d d i t i o n a l l y , the winds that are predominantly from the north-west allow l i t t l e accumulation of snow and, t h e r e f o r e , l e s s p r o t e c t i o n f o r t a l l shrubs. Three v a r i a t i o n s are recognized and described below f o r t h i s a s s o c i a t i o n , (a) salicosum pulchrae (Figure 25) The salicosum pulchrae i s d i s t i n g u i s h e d by the presence of t a l l (over 6 f t ) shrub S a l i x p u l c h r a . S i t e s are present only on the east f a c i n g slopes or along s h e l t e r e d creeks at lower e l e v a t i o n s (below 1500 f t ) . At the lower e l e v a t i o n s the thousands of small drainage pathways that cover the upper slopes converge to form r e c o g n i z a b l e creeks. The increased amount of run. o f f water cuts deeper i n t o the slope causing a thawing of the permafrost and r e s u l t i n g i n a widened channel. The beds of many of these drainage pathways are from 5-20 ft. below the l e v e l of the bordering tundra slopes. The communities that develop i n these p r o t e c t e d s i t e s are n a t u r a l l y s h i e l d e d from the abrasive and d e s i c c a t i n g w i n t e r winds. Snow accumulates e a r l y , as e a r l y as i n the meadow h a b i t a t s , and w i n t e r winds cause f u r t h e r b u i l d up during the winter by wind. In the s p r i n g and e a r l y Table No. | 5 b Salicetum pulchrae salicosum pulchrae betulosum glandulosae P l o t No. 105 126 111 165 175 U1 182 149 88 129 39 125 119 P l o t s i z e (m 2) Date 1 Analyzed 100 . . . 5 0 12/8 23/8 13/8 27/7 11/8 12/7 13/8 14/7 13/8 24 /a 2/7 23/S 21/8 1965 1965 1965 1966 1966 1966 i960 1966 1965 1965 1966 1965 1965 PLOT DATA L o c a l i t y CL CL CL CL CL CL CL CL TL CL CL CL CL E l e v a t i o n ( f t ) 1075 1150 1230 1260 1260 1375 1400 1500 630 1120 1160 1210 1825 PHYSIOGRAPHY Land form ....Old creek. Drainage way Exposed Drainag - way Lake Old ...Drainage way slope edge creek R e l i e f : P r o f i l e Cvx F l a t Gnv ...Cvx- {urn.. Cnv . . S t r a i g h t . . . . . F l a t Cvx Cnv Stg Exposure (°) 120 0 135 90 70 90 90 180 200 0 90 180 120 Slope gradient (°) 9 0 10 15 5 10 5 5 0 0 9 13 12 CLIMATE Snow duration STRATA COVERAGE (%) B1 l a y e r 80 30 80 85 70 90 80 85 B2 l a y e r 20 85 15 50 45 20 20 20 85 85 50 80 95 C l a y e r 95 90 90 70 80 90 90 85 15 70 60 90 80 D l a y e r Moss 75 85 85 90 95 40 90 50 100 90 65 70 95 Lichen 5 1 10 5 1 2 3 2 5 10 5 1 10 SOIL Drainage Hygrotope Depth of a c t i v e l a y e r (cm) .Semi-percolating. Hydric .Undetermined. 30 .Semi-percolating .Hydric to semi-hygric. 32 25 62 36 CHEMICAL ANALYSIS No.of samples Organic l a y e r 0M 63.1 49 5 64.6 88 3 84.7 33 0 91 5 54-5 57.2' 47.8 68.1 N% 1.68 1 68 1.96 1 .83 1.73 68 1 3 1.54 1.4 1.33 1.61 C/N 21.8 17 1 19-1 28 0 28.4 28 1 40 8 20.5 23.7 20.8 24.7 P ppm 42 16 21 12 31 20 29 13 40 10 41 Na • 94 67 .8 99 1.07 87 81 .9 1.05 .69 • 74 K 1.81 89 1.76 94 .89 72 94 1 .27 2.8 1.43 1.81 Ca 12.8 21 9 36.2 21 7 20.5 15 2 24 3 23.0 19.2 14.1 31.9 Mg 4.8 2 3 8.3 5 9 -3.4 9 12 0 10.3 6.5 3.8 5.1 CEC 121.0 53 8 96.0 100 8 127.5 22 7 > 87 4 103.0 141.0 83-4 88.1 pH 4.9 5 1 4-9 6 2 4.5 4 6 6 3 5.3 5.2 4-9 5.0 No.of samples 1 1 Organic - 0M 24 1 17 3 25-3 17.3 M i n e r a l l a y e r N* • 51 48 .76 .7 C/N 27 4 20 9 19.3 14-3 P ppm 12 27 6 4 Na 98 64 .44 • 54 K 91 97 .29 .14 Ca 11 1 26 1 9.6 7.6 Mg 4 5 6 3 4.4 1.6 CEC 38 5 63 5 48.3 29.3 PH 6 1 5 8 5.2 4.8 No.of samples 3 2 3 2 3 3 3 > 1 3 1 3 2 Mi n e r a l l a y e r OM 2.2 7 0 2.6 4 1 0.3 2 2 2.0 8 9 3.2 1.8 8.8 1.1 4.6 .4 31 .11 13 .05 08 • 09 29 .32 .27 .17 .14 .33 C/N 7.4 10 7 15.4 16 9 3.0 15 1 9.2 16 8 5.5 4.6 30.0 4.8 7.4 P ppm 9 3 11 5 4 12 4 15 13 13 11 5 15 Na .54 51 .58 82 .86 86 • 85 57 .65 .69 .87 .48 .52 K .12 15 .2 26 .21 34 .19 81 .31 .22 .21 .12 .19 Ca 3.5 12 6 6.9 3 2 3.5 9 1 2.7 18 6 8.8 7.2 3.7 3.0 7.9 Mg 1.1 1 2 1.8 1 3 .7 1 7 .6 4 4 1.4 1.7 1.2 .8 3.7 CEC PH 13.7 4.7 42 5 8 2 24.3 5.0 13 6 5 1 16.0 4.6 15. 4. 0 7 10.8 4.6 44 5 1 5 34.6 4.9 33.5 4.8 43.7 4.8 23-2 4.7 24.6 4-9 Table No. 1 5 O Number of Plots Plot No. Plot size (m2) Elevation (ft) Salicetum pulchrae salicosum pulchrae betulosum glandulosae 1 2 3 4 5 7 8 105 126 111 165 175 141 182 149 100 100 100 100 100 100 100 100 1075 1150 1230 1260 1260 1375 U00 1500 1 2 3 4 5 88 129 39 125 119 50 50 50 50 50 630 1120 1160 1210 1825 B layer 1 Salix pulchra Salix pulchra 2 Betula glandulosa 3 Vaccinium uliginosum 4 Spiraea beauverdiana 5 Alnus crispa C layer sub layer 6 Equisetum arvense 7 Petasites fr igidus 8 Arctagrostis l a t i f o l i a 9 Saxifraga punctata 10 Polemonium acutiflorum 11 Poa arctica 12 Anemone riehardsonii 13 Rubus chamaemorus Betula glandulosa Vaccinium uliginosum 14 Valeriana capitata 15 Pedicularis sudetica 16 Aconitum delphinifolium 17 Carex aquati l is 18 Dodecatheon frigidum 19 Linnaea borealis 20 Artemisia arctica 21 Eriophorum angustifolium 22 Artemisia t i l e s i i 23 Carex lugens 24 Vaccinium vit is-idaea 25 Ste l la r ia monantha 26 Pyrola secunda 27 Pyrola grandiflora 28 Carex lachenal i i 29 S te l la r ia ci l iatosepala • 30 S te l la r ia longipes 31 Empetrum hermaphroditum 32 Ranunculus lapponicus 33 Ledum decumbens 34 Ranunculus n iva l i s 35 Senecio lugens 36 Polygonum viviparum 37 Viola epipsi la 38 Saxifraga radiata 39 Carex montanensis 40 Myosotis a lpestr is 41 Epilobium angustifolium D layer (Bryophytes) ' 42 Drepanocladus uncinatus 43 Hylocomium splendens 44. Aulacomnium paluBtre 45 Sphagnum girgensohnii 46 Mnium rugicum 47 Bryum pseudotriquetrum 48 Pogonatum alpinum 49 Dicranum scoparium 50 Calliergon stramineura 51 Sphagnum squarrosum 52 Brachythecium turgidum 53 Plagiotheciura roeseanum 54 Bryum affine 55 Brachythecium sp. 56 Sphagnum rubellum 57 Calliergon cordifolium 58 Sphagnum teres 59 Tomenthypnum nitens 60 Sphagnum lenense 61 Sphagnum recurvum 62 Polytrichum juniperinum 63 Mnium cincl id io ides 64 Lophozia ventricosa 65 Lophoaia sp. 66 Ceratodon purpureus 67 Lophozia kunzeana 68 Pohlia nutans 69 Climacium dendroides (Lichenes) 70 Peltigera canina 71 Peltigera aphthosa 72 Cetraria pinastr i 73 Peltigera spuria 74 Peltigera scabrosa 75 Parmeliopsis ambigua 76 Lecidea sp. 9.4 ? 9.4 8.3 8.3 9.3 9-4 9-4 ? 9-4 V ? ? •> ? v 1.1 - - - - - - _ 3.1 - - - - 2.1 -4-2 - - 7.2 6.2 - 6.2 - - - - -2.1 1.1 1.1 2.1 2.1 2.1 7.3 5-2 3-1 2.1 7.3 6.2 6.2 + .+ 3.2 - - 8.3 4.2 -A.2 +.+ - 2.1 1.1 - - - - 2.1 - 7.2 2.1 - 3.2 4-1 - - 1 . 1 5-2 3.1 - 1.1 1.1 - 4.2 2.1 5-2 1.1 - - 6.2 2.1 - 1.1 - +.+ - - 1.1 - 1.1 1.1 - 8.3 -- 3-2 - - - 1.1 2.1 - 1.1 - 6.2 1.1 - 1.1 - 4.1 - 1.1 - 5-2 1.1 - 2.1 -- 1.1 2.1 - - 1.1 - +.+ - - - 3.1 - 1.1 3.1 -- +.+ - - - 1 .11 .1 + .+ - + . + -- + . + +.+ -1.1 _ _ _ _ _ _ 1.1 3.1 2.1 1.1 2.1 1.1 1.1 2.1 1.1 TOTAL SPECIES (incl._poradi.es) 36 30 36 24 30 29 24-Sporadic species C layer 77 Pedicularis lanata 78 Pedicularis capitata 79 Pedicularis lapponica 80 Potenti l la nalustris 81 Lycopodium annotinum 82 Calamagrostis canadensis 83 Ranunculus pygmaeus 84 Pedicularis arct ica 85 Polygonum bistorta 86 Arnica less ing i i 87 Polygonum alaskanura 88 Rosa acicular is 89 Anemone parvif lora 2.1 2.1 4 8.3 7.2 9-4 9-4 - 2.1 2.1 1.1 2.2 - 2.1 1.1 4.1 3.1 3-2 +.+ 6.2 2.1 5-2 8.3 - - 7.3 7.3 5-2 5-2 - 6.2 - 6-3 5-3 5.2 -- 4.2 + .+ - 2.1 1.1 1.1 1.1 4-2 1.1 1.1 - 2.2 - 4.. .1 + .-t - 1.1 4.2 -- 4.2 -.1 1.1 1.1 4.2 2.1 2.2 3.2 27 34 33 21 Constancy II II II III III III III III III Avg. Cover 8.3 7.2 7.3 5.2 - 7.2 5.2 9.2 2.1 5.2 1.1 ' 6.2 _ V 4.7 8.3 6.1 6.2 5.2 5.2 7.2 6.2 5.2 - 4.1 _ 5.2 1.1 V 4.4 4.1 4.1 3.1 - 4.1 - 6.2 - - 4.1 1 . I 2.1 IV 2.1 - 2.1 4.1 2.1 1.1 2.1 4.1 2.1 - 1.1 _ _ 1.1 IV 1.4 1.1 3.1 4.1 3.1 1.1 1.1 3-1 2. 1 IV 1.4 3.1 - 2.1 2.1 2.1 - 2.1 - 2.1 - 2.1 - IV 1.2 - 5.2 2.1 2.1 - 5-1 6.2 2.1 - 3.1 - - - III 1.9 3.1 1.1 - - - 4.1 - - - 4.1 4.1 3.1 3.1 III 1.7 9 ? 4.2 3.1 3.1 ? III 1.6 ? - - - 3.1 - - - 1.1 ? 1.1 - 1.1 III 1.4 - 2.1 1.1 4.1 - 2.1 - 4.1 - 1.1 - - - III 1 .0 2.1 - - - 1.1 - - 2.1 - 2.1 2.1 2.1 2.1 III 1 .0 1.1 - 3.1 - - 3.1 2.1 - 1.1 2. 1 - - III 1 .0 4.1 1.1 3.1 - 5-2 2.2 - II 1.0 - 3.1 - 4.1 - 1.1 - 4.1 2.1 - - - II 1 .0 3.2 - - - 6.3 1. 1 - - - 2.2 2.1 - - II 1.0 - 1.1 + .+ - 6.2 - - - 2. I - - - II .8 - - 4.2 3.1 3.2 II .8 - 2.1 2.1 - - 3.1 2.1 - II .7 1.1 - - 1.1 - 7.3 II .7 2.1 - - - 2.1 - - - - - 2.1 1.1 II .7 3.1 3.1 + .+ 1.1 - - - - II .7 • 4 • 3 • 3 • 3 • 3 .3 .5 .4 • 4 • 3 .2 .2 .2 4.0 2.7 2.3 1.4 1.2 1.2 1.0 .7 •5 • 5 . 1 39(+.+) 90 Cardaraine digitate 165(+ +) 101 Scapania irr igua H1(+.+ ) 114 Pleuroziuro schreberi 165(+ 88(1.1) 91 Delphinium glauca 165(+ + ) 102 Cinclidium arcticum 125(+.+) 115 Dicranum fuscescens 182(2 88(+.+) 92 Ranunculus pedatifidus 165(1 1) 103 Blepharostoma trichophyllum 126(+.+ ) 116 Lophoaia excisa 182(1 88(1.1) 105(1.1) 93 Salix riehardsonii 165(7 3) 104 Lophozia obtusa 126(+.+) 117 Plagiothecium curvifolium 182(1 94 Lycopodium selago 175(3 2) 105 Marchantia polymorpha 126(+.+) (Lichenes) 111(1.1) 106 Nardia scalaris 126(+.+ ) 118 Cetraria n iva l is 39(1 111(+.+) D layer (Bryophytes) 107 Aulacomnium turgidum 141(2.2) 119 Peltigera polydactyla 39(1 119(1.1) 95 Sphagnum inundatum 39(+ + ) 108 Cinclidium stygium U1(2.1) 120 Cetraria sepincola 88(1 119(2.1) 96 Lophozia bicuspidata 88(1 1) 109 Dicranum elongatum 141(1.1) 121 Peltigera malacea 88(+ 125(1.1) 97 Dicranum muhlenbeckii 105(2 1) 110 Mnium punctatum 141(2.1) 122 Nephroma expallidum 105(1 129(1.1) 98 Encalypta rhaptocarpa 105(+ + ) 111 Drepanocladus aduncus 149(2.1) 123 Psoroma hypnorum 105(1 129(2.1) 99 Polytrichum commune 105(1 1) 112 Mnium hymenophyllum 165(+.+ ) 165(2.1) 100 Brachythecium albicans 111(1 1) 113 Mnium rostratum 165(2.1) summer one may walk across these creeks wi thout r e a l i z i n g tha t there are S a l i x shrubs over 8 f t h i g h under the snow. F igu re 25. S a l i c e t u m pu lchrae s a l i c e t o s u m p u l c h r a e . d r a i n -age pathway b o r d e r i n g lake edge, Canoe Lake. Equisetum arvense and P e t a s i t e s f r i g i d u s dominate the C l a y e r (Photo by K r a j i n a ) The pro longed snow cover i n the sa l i cosum pu lchrae can, i n p a r t , be a t -t r i b u t e d to the dense canopy which acts as an i n s u l a t i o n thereby r e t a r d i n g ground snow me l t . F l o w e r i n g and l e a f i n g out by the shrubs g e n e r a l l y occurs i n l a t e May and e a r l y June. The ground sur face topography i s very i r r e g u l a r , c o n s i s t i n g o f d ips and r i dges that are a r e s u l t o f r a p i d downslope movement o f melt water tha t occurs under the snow dur ing the thaw and a f t e r snow has d i s a p -peared. The spec ies groupings and s o i l p r o f i l e s vary w i t h i n each h a b i t a t and can be r e l a t e d to the meandering sur face water tha t depos i t s both o rgan ic and i n o r g a n i c m a t e r i a l s throughout the s i t e du r ing the annual thaw. Shrub 89 composition, however, remains constant and i s l i t t l e a f f e c t e d by f l o o d i n g . P e r e n n i a l l y frozen ground was never reached i n any s o i l p i t (the deep-est was 53 cm). This depth, however, i s no i n d i c a t i o n that permafrost i s e i t h e r absent or present. K r a j i n a (personal communication) s t a t e d that fx-ozen ground was recorded c l o s e to the surface (20 cm) i n one s i t e on the bank at Canoe Lake i n 1963. However, i t i s f e l t t h a t t h i s could be p a r t of the unthawed a c t i v e l a y e r or b u r i e d i c e as the v e g e t a t i o n was sampled i n J u l y . Root p e n e t r a t i o n i s deep i n r e l a t i o n to the m a j o r i t y of other a s s o c i a t i o n s -up to 46 cm. The S a l i x p u l c h r a roots are predominantly i n the upper 30 cm where they form an extensive network. The water t a b l e i s normally high i n these h a b i t a t s , although seepage l e v e l s depend on degree of slope and extent of area of upper slope being drained by the creek that supports the shrub S a l i x pulchra. Seepage water i s always present w i t h i n 15-20 cm of the surface even i n l a t e August and created a problem i n d e s c r i b i n g and c o l l e c t i n g s o i l p r o f i l e data. S c a t t e r e d low shrubs (between 1/2-2 f t