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Environmental factors limiting success of revegetation on man-made waterfowl nesting islands in east-central… Fehr, Alan William 1989

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ENVIRONMENTAL FACTORS LIMITING SUCCESS OF REVEGETATION ON MAN-MADE WATERFOWL NESTING ISLANDS IN EAST-CENTRAL ALBERTA by ALAN WILLIAM FEHR B. Sc., The University of Alberta, 1981 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES Department of Plant Science We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA July 1989 © ALAN W. FEHR, 1989 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of P(o\ W~t ScjCt* c € The University of British Columbia Vancouver, Canada DE-6 (2788) DEDICATED TO THE MEMORY OF ALEXANDER (ALEC) JOHN JOSEPH RITTER August 9, 1951 - December 8, 1986 A GOOD FRIEND AND DEDICATED BIOLOGIST ABSTRACT Vegetation and environment r e l a t i o n s h i p s were i n v e s t i g a t e d on man-made ear t h i s l a n d s i n J u l y and August of 1985 and 1986. The i s l a n d s were b u i l t by Ducks U n l i m i t e d Canada to provide upland n e s t i n g cover f o r waterfowl. Twenty i s l a n d s d i s t r i b u t e d throughout 12 wetlands (sloughs) were s t u d i e d . The wetlands are l o c a t e d i n e a s t - c e n t r a l A l b e r t a i n the aspen parkland ecoregion. The f l o r a and s o i l s of each i s l a n d were described. C o r r e l a t i o n a n a l y s i s was used to r e l a t e t o t a l and i n d i v i d u a l species f o l i a r cover to environmental, p r i m a r i l y s o i l , v a r i a b l e s . A p o i n t - i n t e r c e p t frame and a nestingboard were used to record f o l i a r cover i n l-m^ quadrats. S o i l s (0 - 15 cm depth) were c o l l e c t e d w i t h i n the quadrats. At l e a s t 3 q u a d r a t s / i s l a n d were sampled. The quadrats were p o s i t i o n e d on the i s l a n d s using a s t r a t i f i e d - r a n d o m framework. The f o l l o w i n g s o i l p r o p e r t i e s were measured: t o t a l N (N) , pH, e l e c t r i c a l c o n d u c t i v i t y , exchangeable and s o l u b l e c a t i o n s , sodium adsorption r a t i o (SAR), exchangeable sodium percentage (ESP), c a t i o n exchange c a p a c i t y (CEC), phosphorus (P) , organic carbon (C) , bulk d e n s i t y (BD), steady-state i n f i l t r a t i o n and p o r o s i t y . The f o l l o w i n g s i t e v a r i a b l e s were measured: slope, aspect, microtopography, quadrat height-above-water, effervescence, and macrotopography ( p o s i t i o n on i s l a n d ) . The i s l a n d f l o r a i n c l u d e d 59 v a s c u l a r species on 20 i s l a n d s i n 1985. In 1986, 40 species were recorded on 11 i s l a n d s . Sow t h i s t l e (Sonchus ulignosus) and t a l l wheatgrass {Agropyron elongatum) were the most frequent species i n 1985 and 1986, r e s p e c t i v e l y . Yellow sweet c l o v e r (Melilotus officinalis) and t a l l wheatgrass had the gre a t e s t mean f o l i a r cover i n those years. T a l l wheatgrass and yellow sweet c l o v e r were the most s u c c e s s f u l seeded species i n terms of f o l i a r cover and frequency; sow t h i s t l e , Canada t h i s t l e (Cirsium arvensis), and f o x t a i l b a r l e y (Hordeum jubatum) were the most s u c c e s s f u l nonseeded spec i e s . Seeded species coverage averaged 20%, compared t o 30% f o r nonseeded speci e s . I s l a n d f o l i a r cover was approximately 50% i n 1985 and 1986, ranging from 14% at Kingston Slough to 89% at Louis Lake i n 1985 and from 16% at R o l l y v i e w Marsh to 84% at Louis Lake i n 1986. I s l a n d s o i l s f i t a continuum ranging from non-sodic and non-saline, w i t h low bulk d e n s i t y f o sodic or s a l i n e - s o d i c , w i t h high bulk d e n s i t y . E l e c t r i c a l - c o n d u c t i v i t y of the i s l a n d s averaged 2.5 dS/m, bulk d e n s i t y averaged 1100 kg/m-*, and pH ranged from 6.2 t o 9.5. T o t a l p o r o s i t y and a e r a t i o n p o r o s i t y averaged .59.2% and 11.1%, r e s p e c t i v e l y . SAR averaged 12.9. i v F o l i a r cover was not related to i s l a n d age or the - time since seeding; nor was i t related to the available weather v a r i a b l e s . In general, i s l a n d f o l i a r cover was correlated with a l k a l i n i t y , s o d i c i t y and bulk density. Seven variables were correlated with t o t a l f o l i a r cover (point-intercept frame method) i n 1985 and 1986: bulk density (-) , exchangeable Na (-) , pH (-) , organic carbon ( + ) , t o t a l N (+), and exchangeable Ca and Mg (+). Stepwise multiple c o r r e l a t i o n i d e n t i f i e d pH (-) , exchangeable Na (-), and bulk density (-) as having the best re l a t i o n s h i p with f o l i a r cover i n 1985 (r^ = 0.64). The only difference i n 1986 was the addition of e l e c t r i c a l conductivity to the re l a t i o n s h i p (r^ = 0.56). The relationships between nestingboard f o l i a r cover and the environment were sim i l a r to those between t o t a l f o l i a r cover and the environment. A l k a l i n i t y , s o d i c i t y and bulk density also exerted a strong influence on the coverage of i n d i v i d u a l species. Half of the dominant species were correlated (+ or -) with pH, and 30% were correlated with bulk density and exchangeable Na. Recommendations for establishing vegetation on man-made earth islands are provided. v TABLE OF CONTENTS Page DEDICATION. . i i ABSTRACT i i i LIST OF TABLES . . i x LIST OF FIGURES x i i LIST OF APPENDICES x i i i ACKNOWLEDGEMENTS x i v 1. INTRODUCTION 1 2 . LITERATURE REVIEW 4 A. WATERFOWL HABITAT. . . 4 B. VEGETATION AND SOIL RELATIONSHIPS 8 3. HYPOTHESES 12 4 . STUDY AREA 13 A. LOCATION 13 B. CLIMATE.. • 15 C. SOILS.. 17 D. TOPOGRAPHY AND GEOLOGY 2 0 E. DRAINAGE 22 F. HISTORY AND LAND USE 22 G. VEGETATION..... 24 H. . WILDLIFE 2 9 I. DUCKS UNLIMITED CANADA PROJECTS 30 v i 5. METHODS 33 A. WETLAND AND ISLAND SELECTION....... 33 B. SAMPLING METHODS 34 C. SOIL ANALYSIS 38 D. DATA ANALYSIS 40 6. RESULTS .....43 A. FLORA 43 B. TOTAL FOLIAR, NESTINGBOARD, LITTER AND SOIL COVER FOR EACH WETLAND 47 C. ISLAND SOIL AND SITE CONDITIONS... 50 S o i l Chemical Conditions 50 S o i l P h y s i c a l Conditions 59 S i t e C h a r a c t e r i s t i c s 62 D. IMPACT OF WEATHER AND ISLAND AGE ON PLANT COVER 63 E. IMPACT OF SOIL AND SITE CONDITIONS ON TOTAL FOLIAR COVER 63 Simple L i n e a r C o r r e l a t i o n 63 M u l t i p l e L i n e a r C o r r e l a t i o n ...65 F. SEEDED AND NONSEEDED FOLIAR COVER. 68 Simple. L i n e a r C o r r e l a t i o n 68 M u l t i p l e L i n e a r C o r r e l a t i o n . 69 G. GRAMINOID AND FORB FOLIAR COVER 71 Simple Li n e a r C o r r e l a t i o n 71 M u l t i p l e L i n e a r C o r r e l a t i o n 72 H. INDIVIDUAL SPECIES FOLIAR COVER 74 A l f a l f a 74 Canada T h i s t l e . 