high) a s s o c i a t e d w i t h S a l i x p u l c h r a are: B e t u l a glandulosa, Vaccinium uliginosum and Spiraea beauverdiana. The C l a y e r species composition i s g e n e r a l l y s i m i l a r to the l a t e snow bed communi-t i e s w i t h Equisetum arvense and P e t a s i t e s f r i g i d u s having the highest constancy and coverage values. S a l i x chamissonis was absent from a l l sampled p l o t s . T y p i c a l chionophilous species that are present i n the shrub a s s o c i a t i o n i n c l u d e Polemonium a c u t i f l o r u m , Anemone r i c h a r d s o n i i , Aconiturn d e l p h i n i f o l i u m , Dodecatheon f r i g i d u m , Carex l a c h e n a l i i and C. montanensis. These species are of r a t h e r s c a t t e r e d occurrence u s u a l l y being present on the higher areas border-i n g the f l o o d zone. D i f f e r e n t i a l species i n the salicosum pulchrae are: Polemonium a c u t i f lorum, A r t e m i s i a t i l e s i i , S t e l l a r i a monantha, S_. c i l i a t o s e p a l a , Carex l a c h e n a l i i , Ranunculus n i v a l i s and Seneclo lugens. The bryophyte f l o r a i s dominated by Drepanocladus uncinatus and Bryum pseudotriquetrum. These, and other minor s p e c i e s , g e n e r a l l y form cushions i n s h e l t e r e d p o s i t i o n s or on the bases of the S a l i x p u l c h r a . C o r t i c o l o u s mosses are present i n the m a j o r i t y of p l o t s . P e l t i g e r a species are the major ground l i c h e n s present, a l l w i t h very low coverage values, (b) betulosum glandulosae Dwarf shrub communities ( l e s s than 3 f t high) dominated by S a l i x p u l c h r a are r a r e i n the two study, areas. They are never a s s o c i a t e d with l a t e snow bed communities. This i s borne out by the absence of chionophilous v a s c u l a r spe-c i e s u s u a l l y found under such c o n d i t i o n s . The sampled p l o t s are r e s t r i c t e d to both upland and lowland drainage pathways except i n one case ( p l o t 88) an ex-posed lake. edge. At Canoe Lake the p l o t s are present at. e l e v a t i o n s between 1120-1825 f t and at 630 f t at Trout Lake. Slope gradients vary from 0-13° with exposures g e n e r a l l y to the southeast. The s i t e s are c o n s t a n t l y wet because of f r e e water f l o w i n g downslope during the e n t i r e summer. The s m a l l e r o v e r a l l height of the shrub S a l i x p u l c h r a does not n e c e s s a r i l y mean that the s i t e s are younger than the salicosum pulchrae. The sampled p l o t s and surrounding areas are almost e q u a l l y exposed to winds from any d i r e c t i o n . The m i c r o r e i i e f i n the betulosum glandulosae i s s i m i l a r to that i n the salicosum pulchrae. Moss mounds are present, or i n the process, of forming. T h e i r growth and development i s f u r t h e r r e l a t e d to the movement of the drainage water i n the s i t e . The betulosum glandulosae i s probably an intermediate stage r e l a t e d to mass movement of slope m a t e r i a l s that r e s u l t i n a c h a n n e l l i n g of drainage water Over a p a r t i c u l a r s i t e . This f r e e f l o w i n g water i s i n s u f f i c i e n t to erode the s u b s t r a t e and produce a h a b i t a t able to support t a l l shrubs. Fur-t h e r mass movements cause a change i n d i r e c t i o n of flow and the pathways dry out. Bordering communities encroach and, i n . t i m e , replace the lew shrub. This i s n a t u r a l l y a very slow process. Duration of snow cover i s estimated to be between 9-9 1/2 months, depend-ing on exposure and e l e v a t i o n . The low shrub cover i s net e f f e c t i v e i n 91 r e t a i n i n g snow during the w i n t e r and the canopy does not g r e a t l y reduce the amount of i n s o l a t i o n reaching the ground l e v e l . Permafrost was recorded i n every sampled p l o t , although great v a r i a t i o n s i n depth was found (20-62 cm). The t r a n s i t i o n a l p o s i t i o n of t h i s v a r i a t i o n i s i n d i c a t e d by the presence of only two constants - B e t u l a glandulosa and S a l i x p u l c h r a . Many broad ranging s p e c i e s are present, not one i n more than s e v e n t y - f i v e percent of the p l o t s , such as A r c t a g r o s t i s l a t i f o l i a , S a x i f r a g a punctata, ¥accinium v i t i s - i d a e a , V. uliginosum, Ledum decumbens, Spiraea beauverdiana, Eqiuisetum arvense and Petasit.es f r i g i d u s . Vascular p l a n t s g e n e r a l l y a s s o c i a t e d w i t h p o o r l y drained and/or seepage h a b i t a t s are a l s o present: Alnus c r i s p a , Rubus chamaemorus, V a l e r i a n a c a p i t a t a , P e d i c u l a r i s s u d e t i c a , Carex a q u a t i l i s , Eriophorum a n g u s t i f o l i u m and P y r o l a g r a n d i f l o r a . In the D l a y e r the ground l i c h e n s are mainly P e l t i g e r a s p e c i e s , w h i l e C e t r a r i a p i n a s t r i , a c o r t i c o l o u s s p e c i e s , i s present on the S a l i x p u l c h r a shrubs. The downslope movement of f r e e f l o w i n g melt water r e s t r i c t s the establishment of Sphagnum species to r a i s e d areas. These areas arte covered by combinations of Sphagnum g i r g e n s o h n i i , S_. rube Hum and S_. lenense. Small wet pockets with l i m i t e d water movement support Sphagnum squarrosum amd S_. t e r e s . The major bryophytes that occur i n the f l o o d zone are: Drepanocladus uncinatus, Aulacomnium p a l u s t r e and Mnium rugicum. Around the - foases of the shrubs and i n s i t e s above the f l o o d zone Hylocomium splendens i s afeundant. (c) salicosum r i c h a r d s o n i i Two p l o t s dominated by shrub s i z e (under 6 f t ) S r a i i x r i c h a r d s o n i i were analyzed at Canoe Lake. Both s i t e s have w e s t e r l y exposures the gradient i n p l o t 177 i s 50°, while i n p l o t 124 only 1°. Snow d i i u B s t i o n i s estimated to be 9 months. P l o t 177 could p o s s i b l y be considered as. s l i g h t l y chionophilous because of the high coverage of Cassiope tetragona.. M o i s t u r e c o n d i t i o n s are considered to be h y g r i c w i t h seepage continuous throughout the summer. Both 92 p l o t s are probably t r a n s i t i o n a l as they have high i n d i c e s of s i m i l a r i t y w i t h p l o t s from d i f f e r e n t a s s o c i a t i o n s . S a l i x r i e h a r d s o n i i has not been recognized by any of the e a r l i e r workers i n western a r c t i c North America as a dominant shrub due to i t s r a t h e r s c a t t e r e d occurrence. S. r i e h a r d s o n i i i s not abundant at Canoe L a k e ( i t i s absent at Trout Lake), and where present i s a s s o c i a t e d w i t h d i s t u r b e d s i t e s where seepage i s p r e v a l e n t . The highest q u a n t i t y of a v a i l a b l e calcium i n the upper ho r i z o n of any s o i l p r o f i l e was recorded i n p l o t 124 (75 meq/100 gm). Major species a s s o c i a -ted w i t h S a l i x r i c h a r d s o n i i n the two sample p l o t s are: Vaccinum uliginosum, V. v i t i s - i d a e a , Sali_x r e t i c u l a t a , Dry as o c t o p e t a l a , A r c t a g r o s t i s l a t i f o l i a , Emp e t. rum h e rm a ph r o d i t urn, P e t a s i t e s f r i g i d u s , Ledum decumbens, Arctostaphylos  a l p i n a and T^uisetum scirpo.id.es. In both p l o t s the D l a y e r coverage i s over n i n e t y - f i v e percent, with mosses predominant. Species with high coverage values i n c l u d e Tomenthypnum n i t e n s , Hylocomium splendens, Aulacomnium turgidum, A. p a l u s t r e , Sphagnum rubeHum, Dicranum angustum and P t i l i d i u m c i l i a r e . Lichen coverage i s not h i g h , only t h i r t y percent i n p l o t 177 and only ten per-cent i n p l o t 124. The only constant species are C e t r a r i a c u c u l l a t a , Cladonia amaurocraea and C. m i t i s . 93 SOILS To a s s i s t i n p r o v i d i n g a b a s i c set of informat i o n on subalpine a r c t i c s o i l s as w e l l as to determine the edaphic environment of subalpine p l a n t s and pl a n t communities s o i l samples were c o l l e c t e d f o r a n a l y s i s from a s o i l pit. dug w i t h i n each community analyzed. From each p i t in f o r m a t i o n was c o l l e c t e d on thickness and depth of ho r i z o n s , depth of a c t i v e l a y e r or l a t e r i n the season to permafrost, c o l o u r , moisture, stoniness and s t r u c t u r e . The presence and depth of r o o t i n g w i t h i n each horizon v/as al s o determined. Chemical analysis"'' of the s o i l s i n c l u d e d pH, organic matter content, t o t a l n i t r o g e n , adsorbed phosphorus, c a t i o n exchange c a p a c i t y and exchangeable calcium, magnesium, potassium and sodium. Carbon/Nitrogen (C/N) r a t i o s were calculated, from these data. A d d i t i o n a l l y , the t e x t u r e of each s o i l sample was s u b j e c t i v e l y de-termined by hand i n the l a b o r a t o r y . Pebble s i z e d rocks present i n the horizons were c o l l e c t e d and determined. Methods of S o i l Sampling, D e s c r i p t i o n and A n a l y s i s The l o c a t i o n of the s o i l p i t was determined i n r e l a t i o n to the ve g e t a t i o n and topographic f e a t u r e s of the community. P i t s were dug to e i t h e r permafrost (the a c t i v e l a y e r i n the e a r l y part of the season), water t a b l e , coarse i c e shat t e r e d parent m a t e r i a l or bedrock. G e n e r a l l y permafrost can be s a i d to be the l i m i t of root p e n e t r a t i o n but where the a c t i v e l a y e r had not thawed no p o s i t i v e determination of depth of r o o t i n g could be made. S o i l samples f o r l a b o r a t o r y a n a l y s i s were c o l l e c t e d from a l l recognizable h o r i z o n s . While some horizons were extremely t h i n or dis c o n t i n u o u s , they were taken where p o s s i b l e as they g e n e r a l l y tended to be organic, i n c l u s i o n s w i t h i n coarse m a t e r i a l . Samples of the l i t t e r and fermentation (L and F) horizons were not always c o l l e c t e d due to the s c a r c i t y and d i s t r i b u t i o n of such m a t e r i a l . Samples were a i r - d r i e d i n the Inuvik Research Laboratory, sieved w i t h a U.S. 1. A l l chemical analyses with the exception of pH were c a r r i e d out by Mr. B. von S p i n d l e r , Department of S o i l Science, U n i v e r s i t y of B r i t i s h Columbia. 