74 Crested Wheatgrass ...75 F o x t a i l Barley 76 Intermediate Wheatgrass 77 Creeping Red Fescue 78 S a l t Meadow Grass 79 Sedge Species 80 Smooth Brome Grass.. 81 Sow T h i s t l e 82 v i i T a l l Wheatgrass 83 Whitetop Grass..: 84 Yellow Sweet Clover 85 7. DISCUSSION 87 A. ISLAND FLORA 87 B. ISLAND SOIL AND SITE CONDITIONS 90 C. TOTAL FOLIAR COVER 98 Nestingboard Method .118 D. OTHER MEASURES OF FOLIAR COVER 121 E. INDIVIDUAL SPECIES COVER 125 F. WEATHER EFFECTS ON FOLIAR COVER ..145 G. DISCUSSION OF METHODS 147 H. SOIL VARIABILITY. 151 8. SUMMARY OF RESULTS ...154 9. CONCLUSIONS AND MANAGEMENT RECOMMENDATIONS 157 10. LITERATURE CITED 168 11. PERSONAL COMMUNICATIONS 178 v i i i LIST OF TABLES Page 4.1 Locations of study wetlands 13 4.2 Climatic averages for the Stettler, Hughenden, and Camrose, Alberta meteorological stations, 1951 - 1980 (Atmospheric Environment Service 1982) 16 4.3 Precipitation and temperature for Camrose, Alberta, 1985 and 198 6 (Atmospheric Environment Service 1982) 17 5.1 Distribution of samples among islands and wetlands 3 6 5.2 Microtopography categories used at each quadrat...37 5.3 Methods and references of chemical and physical analyses performed on s o i l samples .....39 6.1 Frequency of plant species recorded within quadrats in 1985 and 1986 44 6.2 Foliar cover (%) for plant species recorded with the point-intercept method in 198.5 and 1986. 45 6.3 Species dominant and subdominant, in terms of f o l i a r cover, on wetland islands in 1985 and 1986 46 6.4 Mean fo l i a r cover (%), measured with the point-intercept method, in 1985 and 1986. Nestingboard values (%) are bracketed 48 6.5 Mean fo l i a r cover (%) of seeded and nonseeded (in brackets) vegetation in 1985 and 1986 49 6.6 Mean (%) and range (%) of l i t t e r , s o i l and bryophyte cover at each wetland in 198 6 50 6.7 Electrical conductivity (dS/m) of island soils in 1985 and 1986 .51 6.8 Exchangeable (cmol/kg) and soluble (me/L) cation levels of island soils in 1985 and 1986....52 ix 6.9 Mean sodium adsorption r a t i o s (SAR), exchangeable sodium percentage (ESP), c a t i o n exchange c a p a c i t y (CEC), and phosphorus l e v e l s of i s l a n d s o i l s . SAR, ESP, and CEC were measured i n 198 6, whereas P was measured i n 1985. . 56 6.10 S o i l pH, organic carbon (%), and t o t a l . n i t r o g e n (%) l e v e l s averaged by i s l a n d and year. 58 6.11 Mean bulk d e n s i t y (kg/m^) f o r i s l a n d s sampled i n 1985 and 1986 59 6.12 T o t a l p o r o s i t y and a e r a t i o n p o r o s i t y , expressed as a percentage of the t o t a l volume, and percent c l a y of i s l a n d s o i l s . P o r o s i t y was measured i n 1986, whereas c l a y was measured i n 1985 60 6.13 Average steady-state i n f i l t r a t i o n r a t e s (cm/h) f o r 1985 and 1986... 61 6.14 S o i l and s i t e v a r i a b l e s c o r r e l a t e d w i t h t o t a l f o l i a r and nestingboard cover (P < 0.05) 64 6.15 M u l t i p l e c o r r e l a t i o n analyses of t o t a l f o l i a r and nestingboard cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05)......... 67 6.16 S o i l and s i t e v a r i a b l e s c o r r e l a t e d (P < 0.05) w i t h seeded and nonseeded species f o l i a r cover....69 6.17 M u l t i p l e c o r r e l a t i o n analyses of seeded and nonseeded species f o l i a r cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05)...... 70 6.18 S o i l and s i t e v a r i a b l e s c o r r e l a t e d (P < 0.05) w i t h forb and graminoid species f o l i a r cover 71 6.19 M u l t i p l e c o r r e l a t i o n analyses of f o r b and graminoid species f o l i a r cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05)... 73 6.20 Simple and m u l t i p l e c o r r e l a t i o n analyses of Canada t h i s t l e f o l i a r cover w i t h environmental v a r i a b l e s (P < 0.05) 75 6.21 Simple and m u l t i p l e c o r r e l a t i o n analyses of c r e s t e d wheatgrass f o l i a r cover w i t h environmental v a r i a b l e s (P < 0.05) 76 x 6.22 Simple and m u l t i p l e c o r r e l a t i o n analyses of f o x t a i l b a r l e y f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 77 6.23 Simple and m u l t i p l e c o r r e l a t i o n analyses of intermediate wheatgrass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 78 6.24 Simple and m u l t i p l e c o r r e l a t i o n analyses of creeping red fescue f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 79 6.25 Simple and m u l t i p l e c o r r e l a t i o n analyses of • s a l t meadow grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 80 6.26 Simple and m u l t i p l e c o r r e l a t i o n analyses of sedge f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 81 6.27 Simple and m u l t i p l e c o r r e l a t i o n analyses of smooth brome grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 82 6.28 Simple and m u l t i p l e c o r r e l a t i o n analyses of sow t h i s t l e f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 83 6.29 Simple and m u l t i p l e c o r r e l a t i o n analyses of t a l l wheatgrass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 84 6.30 Simple and m u l t i p l e c o r r e l a t i o n analyses of whitetop grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 85 6.31 Simple and m u l t i p l e c o r r e l a t i o n analyses of yellow sweet c l o v e r f o l i a r cover and environmental v a r i a b l e s (P < 0.05) 8 6 x i L I S T OF FIGURES Page 1. L o c a t i o n of study wetlands i n the c e n t r a l aspen parkland ecoregion (outlined) of A l b e r t a 14 2. A e r i a l view of a Ducks U n l i m i t e d wetland set i n n a t i v e aspen parkland . 25 3. A e r i a l photograph, taken i n May 1980, of t y p i c a l man-made ea r t h i s l a n d s i n S i s i b Lake 26 4. Photograph of a sodi c , a l k a l i n e i s l a n d i n Kingston Slough (July 1986) 32 5. Photograph of sodic Hebert Lake i s l a n d 104 6. Yellow sweet c l o v e r on Z i l k e Marsh i s l a n d 127 7. Photograph of the dense, nonseeded v e g e t a t i o n on Louis Lake i s l a n d , August 1986 142 x i i LIST OF APPENDICES Page 1. I s l a n d seeding h i s t o r i e s and sketches of the wetlands showing study i s l a n d s 179 2. Species recorded i n quadrats on i s l a n d s i n 1985 and 1986. . 