94 s e r i e s No. 10 (2.00mm) siev e and stored i n p l a s t i c bags. A t o t a l o£ 498 s o i l samples were c o l l e c t e d and chemi c a l l y analyzed from the 166 p l o t s s t u d i e d . These s o i l samples and. p r o f i l e d e s c r i p t i o n s represent d i f f e r e n t as w e l l as s i m i l a r p l a n t communities w i t h i n two b a s i c a l l y s i m i l a r g e o l o g i c a l areas. The topographic p o s i t i o n s and exposures were v a r i a b l e as were the e l e v a t i o n s of many of the s i m i l a r plant, communities. S o i l pH was determined electromet.rica.il/, u t i l i z i n g a Beckman Model N pH meter, on samples mixed to a paste consistency. Percent organic matter was determined using the Walkerly-Black wet combustion (K^CrnG^ o x i d a t i o n ) method as adapted by the Department of S o i l Science, U n i v e r s i t y of B r i t i s h Columbia. For t o t a l n i t r o g e n a macro-Kjeldal method f o r s o i l (NH d i s t i l l e d i n b o r i c a c i d , t i t r a t e d w i t h s u l p h u r i c acid) was used. C/N r a t i o s were c a l c u l a t e d from these data on the accepted assumption that organic matter contains 58 percent carbon (Jackson, 1958) . Adsorbed or a v a i l a b l e phosphorus (Metson, 1961) was determined c o l o u r i m e t r i c a l l y using the d i l u t e a c i d - f l u o r i d e e x t r a c t i o n method (method 1) of Bray and Kurtz (1945) as adapted by the Department of S o i l Science, U n i v e r s i t y of B r i t i s h Columbia. Exchangeable ca t i o n s (Ca,Na,K and Mg) were e x t r a c t e d from the s o i l with IN ammonium acetate (pH7) and concentrations of the four cations were, determined on a Perkin-Elmer flame photometer as adapted by the Department of S o i l Science, U.B.C. Cation exchange c a p a c i t y ('CEC) was determined using the leached s o i l a f t e r washing with e t h y l a l c o h o l , and then d i s t i l l a t i o n of ammonia i n t o b o r i c a c i d and t i t r a t i o n w i t h d i l u t e s u l p h u r i c a c i d . Percent base s a t u r a t i o n can then be determined by expressing the exchangeable cations (Ca,Na,K and Mg) as a per-centage of the c a t i o n exchange c a p a c i t y . S o i l Chemical C h a r a c t e r i s t i c s Summarized r e s u l t s of the chemical analyses were obtained by averaging values f o r the organi c , organic-mineral and mineral horizons i n a l l 166 p l o t s f o r each, of the i d e n t i f i e d s o i l c l a s s e s (Table 16). This system i s used i n place of the conventional horizon designations because the p r o f i l e s show con-s i d e r a b l e variation''". Local f a c t o r s , such as the complex p a t t e r n and e f f e c t s of ground i c e and the amount and character of organic m a t e r i a l at the surface leave t h e i r marks on the p r o f i l e morphology. In a d d i t i o n , p r o f i l e c h a r a c t e r i s -t i c s vary i n r e l a t i o n to parent m a t e r i a l , r e l i e f and time. Great v a r i a t i o n s cannot be expected because of the lack of v a r i a t i o n i n parent m a t e r i a l . R e l i e f i s more important as i t . r e l a t e s to drainage and degree of moisture r e t a i n e d i n i n d i v i d u a l h a b i t a t s . Previous a r c t i c s o i l s t u d i e s have given more s t r e s s to p h y s i c a l than.chemical p r o p e r t i e s , consequently few comparisons can be made. Where such comparisons are p o s s i b l e , the one outstanding d i f f e r e n c e i s always i n percent organic matter. Except, i n cases of raw s o i l s the percent organic matter i n the surface horizons i n the present study arc very high compared to e a r l i e r presented data (Douglas and Tedrow, 1959, 1960, H i l l and Tedrow, 1961, and Tedrow and H i l l , 1955). Organic matter content i s high i n the surface horizons of a l l . s o i l s with the exception of the O l i g o t r o p h i a G y t t j a , Snow Basin Rutmark and the A r c t i c Rawmark c l a s s e s . In a l l cases there i s a r a p i d decrease with depth. The t h i c k ness of the organic l a y e r i s an important feature of a l l the p o o r l y or non-drained s o i l s where i t ranges from raw residues to f i b r o u s d i s i n t e g r a t e d materi Where an organic-mineral l a y e r i s i n d i c a t e d , i t g e n e r a l l y suggests b u r i e d de-composed or undecomposed organic matter i n t e r m i n g l e d w i t h mineral matter. This b u r i e d l a y e r when p r e s e n t . i n c l a s s e s other than the A r c t i c Brown i s i n d i c a t i v e of a l l u v i a l d e p o s i t i o n or s o i l movement w i t h i n the p r o f i l e due to i n t e n s i v e f r o s t a c t i o n . While some of the b u r i e d organic matter may be a s s o c i a t e d w i t h downslope movement ( s o l i f l u c t i o n ) or c o n g e l i t u r b a t i o n (MacKay, 1958), I. The o r g a n i c , organic-mineral and mineral data f o r i n d i v i d u a l p l o t s i s pre-sented i n t a b u l a r form with the vegetation data i n the chapter d e s c r i b i n g the v e g e t a t i o n a l u n i t s . Table 16 Summary of s o i l chemical analyses of the organic,organic - mineral and mineral horizons. Averaged f o r each of the major d i v i s i o n s . Association A.f. E a. 0 a. E s. C r . S P- S c. S.ps. B.- C. B.- E.v. V.- B.g. B.- L.d. L. - D.a S.ph. Subassociation/Variation e a. . 5 P- c a . s a. b g. 3 P. b. - c. a c. e.v. s.r. «(a) «fb) b . - l . c.t. d- ^. r. d n. Organic matter [%) 55 8 63 1 70 3 87 1 81 3 91.3 56 9 67 8 72 9 71 8 79 8 74-5 51.6 54.8 63.8 55.0 60.7 71.5 Nitrogen (%) 1 26 1 11 1 36 1 28 1 55 1.37 1 47 1 55 1 3 1 13 1 29 1.2 1.34 1.13 1.35 1.1 1.16 1.53 G/N r a t i o 27 5 39 8 30 9 41 7 35 3 39.9 22 4 26 2 33 8 40 0 37 5 38.4 24.3 29-3 27.2 29.3 31.9 30.0 Adsorbed P (ppm) 21 11 13 13 12 19 26 24 24 13 24 15 11 23 30 24 24 21 Organic Na T ) 75 85 1 01 1 35 78 1.49 84 88 1 02 91 87 • 9 .8 .68 .77 .71 .79 .99 layer K+ ) Exchangeable 1 34 52 47 68 31 .84 1 83 1 13 1 09 77 94 .8 • 56 1.25 1.17 .74 • 95 .96 Ca** ) cations 15 8 8 6 10 5 19 7 10 5 21.4 22 1 21 3 20 1 17 2 21 6 13.2 27.7 16.9 18.0 6.7 13.5 30.6 ) meq) 7 6 2 0 3 2 3 6 1 5 5.5 6 4 5 4 6 4 4 4 5 0 3.4 10.9 5.8 5.7 1.9 3-3 8.0 CEC 62 4 95 1 72 4 126 4 123 3 117.7 103 8 87 0 96 6 121 6 107 8 121.6 115-6 100.4 133.6 82.9 101.9 102.4 PH 5 5 4 7 4 4 4 4 4 4 4-4 5 1 5 2 5 0 4 4 4 4 4-4 6.1 4.8 4.6 4.0 4-2 6.2 OM 3.7 19 9 17 1 27 3 22 1 21 3 20 7 18 5 25.6 32 8 17 5 24-7 18.5 18.0 19-5 23.8 22.8 14 9 2.9 N(*) • U 3, 34 89 38 73 49 49 .75 1 08 62 .61 • 43 • 59 .32 .66 .72 38 .1 C/N 20.0 18 7' 39 5 20 3 53 2 16 8 24 1 22 6 20.5 18 6 16 4 31.1 29.4 18.1 18.8 22.6 18.1 42 3 17.1 P ppm 12 12 7 13 8 5 19 16 25 10 16 6 8 5 11 16 14 18 7 Organic - Ma .73 65 66 73 54 49 81 1 01 .46 1 01 55 .71 .51 • 5 .69 .68 .65 66 .76 Mineral layer K .17 1 43 19 05 21 94 77 .67 34 25 .3 • 41 .2 .36 .47 .44 62 .17 Ca 4.8 3 1 4 0 7 2 6 3 8 6 18 6 11 9 10.9 11 1 10 9 6.9 9.4 12.1 2.3 8.5 18.4 11 0 .12 Mg .6 92 1 4 1 5 6 3 0 5 4 1 5 3.2 1 8 2 5 2.0 2.5 3.6 .6 1.6 2-4 2 9 .3 CEC 15.2 49 5 61 7 42 7 60 8 38 8 5,1 0 46 3 42.6 56 0 29 3 58.1 37.8 55.1- 39.7 58.1 56.6 40 2 20.4 PH 5.1 4 6 4 7 4 4 4 6 5 0 '5 9 4 8 ' 5-3 4 3 4 4 4-5 4.8 5-2 3.9 4.2 6.1 5 8 4.7 OM 1.2 3 2 7 9 1 3 2.8 3 9 3 7 3 0 3.2 4 7 7 6 2.4 3.8 5.1 3.6 3.7 3 .3 2 3 0.9 N(S6) .12 49 21 07 .17 25 18 12 .21 19 26 .1 .19 • 15 .13 .14 .12 12 .6 C/N 6.2 8 7 23 6 10 8 9.6 10 4 11 8 12 2 8.2 11 3 15 9 13-1 12.8 22.1 16.8 14.8 22.4 15 4 8.8 P ppm 5 7 14 7 12 11 8 7 8 9 14 5 6 6 10 9 8 8 3 Mineral Na • 85 64 51 71 .74 64 7 78 .58 54 81 .78 • 54 • 58 .71 .72 .71 69 .81 layer K .26 18 17 3 .18 21 . 28 5 .21 2 49 .16 • 25 .28 .2 .2 • 35 9.1 16 .11 Ca 3.0 4 8 5 2 6 1 3.6 6 1 7 5 9 8 7.5 5 4 8 7 6.3 5-3 5.1 1.2 4-5 1 9 .8 Mg • 5 1 0 • 1 1 1 0 1.3 1 8 1 6 2 0 1.6 65 1 4 1.0 1.6 1.6 .2 .7 2.5 4 .1 CEC 20.7 20 2 37 8 32 4 36.1 31 9 22 5 24 3 21.1 27 2 24 8 19.9 25.6 34-5 30.0 27.8 24.2 11 7 12.2 pH 4-5 4 6 5 0 4 4 4.0 4 8 5 1 5 3 5-3 5 0 4 7 4.7 4.7 4.6 4-5 4.7 6.5 4 8 4.9 *(a) vaccinio -betulosum glandulosae (fruticulosum) ) l(b) vaccinio - betulosum'glandulosae (fruticosum) concentrations at g r e a t e r depths have been a t t r i b u t e d to periods when the l o c a l c l i m a t e was warmer than that of the present day (Douglas and Tedrow, 1960). T o t a l n i t r o g e n i s high i n the m a j o r i t y of organic horizons and very low i n the mineral s o i l f o l l o w i n g c l o s e l y the p a t t e r n f o r organic matter. The h i g h e s t t o t a l n i t r o g e n averages are recorded i n the surface h o r i z o n of the A r c t i c Brown s o i l s . In the organic horizons the C/N r a t i o i s wide, ranging from 23.0 to 41.4 and i n the mineral horizons from 5.0 to 39.0. Holowaychuk et a l . (1966) re p o r t t h a t the content of n i t r o g e n r e l a t i v e to carbon i s lower i n Bog and Half-Bog s o i l s and increases with advanced decomposition i n western A l a s k a , t h i s does not appear to be the case with these subalpine s o i l s . At increased depths high C/N r a t i o s and low n i t r o g e n content i n d i c a t e b u r i e d organic matter w i t h l i t t l e or no decomposition t a k i n g p l a c e due to poor a e r a t i o n , low temperatures and high moisture content. This i s e s p e c i a l l y so i n the pooi'ly drained s o i l s . S o i l b a c t e r i a l a c t i v i t y i s very slow and i s one of the major reasons f o r the low amounts of a v a i l a b l e n i t r o g e n present i n the s o i l j u s t below the s u r f a c e , consequently n i t r a t e s are d e f i c i e n t i n many s o i l s o f the A r c t i c . De and Sarker, as reported by McNamara (1964) have shown that d e n i t r i f i c a t i o n occurs i n waterlogged s o i l s . The highest values of adsorbed phosphorus are found i n the A r c t i c Brown s o i l s (21-35 ppm), Greatest concentrations are present i n the organic l a y e r s of a l l s o i l s w i t h an appreciable decrease i n the organic - mineral and mineral horizons. S o i l r e a c t i o n i n the m a j o r i t y of s o i l s i s moderately to s t r o n g l y a c i d . There i s g e n e r a l l y l i t t l e v a r i a t i o n .with depth. In the A r c t i c Brown s o i l s t h i s i s due to the c l o s e p r o x i m i t y of non-calcareous parent m a t e r i a l to the surface. Only i n the case of the Lupino - Dryadetum * a l a s k e n s i s dryado - salicetosum r e t i c u l a t a e - glaucae a s s o c i a t e d w i t h the A r c t i c Brown shallow phase i s there a general decrease (pH 6.1 - 6.7). 97 Exchangeable c a t i o n s (Ca,Na,K and Mg) are present i n great e s t q u a n t i t i e s i n the organic h o r i z o n and decrease w i t h depth. Calcium i s the dominant b a s i c c a t i o n followed by magnesium,potassium and sodium i n the e ho r i z o n . The high values of exchangeable potassium and magnesium i n the surface h o r i z o n appears r e l a t e d to the high organic matter content and grea t e r c a t i o n exchange ca p a c i t y . In the mineral s o i l s sodium i s u s u a l l y present i n grea t e r q u a n t i t i e s . than potassium. An i n t e r e s t i n g f a c t o r revealed i n the analyses i s the high amount of exchangeable calcium (average 30.9 meq/100 gm) i n the dryado -saliceto s u m r e t i c u l a t a e - glaucae when l i t t l e calcareous parent m a t e r i a l was found i n the two study areas. This s u b a s s o c i a t i o n , however, i s g e n e r a l l y as-s o c i a t e d w i t h h i g h l y calcareous s o i l s i n Europe. McNamara (1964) has pointed out that e r r o r s can e a s i l y be made i n determining amounts of exchangeable cations because moisture c o n d i t i o n s are.so v a r i a b l e during the short a c t i v e season. Cation exchange c a p a c i t y (CEC) values vary between horizons and p r o f i l e s because o f d i f f e r e n c e s i n organic matter content. However, i n the surface horizons they are g e n e r a l l y very h i g h , while base s a t u r a t i o n i s low. With i n -creased depth C.E.C. values decrease and base s a t u r a t i o n i n c r e a s e s . The high C.E.C. values of the surface horizons i n d i c a t e that the exchange complex i s l a r g e l y s a t u r a t e d w i t h hydrogen (H+) r e s u l t i n g i n the moderately to s t r o n g l y a c i d c o n d i t i o n . The above r e s u l t s appear to i n d i c a t e general agreement with those of e a r l i e r workers w i t h regard to s o i l development. A problem a r i s e s i n deter-mining the tru e chemical s t a t u s of these s o i l s because of changing moisture c o n d i t i o n s during the p e r i o d of ve g e t a t i o n sampling. Few g e n e r a l i z a t i o n s may be made from the data regarding the s o i l s of t h i s r e gion of the Subalpine/ F o o t h i l l Zone. They i n c l u d e ; c a t i o n exchange c a p a c i t y decreases with depth; exchangeable calcium i s higher i n the surface horizons where, a f t e r i n i t i a l w aterlogging, a considerable degree of d r y i n g occurs; pH values are low and 98 in c r e a s e s l i g h t l y w i t h depth cn the upper slopes while i n the wetlands there i s l i t t l e v a r i a t i o n ; organic matter content drops r a p i d l y w i t h depth; where high amounts of exchangeable ca t i o n s are present i n the mineral s o i l they are u s u a l l y t i e d up i n c l a y l a t t i c e s and are, t h e r e f o r e , u n a v a i l a b l e to the p l a n t s . Parent. M a t e r i a l and Rock I d e n t i f i c a t i o n ' 1 " Pebble s i z e d rocks c o l l e c t e d i n s o i l samples at Canoe Lake and Trout Lake can be d i v i d e d i n t o two d i s t i n c t groups: those that are angular to sub-angular and are derived l o c a l l y , and the rounded to sub-rounded that have been c a r r i e d in from a d i s t a n t source. In the Cance Lake area the l o c a l l y derived, rocks are c l a s s e d as. ferruginous and sometimes a r g i l l a c e o u s quartz sandstones which i n some instances grade i n t o quartzose subgreywackes with the a d d i t i o n of l i t h i c fragments and mica. The rocks are characterized by an o v e r a l l b u f f colour w i t h t h e i r reddish-brown coloured l a y e r s present i n a randomly p a r a l l e l d i s t r i b u t i o n . The fragments tend to have a t a b u l a r shape with the cleavage c o i n c i d e n t w i t h the deeper coloured l a y e r s . In i t s present c o n d i t i o n the rock i s n o n - r e s i s t a n t and i n some cases f r i a b l e , i n a d d i t i o n i t i s g e n e r a l l y q u i t e porous and permeable. The i n d i v i d u a l quartz g r a i n s , v/hich comprise up to 80 percent o f the rock, are cemented by the c l a y s and i r o n oxides present. These grains are w e l l s o r t e d and g e n e r a l l y sub-rounded. Deposition of the source rocks i s considered to have occurred under r e l a t i v e l y s t a b l e marine c o n d i t i o n s during the Upper J u r a s s i c . Rocks de r i v e d from a d i s t a n t source i n c l u d e l i g h t coloured q u a r t z i t e s , darker micaceous q u a r t z i t e s , grey to black cherts with minor occurrences of greywacke, opal and v o l c a n i c s . These pebbles are approximately equidimensional and g e n e r a l l y rounded to w e l l rounded. A brachiopod f o s s i l was present i n one of the chert fragments. The source of these rocks i s unknown, however, grey and black cherts and q u a r t z i t e s have been reported to occur i n the Cambrian and 1. Rock samples were i d e n t i f i e d by Mr. R. MacDonald, Department of Geology, U n i v e r s i t y of B r i t i s h Columbia, and the f o l l o w i n g d e s c r i p t i o n i s based on tha t i n f o r m a t i o n . and O r d i v i c i a n rocks that outcrop to the south. Samples from Trout Lake may be s i m i l a r l y d i v i d e d i n t o two d i s t i n c t groups as above. Rocks d e r i v e d from a d i s t a n t source are the same as those i n the Canoe Lake sample i . e . q u a r t z i t e s and grey and black c h e r t s . The quartzose sandstones which appear to dominate the Canoe Lake sample are absent i n the Trout Lake area. L o c a l l y d e r i v e d rocks are classed as greywackes, greywacke s i l t s t o n e s and s h a l e s . The greywacke and greywacke s i l t s t o n e s are g e n e r a l l y dark grey to black i n c o l o u r , f a i r l y r e s i s t a n t , permeable and. w i t h an equidimensional t o t a b u l a r shape. T h e i r l o c a l d e r i v a t i o n i s i n d i c a t e d by t h e i r a n g u l a r i t y , how-ever, many have undergone some movement probably by stream a c t i o n . The g r a i n s i z e ranges from medium sand to s i l t . A l i g h t i r o n oxide s t a i n i s sometimes present, but cementation i s probably due to c l a y m i n e r a l s . The rocks of the area have been f r a c t u r e d and the f r a c t u r e s f i l l e d w i t h c r y s t a l l i n e quartz. The source of t h i s s i l i c a could be e i t h e r igneous or from s o l u t i o n w i t h i n ths sediments, but i t i s considered to be the l a t t e r . Present i n the s o i l p r o f i l e s were s e v e r a l pieces of c r y s t a l l i n e quartz derived from l o c a l l y wider v e i n s . The shale fragments are thought to have the same mineral composition as the greywacke s i l t s t o n e s but with a much smaller average p a r t i c l e diameter. . A s t r a t i g r a p h i c s e c t i o n across the study area would probably show a gradation from greywackes and greywacke s i l t s t o n e s to shales. The shale fragments are t a b u l a r and angular. T h i s , coupled w i t h t h e i r low r e s i s t a n c e , i n d i c a t e s l i t t l e or no t r a n s p o r t . These types of sediment are much l e s s mature than the quartzose sandstones. The environment of d e p o s i t i o n was probably marine i n a t e c h o n i c a l l y a c t i v e area where high rates of e r o s i o n and d e p o s i t i o n e x i s t e d . 100 CLASSIFICATION AND DESCRIPTION OF THE SOILS The lack of knowledge c f Canadian A r c t i c s o i l s makes i t necessary to f o l l o w designations p r e s c r i b e d by other q u a l i f i e d workers from other areas. An a r c t i c s o i l c l a s s i f i c a t i o n has been proposed by Tedrow et a l . (1958) and Tedrow and Cantlon (1958) i n which the s o i l p r o f i l e s are ar-ranged i n a drainage sequence, the A r c t i c Brown representing the mature wel l drained s o i l of the region. With r e s t r i c t e d drainage g l e i z a t i o n occurs immediately above the permafrost t a b l e . Complete s a t u r a t i o n of the p r o f i l e gives r i s e to a very high permafrost t a b l e and organic matter accumulates le a d i n g to bog formation. In grading from A r c t i c Brown to shallow w e l l drained c o n d i t i o n s there i s no change i n the type of s o i l -forming process, but only a r e d u c t i o n i n p r o f i l e t h i c k n e s s . A point i s reached where there are no acquired s o i l features as those a s s o c i a t e d w i t h L i t h o s o l s . The c l a s s i f i c a t i o n of A r c t i c Alaskan s o i l s by Tedrow and h i s co-workers covers only those a s s o c i a t e d w i t h chionophobous p l a n t communities, f o r those a s s o c i a t e d with chionophilous v e g e t a t i o n Kubiena's S o i l s of Europe has been a major source o f in f o r m a t i o n . S o i l p r o f i l e s from 166 p l o t s were described i n d e t a i l i n the f i e l d and samples taken f o r chemical, a n a l y s i s . The f o l l o w i n g d e s c r i p t i o n s summarize these data and ai~e used to i n d i c a t e p a r t i c u l a r morphological and develop-ment c h a r a c t e r i s t i c s of the s o i l types i n t o which i n d i v i d u a l p r o f i l e s have been placed. Nine major c l a s s e s of s o i l are recognized f o r t h i s r e g ion of the A r c t i c Subalpine Zone and these c l a s s e s represent twelve d i f f e r e n t s o i l types. In the f o l l o w i n g d e s c r i p t i o n s o i l s are described as c l o s e l y resembling types d e r i v e d from Kubiena (1953). i n Europe and s i m i l a r to those designated by Tedrow et a l . (1958) i n Alaska where a p p l i c a b l e . In Table 17 a p r o v i s i o n a l c l a s s i f i c a t i o n using nomenclature proposed by the above workers i s presented f o r the s o i l s . to f o l l o w page 100 TABLE 17 P r o v i s i o n a l S o i l • C l a s s i f i c a t i o n f o r the Low A r c t i c S u b a l p i n e / F o o t h i l l Zone I. Sub-Aquatic S o i l s (A) Sub-Aquatic not peat forming (a) O l i o g o t r o p h i c G y t t j a (B) Sub-Aquatic peat forming (a) Carex Fen • (b) Low-Centered Polygon Mire ( i ) Brown Moss ( i i ) Peat Moss I I . S e m i - T e r r e s t r i a l (Groundwater) S o i l s (A) S e m i - T e r r e s t r i a l Raw S o i l s (a) Snow Basin Rutmark (B) Anmoor-like S o i l s (a) Snow Basin Anmoor (b) Tundra Anmoor (C) S e m i - T e r r e s t r i a l Peat S o i l s (a) Tundra Moss (b) Peat Anmoor I I I . T e r r e s t r i a l (Land) S o i l s (A) T e r r e s t r i a l Raw S o i l s (a) A r c t i c Rawmark (B) Ranker-like S o i l s (a) Tundra Ranker (C) Rendzina S o i l s (a) A r c t i c Brown shallow phase (D) Brown Earths (a) A r c t i c Brown normal phase (Arctophiletum fulvae) (Caricetum a q u a t i 1 i s ) (Eriophoretum scheuchzeri) (Caricetum rari£.1 orae) (Sa1icet urn ps eudopo1aris) (S a 1 i c e t urn ch ami. s s on i. s) (Salicetum pulchrae) (Betulo - Chainaemoretum and Betulo Eriophoretum v a g i n a t i ) (Eriophoretum a n g u s t i f o l i i ) (Salicetum phlebophyllae and Lupino Dryadeturn * a l a s k e n s i s depauperatum (Betulo - Ledetum decumbentis cassiopeetosum tetragonae) (Lupino - Dryadeturn * a l a s k e n s i s ) (Vaccinio - Betuletum glandulosae and Betulo - Ledetum decumbentis) 1 Sub-Aquatic S o i l s (Kubiena, 1953) S o i l s always covered with water e i t h e r peat forming or not. Character-i z e d by simple p r o f i l e s t r u c t u r e . (A) Sub-Aquatic not peat, forming (Kubiena, 1953) Always c h a r a c t e r i z e d by a very simple p r o f i l e s t r u c t u r e i n which the B horizons are l a c k i n g . P r o f i l e development l i m i t e d to (A)C,AC or AG. M u l l humus i s completely l a c k i n g i n t h i s s o i l . (a) O l i g o t r o p h i c G y t t j a (Kubiena, 1953) Regosol (Tedrow et a l . , (195S) Low i n n u t r i e n t s , g e n e r a l l y w i t h shallow horizons i n a c i d immature waters, low i n e l e c t r o l y t e s . Four p r o f i l e s were s t u d i e d under t h i s category and a l l belonged to the Arctophiletum f u l v a e . S i t e s are present at Canoe Lake and Divided Lake and have a snow f r e e p e r i o d of 3-4 months. P r o f i l e s are l i m i t e d to an (A)C. In p l o t s 116 and 171 surface horizons are sandy-loam o v e r l y i n g t h i c k c l a y h o r i z o n s , and i n p l o t s 159 and 160 surface horizons c o n s i s t e d mainly of c l a y . Due to low p l a n t growth i n the shallow waters there i s a low supply of plant m a t e r i a l , t h e r e f o r e , low humus production. There i s r e l a t i v e l y strong o x i d a t i o n and l i t -t l e r e d u c t i o n . Percent organic matter i s very low, being no g r e a t e r than 4.6 percent i n the surface h o r i z o n ( p l o t 171). The s t r u c t u r e i n a l l p r o f i l e s i s loose, running e a s i l y through one's f i n g e r s when wet. The pH of both s o i l and water i s (moderately) to s t r o n g l y a c i d . P e r e n n i a l l y f r o zen ground v/as never reached i n any of the p l o t s . At Canoe Lake a compact bed of pebbles was encountered below the C h o r i z o n i n both s o i l p i t s . (B) Sub-Aquatic peat forming (Kubiena, 1953) C h a r a c t e r i z e d by a strong accumulation of l i t t l e decomposed p l a n t remains due to low h u m i f i c a t i o n . Buried peat l a y e r s w e l l preserved owing to prolonged i n e r t n e s s of the environment are e i t h e r parent m a t e r i a l f o r new s o i l formation or mere s u b s t r a t e . 