186 3. Percent f o l i a r cover (not bracketed) and frequency ( i n brackets) of i n d i v i d u a l species on each i s l a n d and o v e r a l l , i n 1985 and 1986 189 x i i i ACKNOWLEDGEMENTS I f i r s t wish to thank my supervisor, Dr. Michael P i t t , for his advice, support and guidance throughout the research. Thanks also go to Gary Stewart and Kim Schmitt, both with Ducks Unlimited, for their valuable cooperation and support. Dennis Pfeffer and Blaine Burns provided valuable assistance in the f i e l d . Final thanks go to my wife, Marilyn, who assisted, encouraged and constructively pestered me to f i n i s h . This research was funded by a NSERC postgraduate scholarship and a grant from the Alberta Environmental Research Trust. Ducks Unlimited Canada provided both financial and logistic support. xiv 1. INTRODUCTION U p l a n d w i l d l i f e h a b i t a t i s d e c l i n i n g t h r o u g h o u t t h e C a n a d i a n p r a i r i e s c o n c u r r e n t w i t h a g r i c u l t u r a l a n d u r b a n l a n d e x p a n s i o n . W i l d l i f e a g e n c i e s , s u c h a s D u c k s U n l i m i t e d C a n a d a ( D U ) , c o n s t r u c t e a r t h i s l a n d s f r o m d r e d g e d l a k e s e d i m e n t t o h e l p o f f s e t t h e l o s s o f w a t e r f o w l n e s t i n g h a b i t a t . F o l l o w i n g c o n s t r u c t i o n , r a p i d e s t a b l i s h m e n t o f i s l a n d v e g e t a t i o n i s d e s i r e d , n o t o n l y t o p r o v i d e n e s t i n g c o v e r , b u t a l s o t o m i n i m i z e s o i l e r o s i o n a n d t o m a x i m i z e i s l a n d l o n g e v i t y . E s t a b l i s h i n g v e g e t a t i o n , h o w e v e r , i s o f t e n d i f f i c u l t b e c a u s e o f u n f a v o u r a b l e s i t e c o n d i t i o n s , s u c h a s h i g h s a l t c o n c e n t r a t i o n s , p o o r s o i l s t r u c t u r e , a n d d r y m o i s t u r e r e g i m e s . I m p r o v i n g e s t a b l i s h m e n t w o u l d i n c r e a s e w a t e r f o w l p r o d u c t i v i t y a n d , f r o m D U ' s p e r s p e c t i v e , i m p r o v e t h e r e t u r n o n t h e i r i n v e s t m e n t . T h e f o l l o w i n g m a t h e m a t i c a l m o d e l p r o v i d e s t h e b a s i s f o r t h e s t u d y o f v e g e t a t i o n i n g e n e r a l , a n d i s l a n d v e g e t a t i o n , s o i l s a n d s i t e , i n p a r t i c u l a r : v e g e t a t i o n = f ( t i m e + p r e d i c t o r v a r i a b l e s + r e s i d u a l ) , w h e r e t h e p r e d i c t o r v a r i a b l e s i n c l u d e f a c t o r s s u c h a s c l i m a t e , s o i l , s i t e , . b i o t a , h u m a n a c t i o n s , a n d p l a n t d i s p e r s a l ( O l s o n 1 9 5 8 ) . V a r i a b l e s t h a t i n f l u e n c e v e g e t a t i o n , b u t c a n n o t b e m e a s u r e d o r c o n t r o l l e d , a r e p a r t o f t h e r e s i d u a l t e r m . P l a n t e c o l o g y s t u d i e s w h i c h a d d r e s s e n v i r o n m e n t a n d v e g e t a t i o n r e l a t i o n s h i p s a r e c o m m o n . U s u a l l y a n a t t e m p t i s m a d e t o v e r i f y t h e e x i s t e n c e o f a p l a n t c o m m u n i t y b y 1 i d e n t i f y i n g and d e l i n e a t i n g i t i n terms of s o i l and s i t e c o n d i t i o n s ( G r i g a l and Arneman 1970; Dix and Swan 1971; Munn et a l . 1978; Hutchinson 1980; Y a r i e 1983; B r a d f i e l d and Campbell 1986; Gagnon and B r a d f i e l d 1986; P a r a t l e y and Fahey 1986) . Most p l a n t succession s t u d i e s concentrate on the change i n v e g e t a t i o n as a f u n c t i o n s o l e l y of time (Drury and Nisbet 1973) . Although v e g e t a t i o n development on an i s l a n d i s an example of primary succession (the lake sediment from which the i s l a n d s are b u i l t has never been vegetated), s u c c e s s i o n a l s t u d i e s u s u a l l y cover v e g e t a t i o n sequences spanning s e v e r a l hundred years, or the l i f e of - a p l a n t community. On the study i s l a n d s , time as a v a r i a b l e i s not important because r a p i d establishment (< 5 years) i s important f o r i s l a n d l o n g e v i t y . S o i l and s i t e v a r i a b l e s , some of which can be manipulated, are of primary i n t e r e s t . Rapid v e g e t a t i o n establishment enhances waterfowl p r o d u c t i v i t y d i r e c t l y by p r o v i d i n g n e s t i n g cover. A d d i t i o n a l l y , decreased water e r o s i o n and s i t e degradation improve i s l a n d p e r s i s t e n c e and p l a n t cover. E a r t h i s l a n d s are w e l l s u i t e d f o r v e g e t a t i o n s t u d i e s . They have a r e l a t i v e l y depauperate f l o r a because d i s p e r s a l to i s l a n d s i s l i m i t e d and because slough-bottom sediment, of which the i s l a n d s are constructed, probably has a small seed-bank. Low species d i v e r s i t y s i m p l i f i e s data a n a l y s i s . This study e s t a b l i s h e s the r e l a t i o n s h i p s between p l a n t f o l i a r cover on n e s t i n g i s l a n d s w i t h . s o i l and s i t e 2 conditions. In addition, the importance of native, or nonseeded, species in vegetation establishment w i l l be studied. The study has five objectives: 1) describe the island flora and soils.; 2) determine the role physical and chemical s o i l factors play in vegetation establishment; 3) determine the role site factors play in vegetation establishment; 4) assess the success and dominance of nonseeded and seeded species in relation to s o i l factors; and 5) provide' recommendations for. establishing vegetation on islands. 3 2. LITERATURE REVIEW A. WATERFOWL HABITAT A g r i c u l t u r a l and urban settlement of the Canadian P r a i r i e s and aspen parkland began i n the l a t e 1800s. Upland w i l d l i f e h a b i t a t has s t e a d i l y d e c l i n e d as c u l t i v a t e d and urban lands expand (Sugden and Beyersbergen 1984) . North (1976) estimated t h a t 90 - 95% of the aspen parklan d has been a l t e r e d or destroyed. To overcome the l o s s of waterfowl n e s t i n g h a b i t a t , s e v e r a l researchers have recommended the c o n s t r u c t i o n of e a r t h i s l a n d s (Hammond and Mann 1956; K e i t h 1961; Duebbert et a l . 1983). Giroux (1981a) and Johnson et a l . (1978) s t u d i e d waterfowl use of man-made ear t h i s l a n d s and concluded t h a t i s l a n d c o n s t r u c t i o n i s a p r a c t i c a l means of p r o v i d i n g n e s t i n g h a b i t a t . Hammond and Mann (1956) considered the f o l l o w i n g i s l a n d c h a r a c t e r i s t i c s to be important to waterfowl: 1) s e c u r i t y from predators r e l a t i v e to the mainland; 2) a l a r g e number of breeding t e r r i t o r i e s because of the high p r o p o r t i o n of s h o r e l i n e to landmass; and 3) the c l o s e p r o x i m i t y of food, water, l o a f i n g areas and nest cover. Man-made and n a t u r a l i s l a n d s are a t t r a c t i v e to waterfowl and c o n s i s t e n t l y show greater n e s t i n g success than the mainland (Keith 1961; Johnson et a l . 1978; Giroux 1981a; Hines and M i t c h e l l 1983; P i e s t and Sowls 1985). W i l d l i f e agencies, i n p a r t i c u l a r Ducks U n l i m i t e d Canada, now b u i l d e a r t h i s l a n d s to o f f s e t waterfowl h a b i t a t l o s s . Vegetation s u i t a b l e f o r n e s t i n g cover i s e s t a b l i s h e d 4 soon a f t e r i s l a n d c o n s t r u c t i o n . I s l a n d v e g e t a t i o n provides concealment and nest m a t e r i a l f o r ducks, geese, and other n e s t i n g b i r d s . Good concealment minimizes p r e d a t i o n and i n t e r s p e c i f i c harassment, and t h e r e f o r e improves n e s t i n g success (K e i t h 1961; Dwernychuk 1972; Ewaschuk and Boag 1972; Duebbert and Kantrud 1974; K i r s c h et a l . 1978; Giroux 1981a; Lokemoen et a l . 1984). The removal or disturbance of n e s t i n g cover through g r a z i n g , haying or c u l t i v a t i o n decreases nest success and d e n s i t y because of in c r e a s e d nest v i s i b i l i t y and predation ( K i r s c h 1969; Mundinger 1976; Higgins 1977; K i r s c h et a l . 1978). P r e d a t i o n has been c i t e d as a major cause of n e s t i n g f a i l u r e i n numerous s t u d i e s (Keith 1961; Duebbert and Kantrud 1974; O e t t i n g and Dixon 1975; Higgins 1977; Duebbert and Lokemoen 19.80; Duebbert et a l . 1983) . The type of vegetation p r e f e r r e d f o r n e s t i n g cover v a r i e s among waterfowl species and geographical l o c a t i o n s , but g e n e r a l l y waterfowl p r e f e r dense, moderately t a l l v e g e t a t i o n . On man-made and n a t u r a l i s l a n d s t h a t had high duck nest d e n s i t i e s and good nest success, p a r t i c u l a r l y of mallards (Anas platyrhyncos) and gadwalls (Anas strepera), the p r e f e r r e d n e s t i n g v e g e t a t i o n was e i t h e r 1) dense and weedy (e.g. n e t t l e (Urtica spp.), Canada t h i s t l e (Cirsium arvense), sow t h i s t l e (Sonchus spp.), lambs-quarter (Chenopodium album), and some grasses) (Hammond and Mann 1956; Duebbert 1966; Drewien and F r e d r i c k s o n 1970; Johnson et a l . 1978; Hines and M i t c h e l l 1983), or 2) composed of 5 dense patches of low shrubs (e.g. western snowberry (Symphoricarpos occidentalis) and common w i l d rose (Rosa woodsii)) (Duebbert et a l . 1983; Hines and M i t c h e l l 1983; Lokemoen et a l . 1984). Nest success i s p o s i t i v e l y c o r r e l a t e d w i t h v e g e t a t i o n height, canopy cover and concealment values (Dwernychuk 1972; Giroux 1981a; Hines and M i t c h e l l 1983). A v a r i e t y of vegetation types have been recommended f o r use i n e s t a b l i s h i n g n e s t i n g cover. Giroux (1981a) and Duncan (1986) recommended p l a n t i n g f o rb and grass, or forb mixtures. Duebbert and Kantrud (1974) and Duebbert and Lokemoen (1976) suggested forb and grass mixtures a l s o ; however, they recommended r e j u v e n a t i n g the stand every 5 to 10 years by burning or mowing. Hines and M i t c h e l l (1983) recommended snowberry or n e t t l e s or p l a n t s w i t h s i m i l a r physiognomy. Sugden and Beyersbergen (1986, 1987) recommended t a l l , dense cover, f o r example snowberry, as a p h y s i c a l b a r r i e r and behavioural d e t e r r e n t to crows.. Seeded, n a t i v e grasses were as a t t r a c t i v e to ducks as seeded, introduced grass and n a t i v e p r a i r i e ( K l e t t et a l . 1984). Ducks U n l i m i t e d s t u d i e d waterfowl use of t h e i r man-made i s l a n d s i n the p r a i r i e s and parkland i n the l a t e 1970s and e a r l y 1980s. Giroux (1981a,b) i d e n t i f i e d i s l a n d c h a r a c t e r i s t i c s that c o r r e l a t e d w i t h n e s t i n g use by water-f o w l . He found that ducks and geese p r e f e r grass and forb mixtures, and noted that i s l a n d seeding i n the Brooks, 6 A l b e r t a area was unsuccessful or e s t a b l i s h e d s l o w l y because of the dry moisture regime. Giroux (1981a) recommended a mixture of annual and p e r e n n i a l forb and grass species adapted to environmental c o n d i t i o n s encountered on i s l a n d s . Watering was suggested as a way of improving and a c c e l e r a t -i n g p l a n t establishment. Giroux (1981a,b) recommended making v e g e t a t i o n establishment an important process i n i s l a n d h a b i t a t development because of the p o s i t i v e i n f l u e n c e n e s t i n g cover has on i s l a n d use by waterfowl. Nelson (1985) reanalysed DU i s l a n d data c o l l e c t e d between 1979 and 1984 and found t h a t i s l a n d s w i t h good v e g e t a t i o n have more nests than those w i t h poor cover, although high nest success was not guaranteed. Studies by DU a l s o show th a t v e g e t a t i o n on man-made i s l a n d s decreases i s l a n d e r o s i o n . In 1984, e r o s i o n of i s l a n d s was assessed by a DU study committee ( I s l a n d E r o s i o n Study Committee 1984) . They concluded t h a t the a r e a l extent of v e g e t a t i v e cover on an i s l a n d i s a key f a c t o r i n f l u e n c i n g e r o s i o n , and tha t improving v e g e t a t i o n establishment would decrease e r o s i o n . Higgins (1986) found wave a c t i o n t o be the most damaging to the small man-made i s l a n d s he s t u d i e d . Hamm (1982) assessed the s o i l s of p r a i r i e and parkland man-made and n a t u r a l i s l a n d s i n Saskatchewan and concluded t h a t improved seeding p r a c t i c e s and p l a n t species s e l e c t i o n would improve the ve g e t a t i v e cover on the m a j o r i t y of i s l a n d s . 7 B. VEGETATION AND SOIL RELATIONSHIPS Studies of p l a n t and s o i l r e l a t i o n s h i p s are numerous. A g r i c u l t u r a l s t u d i e s emphasize the e f f e c t s s o i l charac-t e r i s t i c s have on p l a n t y i e l d ; reclamation s t u d i e s concen-t r a t e on stand establishment and p e r s i s t e n c e ; and p l a n t e c o l o g i s t s i d e n t i f y and d e l i n e a t e , or j u s t i f y , p l a n t community boundaries and g r a d i e n t s w i t h s o i l and s i t e v a r i a b l e s . Most a g r i c u l t u r a l s t u d i e s are experimental, whereas reclamation and p l a n t ecology s t u d i e s tend to i n v o l v e sampling and d e s c r i p t i o n , or c o r r e l a t i o n a n a l y s i s . D e s c r i p t i v e reclamation s t u d i e s g e n e r a l l y d e s c r i b e the c u r r e n t , and o c c a s i o n a l l y the previous s o i l c o n d i t i o n s and dominant s p e c i e s . No attempt i s made to s t a t i s t i c a l l y compare before and a f t e r c o n d i t i o n s , or t o r e l a t e s o i l s to v e g e t a t i o n (Moore and Zimmerman 1977; Crowder et a l . 1982; Sieg et a l . 1983). P l a n t - s o i l r e l a t i o n s h i p s t u d i e s of a more q u a n t i t a t i v e nature are a l s o common. In some cases, both p l a n t and s o i l are sampled q u a n t i t a t i v e l y , but then compared i n a q u a l i t a -t i v e or d e s c r i p t i v e manner (Hulett et a l . 1966; Dix and Swan 1971; Kotar 1986; M i l e s and Swanson 1986). Often the v e g e t a t i o n and s o i l components are measured at low or d i f f e r e n t l e v e l s of sample i n t e n s i t y and then compared, or the samples are composited and the composite used i n analyses ( G r i g a l and Arneman 1970; Dix and Swan 1971; Janz 1974; Jaynes and Harper 1978; Munn et a l . 