102 (a) Carex Fen (Kubiena, 1953) Bog (Tedrow et a l . , 1958) S o i l s formed under stagnant freshwater with peat humus form, com-posed p r i m a r i l y of culms, leaves, rhizomes and roots of sedges. In the two study areas the Carex Fen s o i l s t u d i e d occurs i n the Caricetum a q u a t i l i s i n o l d lake beds and drainage pathways at lower e l e v a t i o n s . Snow fr e e p e r i o d i s estimated to be 3 1/2 months. The h a b i t a t s are c h a r a c t e r i z e d by a cool summer microclimate w i t h a wide range i n d i u r n a l temperatures and a cl o s e p l a n t cover. The s o i l s are waterlogged throughout the summer w i t l i sur-face water r e s u l t i n g p r i m a r i l y from snow melt. G r a v i t a t i o n a l water i s present only i n the o l d drainage pathways. The upper peat l a y e r i s composed of recognizable p l a n t remains derived from, i n p a r t , the e x i s t i n g v e g e t a t i o n . In t h i c k n e s s , i t v a r i e s from 12-35 cm. The u n d e r l y i n g m a t e r i a l i s l e s s f i b r o u s and approaches a muck-like c o n d i t i o n . The mineral horizons are composed mainly of s i l t and c l a y combinations with a low percent or organic matter. A e r a t i o n i s very poor due to the super-saturated c o n d i t i o n of the peat and the low temperatures that p r e v a i l at a l l times during the summer. No g l e i h o r i z o n i s d i s c e r n i b l e due to the high water t a b l e . What g l e i z a t i o n there i s can probably be found i n the upper part of the permafrost. O x i d i z i n g c o n d i t i o n s do p r e v a i l l a t e r i n the summer as the water t a b l e s l o w l y recedes. This r e s u l t s i n a y e l l o w i n g of the o l d root channels and other open-ings where access to oxygen i s af f o r d e d (Lutz and Chandler, 1965). A v a i l a b l e exchangeable c a t i o n s are low i n these Carex Fen s o i l s because of the slow r a t e of decomposition of p l a n t m a t e r i a l s due to low temperatures and are, t h e r e f o r e , considered as o l i g o t r o p h i c . Values are highest i n the upper peat l a y e r and decrease with depth f o l l o w i n g approximate changes i n percent organic matter. Cation exchange c a p a c i t y o f the s o i l i s g e n e r a l l y high and base s a t u r a t i o n low and are i n d i c a t i v e of the s t r o n g l y a c i d r e a c t i o n i n a l l h o r i z o n s . Depth.to permafrost appears r e l a t i v e l y c o n s i s t e n t f o r a l l . sampled p l o t s o f t h i s s o i l type, between 29-40 cm. Although Sphagnum mounds give the 103 impression l a t e r i n the summer, with d r y i n g out, of being s i m i l a r to the Hal f -Bog s i t e s t h e ' l e v e l o f permafrost appears constant and has no undulations. (b) Low-Centered Polygon Mire Half-Bog (Tedrow et a l . , 1958) S o i l formation peat forming c h a r a c t e r i z e d by a simple p r o f i l e s t r u c t u r e and considered o l i g o t r o p h i c - permesotrophic. S o i l s i n t h i s category are not discussed by Kubiena (1953). They are unique to a r c t i c regions because they develop as a r e s u l t of impeded drainage, i n t e n s i v e f r o s t a c t i o n and a high permafrost t a b l e . Wetness of the ground i s maintained by m e l t i n g snow and to a s l i g h t degree g r a v i t a t i o n a l water which re-s u l t s i n a high water-table. The water-table i n the Mire s o i l s recedes more r a p i d l y than that i n the Carex Fen so that moisture c o n d i t i o n s aire more hygric. than h y d r i c . Two v a r i a t i o n s are d i s t i n g u i s h e d ( K r a j i n a , 1967, personal communi-cation) the e a r l y stage or Brown Moss type and the l a t e r Peat Moss type, i ) Brown Moss S o i l s i n the Brown Moss v a r i a t i o n are commonly ted with the F.riophotetum scheuchzeri and are r e s t r i c t e d to e a r l y stage development i n low-centered polygons. The moss l a y e r i n the e a r l y stages of development.is domi-nated by Drepanocladus exannulatus and D_. aduncus with Sphagnum species becom-ing e s t a b l i s h e d as the surface water disappears. The type of topography a s s o c i -ated w i t h the Brown Moss i s not. common i n the S u b a l p i n e / F o o t h i l l Zone due to the i r r e g u l a r r e l i e f . Drainage i s v i r t u a l l y non-existent and surface water i s present throughout the summer. The waterlogged c o n d i t i o n prevents much organic decomposition and organic matter (mosses and sedges) tends 'to accumulate. Tedrow et a l . (1958) have pointed out a f e a t u r e of these s o i l s i s the presence of a black organic colour immediately above the permafrost, t h i s f e a t u r e was noted i n p l o t 94. Organic accumulations are always g r e a t e r than 22 cm and up to 48 cm i n t h i c k n e s s . In p l o t 53 an u n d e r l y i n g mineral h o r i z o n of high c l a y content i s present above and included i n the p e r e n n i a l l y frozen l a y e r . Chemical analyses show that where there are v a r i a t i o n s w i t h i n the p r o f i l e these f o l l o w approximate changes i n organic matter. Cation exchange ca p a c i t y i s higher i n the surface horizons and decreases g r a d u a l l y w i t h depth. Exchangeable c a t i o n s , dominated by calcium, were low throughout the p r o f i l e s . Percent n i t r o g e n and C/N r a t i o s are high and r e f l e c t the slow r a t e of de-composition i n these s o i l s . S o i l pH i s s t r o n g l y a c i d w ?ith l i t t l e v a r i a t i o n with depth. In more advanced stages of the Eriophoretum scheuchzeri s o i l c o n d i t i o n s approach the Peat Moss type, i i ) Peat Moss S i t e s considered as t r a n s i t i o n a l between low-centered and high-centered polygon topography are dominated by Caricetum r a r i f l o r a e . The Peat Moss s o i l i s not w e l l represented i n e i t h e r of the two study areas f o r reasons s i m i l a r to those given f o r the Brown Moss s o i l . Water-logging i s s t i l l char-a c t e r i s t i c of these s i t e s , however, the development o f m i c r o - r e l i e f f eatures allows f o r improved drainage and d r i e r c o n d i t i o n s w i t h i n Sphagnum dominated mounds. Woody species are present i n i n c r e a s i n g numbers on these mounds and r e f l e c t the s e m i - t e r r e s t r i a l c o n d i t i o n of the r a i s e d m i c r o - r e l i e f . Frost a c t i o n p l a y s a v i t a l r o l e i n producing the c h a r a c t e r i s t i c m i c r o - r e l i e f features a s s o c i -ated with these h a b i t a t s . A e r a t i o n i s improved and organic matter decomposition and h u m i f i c a t i o n i s more a c t i v e i n the Caricetum r a r i f l o r a e due to the more h y g r i c c o n d i t i o n s . Surface water i s never present i n these s i t e s a f t e r mid-August. Exchangeable c a t i o n s , e s p e c i a l l y c alcium, are a v a i l a b l e i n g r e a t e r q u a n t i t i e s and C/N and percent n i t r o g e n values are lower than i n the Brown Moss and i n d i c a t e the more a c t i v e c o n d i t i o n of t h i s s o i l type. Cation exchange c a p a c i t y i s high throughout the p r o f i l e s . S o i l r e a c t i o n i s s t i l l s t r o n g l y acid, with l i t t l e v a r i a t i o n i n depth. Permafrost i s c l o s e to the surface and, i n many cases, included part of the organic l a y e r i n i t s upper surface. 105 I I . S e m i - T e r r e s t r i a l (Groundwater) S o i l s (Kubiena , 1953) Not o r t e m p o r a r i l y . c o v e r e d by water , however, comple te ly or p a r t i a l l y water logged . Major source o f parent m a t e r i a l f o r humus format ion d e r i v e d from h i g h e r p l a n t s . (A) S e m i - T e r r e s t r i a l Raw S o i l s (Kubiena, 1953) S o i l s low i n humus, but w i t h a s l i g h t to s t rong g l e i z a t i o n . The s o i l s are water logged when f ree o f snow or su r face water . (a) Snow B a s i n Rutmark (Kubiena, 1953) (F igure 26) L i t t l e g leyed a l l u v i a l s o i l o f the h igh mountains and a r c t i c reg ions a s s o c i a t e d w i t h very l a t e snow. Per iods o f v e g e t a t i o n a l a c t i v i t y r e -s t r i c t e d to 2-6 weeks. P l a n t coverage i s always sparse and never c l o s e d . Only f i v e p l o t s were s t u d i e d and they occurred i n ihe S a l i c e t u m pseudo-p o l a r i s . A l l s i t e s are i n s h e l t e r e d areas w i t h deep snow accumula t ion and only on south to east f a c i n g s l o p e s . The s o i l i s covered by snow 10 1/2 - 11 1/2 months o f every yea r . Dur ing snow melt the s o i l adsorbs l a rge q u a n t i t i e s o f melt water and i s t e m p o r a r i l y wate r logged . S o i l sur face m a t e r i a l s are c o n s t a n t l y moving downslope due to snow creep i n summer and e r o s i o n by the many r i v u l e t s c r o s s i n g the exposed s o i l sur face a f t e r snow me l t . P r e c i p i t a t i o n , i n the form o f r a i n du r ing the summer g e n e r a l l y has l i t t l e e f f e c t on these s i t e s o ther than compacting the snow. > A ve ry weak sur face (A) h o r i z o n i s p re sen t , however, i t s development i s l i m i t e d to a darkening o f the upper 3-5 cm o f su r face s o i l . The darkening i s p r i m a r i l y a r e s u l t o f f i n e o rgan ic mat ter d e p o s i t i o n on the snow and i t s i n f i l t r a t i o n i n t o the s o i l f o l l o w i n g snow me l t . Underneath i s e i t h e r a s l i g h t l y g leyed o r ungleyed g e n e r a l l y grey-brown co lou red (C) h o r i z o n . Percent o rgan ic mat ter v a r i e s c o n s i d e r a b l y , ranging from a low o f 4.8 to a h igh o f 61 .7 . Th i s l a t t e r s i t e c l o s e l y resembles .the S a l i c e t u m chamisson i s . C a t i o n exchange c a p a c i t y i s low as are the exchangeable ca t ions (Ca,Mg,K and Na) . S o i l pH i s s t r o n g l y a c i d i n the surface h o r i z o n and increases w i t h depth, becoming mod-e r a t e l y a c i d . Permafrost was never reached i n any s o i l p i t , due to the s o l i d mass of packed unconsolidated parent m a t e r i a l encountered every time at depths from 2 1 - 7 5 cm. Figure 26. Snow Basin Rutmark s o i l (Kubiena, 1955) a s s o c i a t e d with the Salicetum pseudopolaris. The upper (A) h o r i z o n i s d i s t i n g u i s h e d by a darkening of the surface s o i l . The r e l a t i v e l y deep C horizon i s l i g h t coloured and shows evidence of g l e y i n g . (Photo by K r a j i n a ) (B) Anmcor-like S o i l s (Kubiena, 1953) S o i l s w i t h a d i s t i n c t humus horizon o r , f a i l i n g t h a t , at l e a s t with a d i s t i n c t l y developed B h o r i z o n , s t r o n g l y gleyed, under the i n f l u e n c e of impeded water due to low p e r m e a b i l i t y of the s o i l . S o i l s waterlogged f o r long periods of the year. G y t t j a - l i k e humus has c h a r a c t e r i s t i c 'inky' s m e l l . (a) Snow Basin Anmcor (Kubiena, 1953) (Figure 27) S o i l s o c c u r r i n g i n s h e l t e r e d depressions and cut banks, covered by snow f o r most of the year. P r i o r t o , and a f t e r , snow removal s o i l s are 107 t e m p o r a r i l y waterlogged, a f t e r which the s o i l s e x h i b i t a c e r t a i n m o i s l -ness but no waterlogging. S i t e s c h a r a c t e r i z e d by p r o s t r a t e willows and herbaceous p l a n t s of a l p i n e meadows. Snow Basin Anmoor s o i l s occur only i n the Salicetum chamissonis i n s h e l t e r e d areas along creek banks and lake shores at e l e v a t i o n s between 1060-1800 f t and always with e a s t e r l y to s o u t h e r l y exposures. Snow f r e e p e r i o d i s estimated to be between 2-6 weeks. A l l s i t e s are c h a r a c t e r i z e d by l u x u r i a n t plant growth during the short snow f r e e p e r i o d . S o i l s are g e n e r a l l y f i n e - t e x t u r e d and s t r a t i -f i e d by sedimentation from wind-blown m a t e r i a l s on adjacent exposed ridges and escarpments. P r o f i l e development i s c h a r a c t e r i s t i c a l l y A-B-C. The dark grey humus ho r i z o n v a r i e s between 3-8 cm i n depth and o v e r l i e s s e v e r a l gley horizons that are mainly blue-grey i n colour with numerous r u s t specks. Texture of the B h o r i z o n i s mainly s i l t y loam K i t h v a r y i n g amounts of f i n e rock d e b r i s . Root p e n e t r a t i o n i s between 25-56 cm becoming sparse at lower depths. Figure 27. Snow Basin Anmoor s o i l (Kubiena, 1953) a s s o c i a t e d with the Salicetum chamissonis. The dark grey humus hor i z o n i s evident i n the upper r i g h t hand corner. The gley horizons are c l e a r l y d i s -t i n g u i s h e d . Root p e n e t r a t i o n i s to approx. 