1978; B u t l e r et a l . 1986; Kotar 1986). 8 M u l t i v a r i a t e a n a l y s i s of vegetation-environment data i s commonly used i n p l a n t ecology. In general, v e g e t a t i o n stands or communities are sampled and then summarized w i t h a m u l t i v a r i a t e method, such as p r i n c i p a l components or r e c i p r o c a l averaging analyses. The v e g e t a t i o n data are then c o r r e l a t e d or e x p l a i n e d i n terms of environment v a r i a b l e s (Yarie 1983; B r a d f i e l d and Scagel 1984; Brady 1984; Gagnon and B r a d f i e l d 1986; C a r t e r et a l . 1987; L i e f f e r s and L a r k i n -L i e f f e r s 1987). In these s t u d i e s v e g e t a t i o n tends to be sampled at a greater i n t e n s i t y than s o i l s . S o i l s and v e g e t a t i o n o c c a s i o n a l l y are sampled c o n c u r r e n t l y at the same l e v e l of i n t e n s i t y (Hutchinson 1980; Johnson et a l . 1982). F i e l d experiments are now conducted more commonly i n an e f f o r t to q u a n t i f y r e l a t i o n s h i p s between p a r t i c u l a r s o i l v a r i a b l e s and p l a n t species or v e g e t a t i o n (Goldberg 1985; Tilman 1987) . Summarizing the r e s u l t s of these s t u d i e s i s d i f f i c u l t as environmental c o n d i t i o n s and v e g e t a t i o n vary tremen-dously. Of course, some s o i l and s i t e v a r i a b l e s commonly exert an i n f l u e n c e on species d i s t r i b u t i o n and abundance. On o l d f i e l d s , s o i l N i n f l u e n c e d p l a n t biomass and height, and species d i v e r s i t y (Tilman 1987) . In a Harvard f o r e s t , Walker (1975) found t h a t disturbance, moisture, t e x t u r e , and s o i l depth e x p l a i n e d about 40% of the v a r i a t i o n i n the v e g e t a t i o n . Highly productive f o r e s t s i t e s i n Alaska are a s s o c i a t e d with warmer s o i l temperatures, smaller 9 accumulations of organic l a y e r s and lower C:N r a t i o s (Yarie 1983). Vegetation of a r i d regions, p a r t i c u l a r l y North American grasslands where the current study area i s l o c a t e d , a l s o show tremendous v a r i a t i o n i n the v a r i a b l e s c o n t r o l l i n g p l a n t growth. A study of s o i l p r o p e r t i e s a s s o c i a t e d w i t h grasses on the U.S. Great P l a i n s i n d i c a t e d t h a t temperature and moisture regimes, pH, water-holding c a p a c i t y , c l a y content, bulk d e n s i t y and s o i l t e x t u r e were important (Platou et a l . 1986). On western Montana rangelands, biomass was s i g n i f i c a n t l y c o r r e l a t e d w i t h the t h i c k n e s s of the m o l l i c epipedon, and organic matter and N l e v e l s i n the A h o r i z o n (Munn et a l . 1978). Vegetation c o l o n i z i n g Utah roadways responded to s o i l t e x t u r e , slope, s o i l depth, aspect, s a l i n i t y , pH, and i n f i l t r a t i o n r a t e (Jaynes and Harper 1978). The d i s t r i b u t i o n of s e v e r a l s a l t b u s h species (Atriplex spp.) was e x p l a i n e d by pH, e l e c t r i c a l c o n d u c t i v i t y (EC), and sodium adsorption r a t i o s (SAR) (Hodgkinson 1987) . H u l e t t et a l . (1966) i d e n t i f i e d two g r a d i e n t s , moisture and the degree of dune s t a b i l i t y , t hat best accounted f o r v e g e t a t i o n p a t t e r n s on sand dunes i n the Saskatchewan grass l a n d s . In southern A l b e r t a , slope, aspect, and slope p o s i t i o n and shape i n f l u e n c e the s o i l moisture and n u t r i e n t regimes on coulee slopes, which i n t u r n shape the g r a s s l a n d communities ( L i e f f e r s and L a r k i n - L i e f f e r s 1987). 10 In Saskatchewan wetlands, four environmental g r a d i e n t s accounted f o r most of the v a r i a t i o n i n the data ( i n decreasing importance): 1) p l a n t disturbance, 2) a v a i l a b l e n u t r i e n t s , 3) water regime, and 4) s a l i n i t y (Walker and Wehrhahn 1971). P l a n t species d i s t r i b u t i o n i n a B.C. brack-i s h marsh was a s s o c i a t e d w i t h 1) d u r a t i o n of submergence, 2) pore water s a l i n i t y , 3) substrate water content, and 4) sediment t e x t u r e (Hutchinson 1980). Research on v e g e t a t i o n - s o i l r e l a t i o n s h i p s i n the A l b e r t a parkland and p r a i r i e has been minimal; moreover, the d i s t u r b e d and reclaimed s i t e s i n these areas remain unstudied. Studies of man-made ea r t h i s l a n d s are extremely r a r e . A study of these i s l a n d s was conducted i n Saskatchewan f o r DU (Hamm 1982). Hamm (1982) de s c r i b e d and q u a l i t a t i v e l y e x p l a i n e d the p l a n t - s o i l p a tterns on man-made ea r t h i s l a n d s . S o i l s a l i n i t y and, to a l e s s e r degree, organic matter and f e r t i l i t y l e v e l s were i d e n t i f i e d as important i n f l u e n c e s on i s l a n d v e g e t a t i o n . The current study describes and e x p l a i n s the p l a n t - s o i l r e l a t i o n s h i p s on 12 man-made ea r t h i s l a n d s i n c e n t r a l A l b e r t a . The s o i l s and vegetation were sampled at the same l e v e l of i n t e n s i t y and, using c o r r e l a t i o n a n a l y s i s , the r e l a t i o n s h i p s were examined q u a n t i t a t i v e l y , as w e l l as q u a l i t a t i v e l y . 11 3. H Y P O T H E S E S 1. A l t e r n a t e Hypothesis: S o i l and s i t e c o n d i t i o n s i n f l u e n c e v e g e t a t i o n composition when expressed as f o l i a r cover. N u l l Hypothesis: V e g e t a t i o n composition i s not r e l a t e d t o s o i l and s i t e c o n d i t i o n s . 2. A l t e r n a t e Hypothesis: The c o n t r i b u t i o n of nonseeded s p e c i e s t o i s l a n d v e g e t a t i v e cover i s i n f l u e n c e d by s o i l and s i t e c o n d i t i o n s . N u l l Hypothesis: Nonseeded s p e c i e s cover i s not r e l a t e d t o s o i l and s i t e c o n d i t i o n s . 12 4. STUDY AREA A. LOCATION The twelve study wetlands are l o c a t e d w i t h i n the aspen parkland ecoregion of c e n t r a l A l b e r t a (Strong and Leggat 1981) , i n an area bounded by T o f i e l d , Wetaskiwin, and S t e t t l e r i n the west and Czar i n the east. A l l the wetlands except Houcher Lake and F l a t , Paulgaard Marsh and Hebert Lake, occur w i t h i n the aspen subregion. The l a t t e r four occur w i t h i n the groveland subregion. Figure 1 shows the general l o c a t i o n s of the wetlands and Table 4.1 provides the exact l o c a t i o n s . Table 4.1. Locations of study wetlands. WETLAND ELEVATION (m) LOCATIONS3 B u t t e r Lake 678 35 - 51 - 17 _ W4 Hebert Lake 834 19 & 2 0 - 37 - 18 - W4 Houcher Lake 675 4, 5 & 8 - 40 - 6 - W4 and F l a t 32 - 39 - 6 - W4 Kingston Slough 740 2 & 3 - 48 - 20 - W.4 34 & 35 - 47 - 20 - W4 Louis Lake 788 29, 31 & 32 - 45 - 25 - W4 Marstrand P r o j e c t 747 20 - 48 - 19 - W4 Paulgaard Marsh. 655 4 & 9 - 37 - 3 - W4 Reta P r o j e c t 732 17 & 20 - 48 - 18 - W4 Ro l l y v i e w Marsh 762 18 - 49 - 22 - W4 Waskwei Creek 686 16, 21, 22, 3 & 33 - 50 - 16 - W4 Z i l k e Marsh 769 6 & 7 - 46 - 24 — W4 Land l o c a t i o n : sections. - township - range - west of 4th meridian. 13 LEGEND Study S i t e s 1. B u t t e r Lake 2. Hebert Lake 3. Houcher F l a t & Lake 4. Kingston Slough 5. Louis Lake 6. Marstrand P r o j e c t 7. Paulgaard Marsh 8. Reta P r o j e c t 9. R o l l y v i e w Marsh 10. Waskwei Creek 11. Z i l k e Marsh C i t i e s A. Edmonton B. Red Deer C. Camrose D. Wainwright Fi g u r e 1. L o c a t i o n of study wetlands i n the c e n t r a l aspen parkland ecoregion (outlined) of A l b e r t a . 14 B. CLIMATE The c l i m a t e of the study area t y p i f i e s c o n t i n e n t a l areas of northern l a t i t u d e s . The winters are long, c o l d and dry, whereas the summers are short and moderately warm. Temperature extremes of < -40°C and > 35°C are p o s s i b l e (Atmospheric Environment S e r v i c e 1982). The f r o s t - f r e e p e r i o d averages 95 days (Strong and Leggat 1981) . The p r e v a i l i n g winds are from the northwest; however, west winds are common. The Chinook b e l t extends north to the southern part of the study area. In t h i s r e g i o n , 8 to 13 days during January, February and March have temperatures > 4°C (Langley 1967). Mean annual p r e c i p i t a t i o n i n the aspen p a r k l a n d i s 4.50 mm. P r e c i p i t a t i o n f o r the months of May - September averages 300 mm (Strong and Leggat 1981). The study area l i e s w i t h i n the dry subhumid moisture region of Canada, where there i s l i t t l e or no water surplus i n any season (Sanderson 1948). This region has an annual water d e f i c i t because of low humidity,. . frequent high winds and low p r e c i p i t a t i o n . Although t o t a l summer p r e c i p i t a t i o n i s low i n both the parkland and p r a i r i e regions, a p p r o x i -mately 40% more r a i n f a l l s d uring J u l y and August i n the parkland. This f a c t o r reduces moisture s t r e s s and enables t r e e s such as aspen poplar (Populus tremuloides) to grow (Strong and Leggat 1981). The t h i r t y - y e a r normals f o r S t e t t l e r , Hughenden and Camrose m e t e o r o l o g i c a l s t a t i o n s are l i s t e d i n Table 4.2. 15 The s t a t i o n s are l o c a t e d w i t h i n the study area. Camrose weather data f o r the two summers of data c o l l e c t i o n and the t h i r t y - y e a r normal are presented i n Table 4.3. Table 4.2. C l i m a t i c averages f o r the S t e t t l e r , Hughenden, and Camrose, A l b e r t a m e t e o r o l o g i c a l s t a t i o n s , 1951 - 1980 (Atmospheric Environment Se r v i c e 1982) . M e t e o r o l o g i c a l S t a t i o n 3 S t e t t l e r Hughenden Camrose Mean Annual Temperature (°C) 2.5 2.0 1.9 Extreme Maximum Temperature (°C) 37.8 34.4 36.7 Extreme Minimum Temperature (°C) -46.7 -44.0 -47.8 Annual P r e c i p i t a t i o n (mm) 431.3 390.4 453.2 Annual Snowfall (mm) 108.8 96.1 117.0 Annual R a i n f a l l (mm) 321.5 293.2 334.5 F r o s t Free P e r i o d (days) 118 97 113 Annual P o t e n t i a l Evaporation (mm)b 500 508-559 554.1 a S t e t t l e r : 823 m ASL; 52° 18' N, 112° 42' W. Hughenden: 694 m ASL; 52° 31' N, 110° 58' W. Camrose: 732 m ASL; 53° 0.1' N, 112° 50' W. b S t e t t l e r : Data from Trochu Equity s t a t i o n ( A l b e r t a E c o l o g i c a l Survey 1979) . Hughenden: Canadian Land Inventory (1978). Camrose: C a l c u l a t e d lake evaporation, from E l l e r s l i e S t a t i o n . 16 Table 4.3 P r e c i p i t a t i o n and temperature f o r Camrose, A l b e r t a , 1985 and 1986 (Atmospheric Environment Service 1982) . Average Monthly Average D a i l y Month P r e c i p i t a t i o n (cm) Temperature (°C) 1985 .1986 Normals 1985 1986 Normals January 12.6 20.8 27.0 -9.9 -6.4 -16.9 February 21.6 10.6 19.1 -12.6 -13.4 -11. 9 March 9.8 28.8 19.7 -2.2 0.6 -11. 6 A p r i l 25.4 118.6 19.6 4.6 3.7 3.3 May 31.6 78.8 46.0 12.3 11.7 10.6 June 44.0 44.4 79.6 12.8 14 . 9 14.4 J u l y 24.6 152.6 74 .1 17 .5 15.2 16.7 August 131.1 33.4 74.4 14.4 16.2 15.5 September 32.1 67.8 39.7 7.3 8 . 6 10.1 October 21.2 15.8 . 15.4 3.4 6.8 4 . 6 November 13.0 20.2 16.8 -13.4 -8.3 -4.9 December 35. 6 7.2 21.8 -6.4 -5.7 -12.0 Total/Mean 402.6 598.8 453.2 2.3 3.7 1.9 C. SOILS The m a j o r i t y of the study area l i e s w i t h i n the Black Chernozem s o i l zone. Houcher Lake and F l a t , Paulgaard Marsh and Hebert Lake occur i n the Dark Brown S o i l Zone, i n d i c a t i n g a s l i g h t l y d r i e r c l i m a t e . Most s o i l s i n the area formed on g l a c i a l t i l l d e p o s i t s ; however, s o i l s have a l s o developed on more recent a l l u v i a l and a e o l i o n deposits (Wyatt et a l . 1938; Bowser et a l . 1947; Bowser et a l . 1962). Chernozems develop under gra s s l a n d or g r a s s l a n d - f o r e s t v e g e t a t i o n . They occur p r i m a r i l y i n the c o l d , s u b a r i d to subhumid I n t e r i o r P l a i n s of western Canada. The decom-p o s i t i o n of herbaceous species produces a surface h o r i z o n 17 c h a r a c t e r i z e d by a dark c o l o u r ( i n d i c a t i n g high organic accumulation) and granular s t r u c t u r e . The s a l t content of these s o i l s i s high r e l a t i v e to most other s o i l orders. Base s a t u r a t i o n ( n e u t r a l cations) i s more than 80% and Ca i s the predominant exchangeable c a t i o n (Canada S o i l Survey Committee 1978). In general, the study wetlands occur i n areas where Black and Dark Brown Chernozems predominate; however, these s o i l s do not n e c e s s a r i l y occur adjacent t o the sloughs. The upland s o i l s surrounding Kingston Slough, Reta P r o j e c t , Marstrand P r o j e c t and Waskwei Creek are predominantly So l o d i z e d Solonetz and s e c o n d a r i l y Black Chernozems (Wyatt et a l . 1938; Bowser et a l . 1947; Bowser et a l . 