30 cm. (Photo by Lambert) 108 Chemical analyses i n d i c a t e a high percentage.of organic matter i n the A hor i z o n (between 48-87 percent) i n a l l p l o t s except p l o t 143. Cation exchange c a p a c i t y and percent base s a t u r a t i o n are both high. Values f o r the b a s i c c a t i o n s (Ca,Mg,K and Na) are high i n the surface horizon and as the pH i s g e n e r a l l y mod-e r a t e l y a c i d i t must be i m p l i e d that a c e r t a i n percentage must be a v a i l a b l e as a f r e e source. Lower q u a n t i t i e s , but s t i l l h i g h, i n the B ho r i z o n suggest the b a s i c c a t i o n s are mostly u n a v a i l a b l e and p r o b a b l y ' f i x e d between s i l t y - c l a y l a t -t i c e s . The s o i l edaphotope i s considered to be mesotrophic to permesotrophic. S o i l r e a c t i o n i s v a r i a b l e . I f the surface h o r i z o n i s s t r o n g l y a c i d there i s a decrease with depth and i f i t i s moderately a c i d then i t always appears to i n -crease i n a c i d i t y with depth. In the l a t t e r case i t would suggest, that water-logging by the ground water causes l e a c h i n g . P e r e n n i a l l y frozen ground was never reached i n any of the f i f t e e n s o i l p i t s that ranged i n depth, from 40-70 cm. In the low l y i n g snow bed h a b i t a t s i n the Canoe Lake and Divided Lake region the anmoor ch a r a c t e r of the s o i l i s l o s t . The ve g e t a t i o n i s dominated not by S a l i x chamissonis, but by such species as Equisetum arvense ( p l o t s 148 and 170), Festuca a l t a i c a ( p l o t 162), Carex montanensis ( p l o t 145) and A r c t a g r o s t i s  l a t i f o l i a ( p l o t 157). In these s i t e s the humus approaches a m u l l - l i k e moder form (Mull-Gley S o i l , Kubiena 1953). The s o i l s are always moist and never, or only t e m p o r a r i l y , waterlogged. The t e x t u r e o f the (G) gley h o r i z o n i s u s u a l l y loamy and clayey. (b) Tundra Anmoor (Kubiena, 1953) Waterlogged s o i l of shrub dominated drainage pathways. C h a r a c t e r i z e d by a muddy d y s t r o p h i c anmoor formation and a very t h i c k a c t i v e l a y e r . S o i l s i n t h i s category are a s s o c i a t e d w i t h the s l i g h t l y chionophilous shrub Salicetum pulchrae which i s present i n drainage pathways and on lake edges' at e l e v a t i o n s ranging from. 1075-1825 f t . The m a j o r i t y of the s i t e s are on. gradients of 5-15° w i t h e a s t e r l y or s o u t h e r l y exposures. Snow accumulation i s great w i t h a snow f r e e p e r i o d of 6-10 weeks. Shrub growth i s i n excess of s i x f e e t w i t h herbaceous v a s c u l a r p l a n t s dominating the C l a y e r . The moss l a y e r (D) i s conspicuous by the absence of'Sphagnum species and can probably be r e l a t e d to the f r e e f l o w i n g drainage water present throughout most of the summer, e s p e c i a l l y at lower e l e v a t i o n s . This drainage water deposits both or-ganic and i n o r g a n i c m a t e r i a l s throughout the h a b i t a t s during the high water or f l o o d p e r i o d . P r o f i l e s are v a r i a b l e because of the annual d e p o s i t i o n of m a t e r i a l s . The organic h o r i z o n i s g e n e r a l l y t h i n (3-10 cm t h i c k ) and b l a c k i s h i n c o l o u r with a pH range from 4.9 to 5.5. In two p l o t s (149 and 165) the pH was 6.2 Under-l y i n g the A h o r i z o n are u s u a l l y one or more brown coloured gley horizons that are predominantly clay-loam to c l a y - l i k e i n t e x t u r e . The p l o t s have a high water t a b l e due to c o n t i n u a l seepage. Aeration i n the p r o f i l e s i s mostly very poor. S a l i x p u l c h r a leaves and other p l a n t m a t e r i a l s that accumulate on the ground during the autumn are packed down by snow i n w i n t e r , at which time l i t t l e or no decomposition occurs. The f o l l o v / i n g s p r i n g , i f f l o o d waters do not remove the compressed organic d e b r i s , a l l u v i a l m a t e r i a l s are deposited over them and f u r t h e r breakdown i s prevented. I t i s , t h e r e f o r e , not uncommon to f i n d unde-composed p l a n t remains i n the gley h o r i z o n s . In the s o i l p r o f i l e i n p l o t 141 the organic h o r i z o n i s o v e r l a i n by a clay-loam h o r i z o n 3 cm t h i c k . (C) S e m i - T e r r e s t r i a l Peat S o i l s (Kubiena, 1953) Surface l a y e r of w e l l developed peat. S i t e s p o o r l y drained and waterlogged i n e a r l y p a r t of summer. (a) Tundra Moss (Kubiena, 1953) Meadow Tundra (Tedrow et a l . , 195S) (Figure 28) S o i l c h a r a c t e r i s t i c of hummocky slopes that are s t r o n g l y a f f e c t e d by i n t e n s i v e f r o s t a c t i o n . Permafrost.surface uneven but g e n e r a l l y c l o s e to the ground surface. 110 R e l a t i v e l y high C/N r a t i o s are found i n the gley horizons with c o r r e s -pondingly low t o t a l n i t r o g e n values. Cation exchange ca p a c i t y and the major exchangeable c a t i o n s (Ca,Mg,K and Na) are g e n e r a l l y high i n the organic l a y e r and suggest a f r e e source i s made a v a i l a b l e by a l l u v i a l d e p o s i t i o n . A l l values decrease r a p i d l y i n the gley h o r i z o n s , but where a high q u a n t i t y i s recorded i t i s probably not a c c e s s i b l e to the p l a n t roots or t i e d up i n the c l a y l a t t i c e and not i n an a v a i l a b l e form. S o i l r e a c t i o n remains a v a i l a b l e but f a i r l y constant throughout each p r o f i l e and i s moderately to s t r o n g l y a c i d . This would suggest that the pH i s c o n t r o l l e d by the groundwater. Two a s s o c i a t i o n s (Betulo - Eriophoretum v a g i n a t i and Betulo - Chamaemoretum) are a s s o c i a t e d w i t h the s o i l of t h i s category and both occur at lower e l e v a t i o n s -below 1500 f t . Slope gradients vary but are g e n e r a l l y moderate to shallow. Drainage i s , t h e r e f o r e , poor and the s o i l s waterlogged (hydric) during and j u s t a f t e r snow melt, becoming h y g r i c during the summer. A hummock-depression micro-r e l i e f i s common i n both a s s o c i a t i o n s , however, i t i s more pronounced i n the Betulo - Eriophoretum v a g i n a t i . The snow f r e e p e r i o d v a r i e s from between 10-12 weeks depending on the depth of the depression. The p r o f i l e s are c h a r a c t e r i z e d by the presence of moss (mainly Sphagnum) o v e r l y i n g one or more compact l a y e r s of raw humus or o l d moss. The upper moss l a y e r r e t a i n s l a r g e q u a n t i t i e s of moisture and acts as an i n s u l a t i o n and pre-vents deep thawing. Consequently, the p e r e n n i a l l y frozen ground i s always close to the su r f a c e . The a c t i v e l a y e r , however, i s deeper under the hummocks and/or Eriophorum vaginatum tussocks than i n the depressions. Below-the organic h o r i -zons there are u s u a l l y one or more d i s c e r n i b l e gley horizons depending on the p o s i t i o n o f the permafrost. S o i l textm^e i s v a r i a b l e depending on the degree of s o i l movement ( c o n g e l i t u r b a t i o n ) . In the Betulo - Chamaemoretum the mineral s o i l i s mainly s i l t y - l o a m , and i n the Betulo - Eriophoretum v a g i n a t i i t i s s i l t y - c l a y or s i l t y - l o a m . Figure ?8. Tundra Moss s o i l (Kubiena, 1 9 5 3 ) , Meadow Tundra (Tedrow et a l . 1 9 5 8 ) a s s o c i a t e d w i t h the Betulo - Chamaemoretum. Surface l a y e r of l i v i n g Sphagnum o v e r l y i n g raw humus or o l d Sphagnum. Depth to permafrost 27 cm. Sampled August 4 / 6 5 . (Photo by Kr a j i n a ) B i o l o g i c a l l y the s o i l s are i n e r t . The unfavourable c o n d i t i o n s such as the presence of permafrost c l o s e to the s u r f a c e , long snow d u r a t i o n , p e r s i s t e n t waterlogging, f r o s t a c t i o n and wind help to favour low a e r a t i o n , a c i d i f i c a t i o n and a lack of n u t r i e n t s and bases. The chemical analyses c l e a r l y i n d i c a t e the high c a t i o n exchange c a p a c i t y and low base s a t u r a t i o n . Exchangeable c a t i o n s , dominated by calcium, are low i n the surface horizons and decrease with depth. In the Betulo - Chamaemoretum exchangeable ca t i o n s are higher i n the surface h o r i z o n and t h i s i s r e l a t e d to the increase i n le a c h i n g by the f r e e f l o w i n g drainage water passing over the ground surface o f the alnetosum c r i s p a e from the upper slopes i n the e a r l y part of the summer. T o t a l n i t r o g e n , although low i n the mineral h o r i z o n s , i s high i n the organic h o r i z o n (average 1 . 1 6 p e r c e n t ) . C/N r a t i o s are high i n the surface horizons and are a good j u d i c a -t i o n of the slow r a t e of decomposition i n these Tundra Moss s o i l s . A C/N r a t i o of 102.0, the highest present i n the organic h o r i z o n , occurred i n p l o t 54 and c o n s i s t e d of l i g h t brown f i b r o u s peat. Douglas and Tedrow (1959) i n studies on r a t e s of organic matter decomposition i n a r c t i c s o i l s concluded that w h i le they were slow they are i n f l u e n c e d more by temperature than moisture content. S o i l r e a c t i o n i s s t r o n g l y to very s t r o n g l y a c i d i n the m a j o r i t y of the p r o f i l e s , however, the pH does increase w i t h depth. The s o i l edaphotope i s considered to be s u b o l i g o t r o p h i c to submesotrophic. In the Betulo - Eriophoretum v a g i n a t i salicetosum r e t i c u l a t a e present at higher e l e v a t i o n s , p r o f i l e morphology i s s i m i l a r to those at lower e l e v a t i o n s . However, as i s pointed out i n the vege t a t i o n s y n t h e s i s , these s i t e s are bordered by more calcareous communities (Lupino - Dryadeturn * a l a s k e n s i s ) . Drainage water from these calcareous slopes f l o w i n g i n t o the salicetosum r e t i c u l a t a e are re-t a i n e d and are probably an important source f o r b a s i c c a t i o n s . The c a t i o n ex-change c a p a c i t y i s high as i s a l s o base s a t u r a t i o n (over 50 p e r c e n t ) . Ex-changeable c a t i o n s (Ca,Mg,K and Na) have high values compared to the lower e l e v a t i o n s , and the s o i l pH i n the surface horizons i s only s l i g h t l y a c i d but decreases w i t h depth. The s o i l o f t h i s s u b a s s o c i a t i o n i s considered mesotrophic. (b) Peat Anmoor (Kubiena, 1953) S o i l formation from p a r t i a l l y drained peat l a y e r w i t h f l u c t u a t i n g water l e v e l . P l a n t cover i s g e n e r a l l y closed. S o i l s i n t h i s category are commonly a s s o c i a t e d w i t h the Eriophoretum a n g u s t i f o l i i ' w h i c h occurs at both high and low e l e v a t i o n s i n drainage pathways i n the subalpine zone. Gradients on the upper slopes range from 2-13° with e a s t e r l y exposures. On the lower slopes gradients are n e g l i g i b l e (0-2°). The snow f r e e p e r i o d i s from 3 1/2 to 4 months. Free f l o w i n g drainage water i n the s p r i n g i s . more r a p i d on the slopes than at lower e l e v a t i o n s , and the s i t e s are g e n e r a l l y b e t t e r drained by the end of the summer. 113 The s o i l s are c h a r a c t e r i z e d by having e i t h e r a t h i c k accumulative sur-face h o r i z o n of raw f i b r o u s reddy-brown peat or very l i t t l e at a l l ( p l o t s 42 and 152). In the l a t t e r few p l a n t remains are present i n the predominantly s i l t y - c l a y s u rface s o i l h o r i z o n . Under the accumulated peat h o r i z o n there i s al s o a s i l t y - c l a y (C) ho r i z o n . Buried undecomposed organic l a y e r s of very small t h i c k n e s s and s i z e are present i n the mineral h o r i z o n . Under i c e f r e e c o n d i t i o n s , there develops from the i n e r t peat humus an a c t i v e humus formation with good decomposition. When the peat anmoor i s present i n a re g i o n o f continuous permafrost the y e a r l y a l t e r n a t i o n of waterlogging and dryin g out i s reduced t o a p e r i o d of no longer than four months, the p e r i o d when the a c t i v e l a y e r i s f r e e from i c e . E d a p h i c a l l y t h i s s o i l i s r e l a t i v e l y low i n n u t r i e n t s and can be c l a s s i f i e d as between o l i g o t r o p h i c and permesotrophic. Cation exchange c a p a c i t y of the A ho r i z o n v a r i e s from 39.4 to 149.0 meq/100 gm and a c c o r d i n g l y the q u a n t i t i e s of exchangeable ca t i o n s i n d i c a t e a v a r y i n g de-gree of hydrogen (H+) s a t u r a t i o n . Lower q u a n t i t i e s o f a v a i l a b l e cations with increased depth r e f l e c t a decrease i n percent organic matter. S o i l r e a c t i o n i s g e n e r a l l y s t r o n g l y a c i d , however, i n p l o t 49 the pH of the surface peaty h o r i -zon was 7.2 and dropping to 4.2 between 13-28 cm below the su r f a c e . As t h i s p l o t was analyzed i n mid-June, i t probably r e f l e c t s the r e c e n t l y f r e e f l o w i n g drainage water that had drained through the s i t e . I I I . T e r r e s t r i a l (Land) S o i l s (Kubiena, 1953) S o i l formation p r a c t i c a l l y never covered with water or waterlogged, t r a n -s i t i o n s to s e m i - t e r r e s t r i a l d i v i s i o n may have g l e y i n g . (A) T e r r e s t r i a l Raw S o i l s (Kubiena, 1953) Occurring e i t h e r i n very dry and hot regions as w e l l as very c o l d regions. Appearing above the tundra zone as a c l i m a t i c form, but a l s o reaching i n t o the tundra zone. P h y s i c a l weathering predominates over chemical weathering. Humus development r a r e , with p r o f i l e development v e r y . v a r i a b l e . S o i l s always w e l l drained. 