1962). The upland s o i l s surrounding B u t t e r Lake are predominantly Black Chernozems and s e c o n d a r i l y S o l o d i z e d Solonetz; Hebert Lake upland s o i i s are predominantly S o l o d i z e d Solonetz. The remaining p r o j e c t s , Houcher F l a t and Lake, Louis Lake, and Paulgaard, R o l l y v i e w and Z i l k e Marshes are surrounded by Black, Dark Brown and Dark Grey Chernozems. S o l o n e t z i c s o i l s g e n e r a l l y develop from parent m a t e r i a l w i t h r e l a t i v e l y high sodium s a l t l e v e l s , under a g r a s s l a n d or herbaceous v e g e t a t i o n . They are u s u a l l y found i n a s s o c i a t i o n with Chernozems. S o l o n e t z i c s o i l s can a l s o develop i n discharge areas r e c e i v i n g groundwater w i t h excess sodium s a l t s . The subsurface (B) h o r i z o n of these s o i l s has a p r i s m a t i c or columnar s t r u c t u r e which develops from the sodium-induced d e f l o c c u l a t i o n and l e a c h i n g of sodium 18 s a t u r a t e d c o l l o i d s from the surface horizons and t h e i r subsequent d e p o s i t i o n at lower l e v e l s . This d i a g n o s t i c h o r i z o n (Bn or Bnt) i s hard when dry and r e l a t i v e l y impermeable when wet; consequently, p l a n t growth i s o f t e n hindered. S o i l s surrounding wetlands i n f l u e n c e t h e i r v e g e t a t i o n and water q u a l i t y because of groundwater drainage through the s o i l s . Groundwater p i c k s up s a l t s from the s o i l and dep o s i t s them i n wetlands and seepage areas. S o i l s not immediately adjacent to a wetland can i n f l u e n c e i t s i m i l a r l y . S o l o n e t z i c s o i l s and t h e i r parent m a t e r i a l i n f l u e n c e wetland v e g e t a t i o n and water because they c o n t r i b u t e sodium s a l t s t o groundwater. Sodium s a l t s i n c rease the a l k a l i n i t y and s a l i n i t y of s o i l s and water. The s o i l s u n d e r l y i n g the wetlands tend to r e f l e c t the surrounding s o i l s , at l e a s t i n terms of t e x t u r e and chemical composition; however, wetland s o i l s are u s u a l l y l a c u s t r i n e i n o r i g i n . S o i l s of d e p r e s s i o n a l areas w i t h i n Chernozemic and S o l o n e t z i c areas are o f t e n G l e y s o l s (Orthic Humic, Rego Humic, O r t h i c Luvic and Rego), Regosols or Organics. 19 D. TOPOGRAPHY AND GEOLOGY A l l of the study wetlands occur on l e v e l to und u l a t i n g topography, except Louis Lake, R o l l y v i e w Marsh and, t o a l e s s e r degree, Houcher Lake and F l a t , which are s i t u a t e d i n g e n t l y r o l l i n g to r o l l i n g lands. E l e v a t i o n s i n the study area range from 823 m above sea l e v e l (ASL) at S t e t t l e r i n the south, t o 788 m ASL at Louis Lake i n the northwest, to 655 m ASL at Paulgaard Marsh i n the east (Table 4.1). Debris outpouring from the mountains t o the west, during the f i n a l phase of the Cretaceous and T e r t i a r y Seas, produced the bedrock formations i n A l b e r t a . The deposits c o n s i s t of shale, s i l t s t o n e , sandstone and minor c o a l seams l a i d down i n marine, brackish-water, freshwater and sub-a e r i a l l a y e r s . The bedrock surface slopes g r a d u a l l y to the west and southwest ( S t a l k e r 1972). Three bedrock formations occur w i t h i n the study area. The western s e c t i o n , and bulk of the study area, i s un d e r l a i n by the Edmonton formation. A narrow band of the Bearpaw formation runs roughly north t o south along the eastern s i d e of the Edmonton formation. The B e l l y R i v e r formation u n d e r l i e s the eastern s i d e . The Edmonton formation not only u n d e r l i e s most of the p r o j e c t s , but i t a l s o c o n t r i b u t e d the most m a t e r i a l t o the g l a c i a l d r i f t , which i s the s o i l s ' parent m a t e r i a l . The Edmonton formation i s a brackish-water formation from the Upper Cretaceous p e r i o d , composed of b e n t o n i t i c sandstones, 20 sandy shales, bentonitic clays and coal seams. Bentonite i s the p r e v a i l l i n g constituent throughout the formation (Bowser et a l . 1962). The Bearpaw formation i s a marine deposit composed prim a r i l y of dark-coloured shales with some bentonite and s a l t . This formation contributed much of the gypsum to the g l a c i a l t i l l i n the area. Most s a l t - a f f e c t e d s o i l s are found on t i l l p rimarily composed of Bearpaw shale. The B e l l y River formation i s a fresh and brackish-water deposit composed of bentonitic sandstones, carbonaceous shales with coal seams, ironstone nodules and gypsum c r y s t a l s . The uppermost bed of the Be l l y River formation i s c a l l e d the Pale Beds. The Edmonton formation underlies the following projects: Hebert Lake, Kingston Slough, Louis Lake, Marstrand Project, Reta Project, and Rollyview and Zilke Marshes. Waskwei Creek i s underlain by the Bearpaw formation, and Butter Lake, Houcher F l a t and Lake, and Paulgaard Marsh are underlain by the Belly River formation. During the Keewatin g l a c i a t i o n , ice moved southwest from the Hudson Bay region carrying and mixing g l a c i a l t i l l with the underlying bedrock. The mixed t i l l covering the study area i s the s o i l s ' parent material. S o i l s on Edmonton bedrock developed from t i l l p rimarily of Edmonton o r i g i n . S o i l s adjacent to Butter Lake, which i s underlain by Belly River, and Waskwei Creek, which i s underlain by Bearpaw, also developed on t i l l p rimarily of Edmonton o r i g i n . S o i l s 21 adjacent t o Houcher Lake and Paulgaard Marsh developed from mixed t i l l and outwash sand parent m a t e r i a l . E. DRAINAGE The e n t i r e study area l i e s w i t h i n the North Saskatchewan R i v e r watershed, and most of the p r o j e c t s occur i n an area drained v i a the B a t t l e R i v e r . Paulgaard Marsh and Houcher Lake and F l a t d r a i n v i a E y e h i l l Creek and Ribstone Creek, r e s p e c t i v e l y , i n t o the B a t t l e R i v e r . Z i l k e Marsh and Louis Lake d r a i n i n t o the B a t t l e R i v e r v i a Bigstone and then Pipestone Creeks. Reta P r o j e c t i s drained i n t e r m i t t e n t l y by an unnamed creek i n t o Driedmeat Creek and then the B a t t l e R i v e r . Kingston Slough d r a i n s i n t o the B a t t l e R i v e r v i a Camrose Creek. Hebert Lake d r a i n s i n t o Marion Lake and v i a a high water o u t l e t to B i g k n i f e Creek and B a t t l e R i v e r . B u t t e r Lake, Marstrand P r o j e c t and R o l l y v i e w Marsh are i s o l a t e d b a s i n s . Waskwei Creek d r a i n s i n t o the V e r m i l i o n R i v e r . F. HISTORY AND LAND USE The o r i g i n a l i n h a b i t a n t s of the aspen parkland were Algonquin and Athabascan Indians, a nomadic people who hunted the abundant w i l d l i f e . Bison (Bison bison), w a p i t i (Cervus elaphus), pronghorn antelope (Antilocapra americana), mule deer (Odocoileus hemionus), w h i t e - t a i l e d deer (Odocoileus virginianus) , f urbearers and the o c c a s i o n a l 22 moose (Alces alces) were found i n the r e g i o n . Indians used f i r e as a means of communication and as a t o o l f o r modifying the movements of b i s o n , t h e i r major food source. Their use of f i r e probably had the greatest impact on the land (Wroe 1971) . Anthony Henday t r a v e l l e d through the B a t t l e and North Saskatchewan R i v e r s region i n 1754 and 1755 