114 In the a r c t i c subalpine zone s o i l s of. t h i s category are present on ex-posed r i d g e tops and escarpments. P r o f i l e .development i s g e n e r a l l y r e s t r i c t e d by the i n s t a b i l i t y of the surface m a t e r i a l s and the presence o f only l i m i t e d amounts of organic m a t e r i a l s . The snow f r e e p e r i o d i s longer on these higher elevated more exposed s i t e s than any other w i t h i n t h i s zone. The a c t i v e l a y e r i s t h i c k due to the degree of slopes and coarseness of the m a t e r i a l s . (a) A r c t i c Rawmark (Kubiena, 1953) L i t h o s o l (Tedrow et a l . , 1958) Coarse t e x t u r e d and w e l l drained s o i l s on non-calcareous parent. m a t e r i a l . Owing to rawness o f the s o i l and low chemical weathering no g l e y i n g occurs. Continuous movement of m a t e r i a l s ( f r o s t heaving) i s a r e s u l t o f in t e n s e a l t e r n a t i o n o f f r e e z i n g and thawing. In a d d i t i o n to the A r c t i c Rawmark s o i l s described below, other s o i l s having c h a r a c t e r i s t i c s of Rawmark-like s o i l s have been noted. They are a s s o c i a t e d with t r a n s i t i o n s c l o s e to the Salicetum phlebophyllae and i n c l u d e the A r c t i c Hamada Rawmark and S t r u c t u r e Rawmark. Four p r o f i l e s were s t u d i e d i n the Salicetum phlebophyllae. A l l s i t e s were on n o r t h e r l y exposed slopes w i t h a snow f r e e p e r i o d o f 4 1/2 months. The pro-f i l e s g e n e r a l l y c o n s i s t of a t h i n p o o r l y developed A h o r i z o n (under mats of higher p l a n t s o n l y ) , a loose C h o r i z o n u s u a l l y l i g h t i n colour and a hard parent rock (C2 h o r i z o n ) . Percent organic matter i s very low, being no greater than 4.1 percent i n any one surface h o r i z o n . The mineral s o i l i s n e a r l y always coarse and c o n s i s t s mainly o f a stony g r i t t y sand. In contrast to the low chemical weathering, the p h y s i c a l weathering i s important, being a c t i v e i n wi n t e r and sum-mer. In wi n t e r the abrasive winds and hard i c e c r y s t a l s are instrumental i n eroding f i n e f r a c t i o n s from exposed parent m a t e r i a l and v e g e t a t i o n . During the snow f r e e p e r i o d freeze-thaw c y c l e s and wind are primary sources o f mechanical breakdown. Chemical analyses show that the s o i l i s very poor i n a v a i l a b l e b a s i c c a t i o n s and i s , t h e r e f o r e , considered o l i g o t r o p h i c . The a c t i v e l a y e r i s g e n e r a l l y very t h i c k although d i f f i c u l t to determine due to the coarseness of the unconsolidated parent m a t e r i a l . In p l o t 62 a s i l t y - c l a y loam i s present at a depth of 44 cm. S o i l pH i s moderately to s t r o n g l y a c i d w i t h l i t t l e v a r i a t i o n i n depth.. S o i l s i n the Lupino - Dryadetum * a l a s k e n s i s (de-pauperatum) on l e s s ex-posed s i t e s at high e l e v a t i o n s i n the Subalpine Zone are a l s o considered as belonging to the A r c t i c Rawmark type. Four p r o f i l e s were s t u d i e d . In a l l pro-f i l e s organic matter i n the upper h o r i z o n i s greater (13 percent) than that i n the Salicetum phlebophyllae. Exchangeable ca t i o n s (Ca,Mg,K and Na) and c a t i o n exchange c a p a c i t y values are low. S o i l r e a c t i o n i n p l o t s 2 and 73 i s s t r o n g l y a c i d and only s l i g h t l y a c i d i n p l o t s 25 and 137. These l a t t e r two are con-s i d e r e d as t r a n s i t i o n a l between the A r c t i c Rawmark and the A r c t i c Brown shallow phase. (B) R a n k e r - l i k e S o i l s (Kubiena, 1953) S o i l formation, low i n lime, whose humus h o r i z o n l i e s immediately on the parent m a t e r i a l which c o n s i s t s u s u a l l y of lime d e f i c i e n t s i l i c e o u s or s i l i c a t e rock (AC s o i l s i n parent m a t e r i a l low i n l i m e ) . (a) Tundra Ranker (Kubiena, 1953) S o i l without waterlogging or peat formation, but. with a very i n a c t i v e humus formation of matted l i t t l e decomposed p l a n t remains o c c u r r i n g on dry tundra. Few s o i l p r o f i l e s can be considered as Tundra Ranker, those that are as-s o c i a t e d w i t h the Betulo - Ledetum decumbentis cassiopeetosum tetragonae. Where present they are c h a r a c t e r i z e d by a t h i n matted brown, mineral d e f i c i e n t surface h o r i z o n (A ) o v e r l y i n g a more or l e s s mineral r i c h b l a c k i s h A^ h o r i z o n which l i e s d i r e c t l y . o n the C h o r i z o n c o n s i s t i n g o f i c e shattered parent rock. Chemical weathering i s of r e l a t i v e l y minor importance.with a tendency to strong a c i d i -f i c a t i o n . P e r e n n i a l l y frozen ground i s present but because of the coarse unconsolidated parent m a t e r i a l , i t i s not c l o s e to the.surface. Decomposition 116 and h u m i f i x a t i o n are g e n e r a l l y lew because the.dominant species contain de-composition impeding substances. These s o i l s c l o s e l y resemble the 'arncrphorus tundra s o i l s o f the s o l i -f l u c t i o n s l o p e 1 described by McNamara (1964) i n northern Alaska. A d d i t i o n a l s t u d i e s are needed before any d e f i n i t e statements can be made concerning the true presence o f t h i s s o i l type. (C) Rendzina S o i l s (Kubiena, 1953) Humus b l a c k i s h , dark-grey to l i g h t grey coloured. S o i l u s u a l l y calcareous to extremely calcareous. Chemical weathering i s poor w i t h p h y s i c a l weathering predominant i n a r c t i c r e g i o n s . (a) Brown Rendzina (Kubiena, 1953) A r c t i c Brown shallow phase (Tedrow et a l . , 1958) Re n d z i n a - l i k e (McVean, 1964) These s o i l s are rare because o f the s c a t t e r e d occurrence o f calcareous rocks. They are u s u a l l y shallow of almost n e u t r a l r e a c t i o n w i t h Rendzina-l i k e features but are not n e c e s s a r i l y true Rendzina. On somewhat s h e l t e r e d r i d g e slopes and escarpments i n the two study areas are h a b i t a t s supporting Lupino - Dryadeturn * a l a s k e n s i s dryado - salicetosum r e t i c u l a t a e - glaucae. Tedrow et a l . (1958) consider t h i s s o i l type to be c l o s e l y r e l a t e d to the A r c t i c Brown shallow phase. The s o i l i s present where bedrock i s c l o s e to the surface and the s i t e s are w e l l drained. The surface h o r i -zon o v e r l i e s l i t t l e weathered sandy to s i l t y mineral l a y e r s which i n d i c a t e a degree of me l a n i z a t i o n w i t h moder formation. High concentrations or organic matter are present i n the t h i n A hor i z o n and decrease r a p i d l y w i t h depth. This decrease with depth can be r e l a t e d , i n p a r t , to fewer roots present at the lower depths (Tedrow and H i l l , 1955). The p r o f i l e s u s u a l l y d i s p l a y narrow colour v a r i a t i o n s , the upper ho r i z o n i s dark brown grading to yellow-brown. Small stone fragments are present throughout the p r o f i l e and are c o n t i n u a l l y forced to the surface by i n t e n s i v e f r o s t a c t i o n . The s o i l s thaw e a r l y i n l a t e s p r i n g and remain i n an unfrozen s t a t e throughout the summer. The a c t i v e l a y e r i s t h i c k as a r e s u l t of good drainage and there i s a dry f r o s t c o n d i t i o n during the winter"'". A high percentage of the a c t i v e l a y e r c o n s i s t s of i c e - s h a t t e r e d unconsolidated parent m a t e r i a l . P h y s i c a l weathering i s more intense than chemical weathering i n these p r o f i l e s due to low temperatures and i n s u f f i c i e n t moisture which r e s t r i c t micro-b i a l a c t i v i t y to a minimum. In the s u r f a c e horizons c a t i o n exchange c a p a c i t y i s high and base s a t u r a t i o n very i n c o n s i s t e n t , ranging from 25-81 percent. Exchangeable c a t i o n s w i t h calcium dominating, are present i n greatest q u a n t i t y i n the organic h o r i z o n and decrease r a p i d l y w i t h depth. This s o i l edaphotope i s considered as mesotrophic. A magnesium value of 20.3 meq/100 gm, the highest i n any organic h o r i z o n , occurred i n p l o t 133. S o i l pH i s high f o r the surface horizons of the dryado - s a l i c e t o s u m r e t i c u l a t a e - glaucae ranging from 5.4 to 7.3. McVean (19G4) has described the s o i l s o f the Dryas - S a l i x r e t i c u l a t a stands i n Scotland as R e n d z i n a - l i k e owing to the high calcium content and i r r i -g a t i o n from nearby calcareous rock. K r a j i n a (personal communication) found that c e r t a i n p a r ts of exposed rocks t h a t were subjected to the HCL t e s t gave p o s i t i v e r e a c t i o n s f o r calcium. This would account f o r the more calcareous nature of the surface h o r i z o n and, at the same time, t h e i r s l i g h t l y a c i d c o n d i t i o n . (D) Brown Earths (Kubiena, 1953) N e u t r a l to moderately a c i d A (B) C s o i l . B horizons are i n d i c a t i v e of deep reaching chemical weathering with good a e r a t i o n and not excessive moisture. There are many t r a n s i t i o n s between the A r c t i c Brown and other types. 1. M i n e r a l matter i n a frozen s t a t e , but c o n t a i n i n g only small q u a n t i t i e s of i c e , most of the pore space i s f i l l e d w i t h a i r (Tedrow and H i l l , 1955). 118 (a) A r c t i c Brown normal phase (Tedrow et a l . , 1958) (Figure 29) Occurring only i n a l p i n e and a r c t i c regions on moderately to w e l l drained slopes. S o i l s are loose w i t h r e s t r i c t e d c l a y formation and visually have a r i c h p r e c i p i t a t i o n of f r e e f e r r i c hydroxides. The s o i l has a high water p e r m e a b i l i t y but owing to i n s u f f i c i e n t , r a i n f a l l and absence of humus s o i l formation, p o d z o l i z a t i o n does not occur. S o i l s i n t h i s category are c h a r a c t e r i s t i c of the ' c l i m a t i c climax' V a c c i n i o - Betuletum glandulosae i n t h i s r e g ion o f the low a r c t i c Subalpine Zone. The a s s o c i a t i o n i s present on the mid to upper slopes as w e l l as i i i ex-posed areas along lake shores. On the upper slopes i t i s present i n s h e l t e r e d depressions. Sampled p l o t s v a r i e d i n e l e v a t i o n from 1100-1900 f t . A l l s i t e s are moderately w e l l drained and have a snow f r e e p e r i o d of 10-12 weeks. The u n d u l a t i n g m i c r o r e l i e f i s i n d i c a t i v e of f r o s t a c t i o n , and downslope movement ( s o l i f l u c t i o n ) occurs i n h a b i t a t s on the steeper slopes. Unconsolidated parent m a t e r i a l i s always c l o s e to the surface and small fragments are present through-out the p r o f i l e . P h y s i c a l and chemical weathering are probably e q u a l l y important (there i s no a c t u a l experimental evidence to support t h i s h y p o t h e s i s ) . In more temperate r e t i o n s l a c k i n g p e r e n n i a l l y frozen ground heavy s o i l s are p r a c t i c a l l y n on-existent. In t h i s area of continuous permafrost c l a y (hand t e x t u r e determination) horizons are d i s c e r n i b l e i n the t e r r e s t r i a l s o i l s . How-ever, these are probably s i l i c a t e c l a y s that are d e r i v e d from comparative s l i g h t p h y s i c a l and chemical a l t e r a t i o n of the primary m i n e r a l s . P r o f i l e s are g e n e r a l l y shallow w i t h d i s t i n c t l y developed, f r e q u e n t l y humus r i c h dark-brown to b l a c k i s h A h o r i z o n s . The (B) h o r i z o n i s u s u a l l y l i g h t e r i n colour and h e a v i e r w i t h combinations of clay-loam or sandy-loam grading i n t o a ' s i l i c a t e ' c l a y that o v e r l i e s the parent m a t e r i a l . Percent organic matter i s high i n the surface horizons and decreases r a p i d -l y with depth. Cation exchange c a p a c i t y i s h i g h , while base s a t u r a t i o n i s g e n e r a l l y low. Exchangeable c a t i o n s , dominated by calcium, are present i n 119 moderate amounts. Magnesium values are higher i n the organic l a y e r of the V a c c i n i o - Betuletum glandulosae than i n any other a s s o c i a t i o n . S o i l pH i s moderately to s t r o n g l y a c i d and shows l i t t l e v a r i a t i o n with depth. The s o i l edaphotope i s considered to be permesotrophic. Figure 29. A r c t i c Brown s o i l normal phase (Tedrow et a l . , 195S) a s s o c i a t e d with the V a c c i n i o - Betuletum glandulosae betuletosum glandulosae ( f r u t i c u l o s u m ) . S o i l p r o f i l e taken through hummock. The A h o r i z o n i s not c l e a r l y d i s t i n g u i s h a b l e , however, the B h o r i z o n i s w e l l developed and l i g h t i n colou r . (Photo by K r a j i n a ) 120 M o r p h o l o g i c a l l y these p r o f i l e s i n d i c a t e a degree of decomposition and h u m i f i c a t i o n i n the upper p o r t i o n of the surface horizons. M i c r o s t r u c t u r e c o n s i s t s p r i n c i p a l l y of l o o s e l y arranged, p h y s i c a l l y weathered mineral g r a i n s . A l s o included i n the A r c t i c Brown normal phase s o i l type i s the Betulo -Ledetum decumbentis b e t u l o - ledetum decumbentis. This a s s o c i a t i o n i s present on the upper slopes i n more, exposed p o s i t i o n s . S o i l p r o f i l e s are shallower than those of the V a c c i n i o - Betuletum glandulosae, between 19-33 cm i n depth over packed unconsolidated sandstone felsenmeer. The p r o f i l e s i n d i c a t e greater s t a b i l i t y r e l a t i v e to f r o s t displacement by the c o n t i n u i t y of p r o f i l e morphol-ogies. Colour changes are d i s t i n c t i v e and range from dark brown to reddish and h i g h l y organic i n the upper h o r i z o n , grading to grey-brown sandy loam to yellow s i l t y - c l a y . Because of the coarse t e x t u r e , a e r a t i o n i s much improved and the s i t e s are considered w e l l drained. Percent organic matter i s high i n the surface h o r i z o n and drops r a p i d l y with depth. Exchangeable cations are low and the c a t i o n exchange c a p a c i t y i s high. The i n d i c a t i o n that the exchange complex i s satu r a t e d w i t h hydrogen (H+) i s r e f l e c t e d i n the s t r o n g l y a c i d sur-face horizons (3.7 to 4.3). P e r e n n i a l l y frozen organic-mineral s o i l was never found because of the c l o s e p r o x i m i t y to the surface of felsenmeer. P r o f i l e morphology i n the Betulo - Ledetum decumbentis cassiopeetosum tetragonae i s more c l o s e l y a l i g n e d to the A r c t i c Brown normal phase, however, as has been pointed out, there are s e v e r a l p r o f i l e s that because of t h e i r more d i s t u r b e d nature are considered as A r c t i c R a n k e r - l i k e . The major d i f f e r e n c e i n the cassiopeetosum tetragonae i s the longer snow cover. S c a t t e r e d accumu-l a t i o n s o f l i t t e r are present and packed down by snow i n depressions. Chemical analyses of the major base n u t r i e n t s , c a t i o n exchange c a p a c i t y and s o i l pH i n d i c a t e a c l o s e a s s o c i a t i o n with the Betulo - Ledetum decumbentis bet u l o -ledetum decumbentis. A l l s o i l edaphotopes i n the A r c t i c Brown normal phase are considered to be mesotrophic. 121 S o i l - V e g e t a t i o n R e l a t i o n s h i p s In summarizing the r e l a t i o n s h i p s between s o i l and vegetation i n the Low-A r c t i c Subalpine Zone the. process of c o n g e l i t u r b a t i o n must be considered to pl a y a major r o l e i n both s o i l p r o f i l e development and p l a n t species d i s t r i -b u t i o n . I n t i m a t e l y r e l a t e d to t h i s process i s the development of patterned ground. The major forms of patterned ground i n the A r c t i c have been s t u d i e d and described by geomorphologists (Washburn, 1956). Several s o i l s c i e n t i s t s (Drew, 1957 and Brown, 1962) have attempted, w i t h some success, to r e l a t e cer-t a i n forms of patterned ground to genetic s o i l s . B o t a n i s t s have a l s o made se v e r a l important c o n t r i b u t i o n s i n the f i e l d of ecology (Tedrow, 1963). In a d d i t i o n to the p h y s i c a l processes o c c u r r i n g i n the s o i l , moisture changes brought about by changes i n m i c r o r e i i e f a l s o have an i n f l u e n c e on p l a n t d i s t r i b u t i o n . A l t e r a t i o n s of a s i t e produce changes i n drainage and other p h y s i c a l c h a r a c t e r i s t i c s , and some pedologic processes a l t e r s o i l morphology very slowly toward the new c o n d i t i o n , the b i o t a i s f r e q u e n t l y a l t e r e d dras-t i c a l l y from the edaphic c o n d i t i o n s under which the s o i l morphology developed (Tedrow, 1963). This c o n d i t i o n i s perhaps best i l l u s t r a t e d i n the transformation from low-centered polygons to high-centered polygons. Ridges increase i n height and number as a r e s u l t of developing i c e wedges. The more elevated areas o f the ridges are b e t t e r drained and t h i s i s r e f l e c t e d i n an i n c r e a s e i n the abundance of more mesic v e g e t a t i o n dominated by dwarf shrub and ericaceous spe-c i e s . The depressions, on the other hand, remain dominated by more sub-aquatic v e g e t a t i o n . This change i n species i s r e l a t e d to a r e d u c t i o n i n s o i l moisture due to improved drainage within, the r i d g e or hummock. I t may be i m p l i e d from the v e g e t a t i o n and s o i l analyses presented here, that there i s a c o r r e l a t i o n between the s e m i - t e r r e s t r i a l (chionophilous) and t e r -r e s t r i a l s o i l s and t h e i r v e g e t a t i o n (Table 16). Because of t h i s c o r r e l a t i o n , at l e a s t i n the two study areas, one should be able to describe the s o i l type 122 by the p l a n t a s s o c i a t i o n of the h a b i t a t . In the wetlands, excluding the chionophilous h a b i t a t s , i t . would be d i f f i c u l t to p o s i t i v e l y c o r r e l a t e both s o i l and v e g e t a t i o n . While t h i s has been t e n t a t i v e l y o u t l i n e d i t . must be remembered that both the Eriophoretum scheuchzeri and Caricetum r a r i f l o r a e are underrepresented and considered to be i n a s t a t e of f l u x due to excessive f r o s t heaving. No s o i l p r o f i l e s were described f o r the low-centered polygon r i d g e s . However, s e v e r a l s e c t i o n s were made through r i d g e s to observe pro-f i l e morphology. In a l l cases, except f o r the upper few centimeters, the pro-f i l e c o n s i s t e d of undecomposed Sphagnum s i m i l a r to t h a t found i n the depressions. .123 DESCRIPTION OF HIGHER UNITS OF CLASS1FICATION - ALLIANCES AND ORDERS Follo w i n g the a n a l y s i s and d e s c r i p t i o n of the major p l a n t a s s o c i a t i o n s i n the two study areas u n i t s of higher rank were determined using c h a r a c t e r i s t i c species combinations (Table 18). A t o t a l of 6 Orders and 9 A l l i a n c e s were recognized. Many of the higher u n i t s bear a c l o s e r e l a t i o n s h i p t o u n i t s of s i m i l a r rank i n Europe (Braun-Blanquet, 1932, K r a j i n a , 1933, Nordhagen, 1943 and Dahl, 1956). The B e t u l e t a l i a glandulosae i s the dominant order i n the two study areas where i t i s g e n e r a l l y present at higher e l e v a t i o n s on x e r i c to mesic s o i l s that, are moderately to s l i g h t l y a c i d . The order i s c h a r a c t e r i z e d by dwarf shrub s p e c i e s , u s u a l l y l e s s than 2 1/2 f t h i g h , with high cover and constancy values. In the more x e r i c s i t e s l i c h e n coverage exceeds that, of the bryophytes whereas i n the more mes:ic s i t e s the revei'se i s the case. Two a l l i a n c e s are recognized. The Betulo - Dryadion * a l a s k e n s i s on x e r i c , moderately to s l i g h t l y a c i d s o i l s , and the B e t u l i o n glandulosae on s u b - x e r i c to mesic, moderately a c i d s o i l s . The l a t t e r i s the major a l l i a n c e w i t h V a c c i n i o - Betuletum glandulosae considered to represent the c l i m a t i c climax f o r t h i s area of the Low A r c t i c Subalpine Zone. A l l hummock dominated communities i n the semi-hydric to h y g r i c h a b i t a t s belong to the order Sphagnetalia. Communities are dominated by hummock-building Eriophorum vaginatum, Sphagnum s p e c i e s , dwarf shrubs or ericaceous v a s c u l a r p l a n t s . The s o i l s are s t r o n g l y to moderately a c i d . The order i s second i n importance a f t e r the B e t u l e t a l i a glandulosae and i s r e s t r i c t e d i n the m a j o r i t y of cases to the lower slope's. In Alaska the Sphagnetalia or Eriophorum  vaginatum dominated s i t e s are considered to dominate l a r g e r areas than any other v e g e t a t i o n type (Hanson, 1953, C h u r c h i l l , 1955, P o r s i l d , 1951 and Spetzman, 1959). In Europe the Sphagnetalia show some a f f i n i t y to the 1. The f o l l o w i n g d e s c r i p t i o n of higher u n i t s of c l a s s i f i c a t i o n were derived w i t h the a s s i s t a n c e of Dr. V. J . K r a j i n a . Table 18 C l a s s i f i c a t i o n of p l a n t communities of the Low A r c t i c Subalpine Zone on the b a s i s of c h a r a c t e r i s t i c species combinations. ZONE: Subalpine/Low Arctic (Betula glandulosa) characteristic species combination S.p. L. - D.a. B. - L-d. V. - B. g. B .-C. B.-E.v. S.pul. S.c. S.ps. C r . E.s. C.a. E.a. A. f . Betula glandulosa 1 III 1.3(+-5) V 4.6(1-7) V 5 5(2-9) V 5.8(4-8) V 3.1(1-5) III 1.6(1-4) I -2(+-1) IV 2.7(3-5) II 2.5(3-7) II •2(2-3) III •9(1-3) Sal ix pulchra II .7(1-4) IV 2 5(1-7) IV 3.4(3-6) III 1.6(1-5) V 8.4(7-9) III 1.3(1-8) II •5(1-4) II 2.0(2-8) Sal ix glauca II 1.0(1-6) I •2(1-2) III 1 1(1-5) II .8(1-5) I .2(1-2) H Alnus crispa H II 2.8(7) 1 Empetrum hermaphroditum IV 2.3(1-6) III 1 3(1-6) V 4-5(2-8) V 1.8(1-4) II -3(+-2) I -1(1) IV 1.7(2-3) Ledum decumbens 1 » V 3.6(1-6) V 2 3(1-6) V 4.0(2-6) V 3.0(+-5) I .4(1-4) , « I .1(+-1) III •5(1) Spiraea beauverdiana II .4(1-2) III 1.8(1-5) n II 1.6(2-7) II 1.7(1-6) Vaccinium uliginosum IV 2.4(1-7) V 2.5(1-6) V 4 0(1-7) V 4.4(3-6) V 2.1(1-3) III 1.4(1-7) II -3 ( + -2 ) IV 1.0(+-2) H I •3(1-4) II •7(+-3) Vaccinium vitis-Idaea » I •2(1-2) V 3.5(1-6) v 2 3(1-6) V 3.3(1-6) V 4.1(1-5) II •7(+-2) II -4(1-3) H II •3<*-1) Poa arct ic 1 III 1.0(+-3) III •5(+-3) III 9(+-3) II .8(+-3) II • 4(+-3) IV 1.2(+-3) IV 1.6(1-4) IV .2(1-2) Artemisia arct ica II .4(1) II •5(+-2) I .2(1-2) I 2(1) II •8(+-6) r v 3.0(+-7) III 1.6(1-5) Polygonum bistorts ssp.plumosum II • 3(+-D IV 1.1(+-4) IV 1 3(+-3> IV 1.2(1-3) III .8(1-2) i n • 9(+-3) III -0(+-2) Arctagrostis l a t i f o l i a II .6(1-4) II • 5(+-3) III 1 2(+-3) IV 1.3(1-3) 1 .5(+-2) r v 2.1(1-6) V 2.8(1-8) Eriophorum vaginatum H I 1 0(3-6) III .7(1-2) V 7.0(5-8) I