i n an attempt to persuade the Indians to b r i n g f u r s to the Hudson Bay. F o l l o w i n g Henday's journey, the B a t t l e R i v e r became an important route f o r f u r t r a d e r s and t r a p p e r s . In the l a t e 1850s, Captain John P a l l i s e r ' s e x p e d i t i o n to the Canadian West f o r the B r i t i s h Government passed through the area (Morton 1963). In the 17th and 18th c e n t u r i e s , f u r t r a d e r s and bounty hunters were a t t r a c t e d t o the aspen parkland because of the abundant w i l d l i f e . In the l a t e 1800s and e a r l y 1900s s e t t l e r s moved i n t o the area to homestead. By the l a t e 1800s animals such as b i s o n and wolf (Canis lupus) had disappeared ( B i r d and B i r d 1967). A g r i c u l t u r a l settlement i n the region began i n the 1880s, but general settlement began i n the 1890s and e a r l y 1900s, c o i n c i d i n g with the completion of the r a i l w a y s . Settlement abated during the 1930s, a c c e l e r a t i n g again a f t e r World War I I . By 1960 much of the n a t i v e parkland v e g e t a t i o n had been a l t e r e d by l i v e s t o c k g r a z i n g or broken f o r f i e l d crops ( B i r d and B i r d 1967). Since settlement 90 23 t o 95% of n a t i v e parkland v e g e t a t i o n i n Canada has been a l t e r e d or destroyed (North 1976). A g r i c u l t u r e and o i l and gas production are major land uses i n the study area. Major a g r i c u l t u r a l products i n c l u d e wheat, b a r l e y , rye, oats, canola, beef, and p o u l t r y . G. VEGETATION The e n t i r e study area i s l o c a t e d w i t h i n the aspen parkland region (Figures 1, 2 and 3). Nomenclature f o l l o w s Moss (1983) and Looman and Best (1979) f o r v a s c u l a r p l a n t s . This region has been v a r i o u s l y d e s c r i b e d as a t r a n s i t i o n zone between the b o r e a l f o r e s t and the p r a i r i e , a subclimax ecotone, and a complex of f o r e s t communities i n g r a s s l a n d . Moss (1932) supported the former d e s c r i p t i o n ; he d i v i d e d the aspen parkland i n t o the poplar a s s o c i a t i o n and the grove b e l t . The l a t t e r c o n s i s t s of a patchwork of aspen poplar (Populus tremuloides) groves and p r a i r i e g r assland, while the poplar a s s o c i a t i o n i s p r i m a r i l y aspen f o r e s t . In the northern p a r t of the region Moss (1932) considered white spruce (Picea glauca) t o be the climax s p e c i e s . B i r d (1930) regarded the aspen parkland as a subclimax ecotone between the coniferous f o r e s t and the p r a i r i e . Coupland and Brayshaw (1953) de s c r i b e d the parkland as an i n t e r s p e r s i o n of f o r e s t communities i n g r a s s l a n d ; they considered the ecotone to e x i s t around each i n d i v i d u a l aspen 24 Figure 2. A e r i a l view of a DU wetland set i n n a t i v e aspen parkland. This p a r t i c u l a r p r o j e c t , Whitefront P r o j e c t , i s l o c a t e d i n e a s t - c e n t r a l A l b e r t a (May 1980). The dark green clumps are aspen poplar stands d i s t r i b u t e d throughout grasslands. Note the dam and 10 earth i s l a n d s i n the wetland. C u l t i v a t e d f i e l d s are v i s i b l e i n the upper part of the photograph and i n the lower r i g h t corner. 25 Figure 3. A e r i a l photograph, taken i n May 1980, of t y p i c a l man-made earth i s l a n d s i n S i s i b Lake. Note the c u l t i v a t e d and hayed uplands. The c u l t i v a t e d f i e l d s provide poor n e s t i n g cover. Several aspen groves are v i s i b l e a l s o . 26 grove, r a t h e r than at the i n t e r f a c e of the northern f o r e s t and p r a i r i e . Moss (1932) recognized two major v e g e t a t i o n types i n the aspen parkland: the aspen community of moist and s h e l t e r e d s i t e s , and the p r a i r i e g r a s s l a n d complex of d r i e r and more exposed s i t e s . In A l b e r t a , north and south regions of the g r a s s l a n d are d i s t i n g u i s h e d , c o i n c i d i n g w i t h the Dark Brown and Brown s o i l zones, r e s p e c t i v e l y . Moss des c r i b e d the g r a s s l a n d of the parkland as northern p r a i r i e with i s l a n d s of southern p r a i r i e i n t e r s p e r s e d . Rough fescue (Festuca scabrella) and June grass (Koeleria cristata) are the predominant northern p r a i r i e s p e c i e s , while wheatgrasses (Agropyron spp.), blue grama (Bouteloua gracilis) and needle grass (Stipa spp.) are important c o n s t i t u e n t s of the southern p r a i r i e . Numerous potholes, sloughs and lakes occur throughout the aspen parkland. The s a l i n i t y and a l k a l i n i t y of these wetlands v a r i e s considerably, depending upon the l o c a l s o i l , geology and groundwater q u a l i t y . The uplands surrounding the wetlands are o f t e n vegetated with aspen poplar and balsam poplar (Populus balsamifera) . C l o s e r t o the wetland on wetter s o i l , w i l l o w s (Salix spp.) are common. Common emergent species of freshwater wetlands i n c l u d e c a t t a i l (Typha latifolia) , whitetop (Scolochloa festucaceae), spikerush (Eleocharis p a l u s t r i s ) , slough grass (Beckmannia syzigachne), sedge species (Carex rostrata, C. aquatilis, and C. atherodes) and softstem and hardstem 27 b u l r u s h (Scirpus validus and S. acutus) . Drawdown (the s h o r e l i n e area over which waterbodies p e r i o d i c a l l y f l u c t u a t e ) and s h o r e l i n e species i n c l u d e fowl bluegrass (Poa p a l u s t r i s ) , Canada t h i s t l e , f o x t a i l b a r l e y (Hordeum jubatum) , B a l t i c rush (Juncus b a l t i c u s ) , reed grass (Calamagrostis inexpansa and C. stricta), manna grass (Glyceria striata), s i l v e r w e e d (Potentilla anserina) , goosefoot (Chenopodium spp.), mint (Mentha arvensis) , and sedges (Carex spp.). Submergent and f l o a t i n g species i n c l u d e duckweeds (Lemna minor and L. trisulca) , northern w a t e r - m i l f o i l (Myriophyl1 um exalbescens) , sago pondweed (Potamogeton pectinatus) , Richardson's pondweed (Potamogeton r i c h a r d s o n i i ) , c o o n t a i l (Ceratophyllum demersum), and m a r e ' s - t a i l (Hippuris vulgaris). F l o r a of s a l i n e and a l k a l i n e sloughs i s o f t e n s i m i l a r to t h a t d e s c r i b e d above, but there are species charac-t e r i s t i c of such wetlands. C h a r a c t e r i s t i c emergents i n c l u d e a l k a l i b u l r u s h (Scirpus paludosus); drawdown and s h o r e l i n e species i n c l u d e s a l t meadow grass (Puccinellia nuttalliana), s a l t grass (Distichlis stricta), western s e a - b l i t e (Suaeda calceoliformis) , samphire (Salicornia eu'ropaea) , and sea milkwort (Glaux maritima) . Wigeon grass (Ruppia maritima) and large-sheath pondweed (Potamogeton vaginatus) are common submergents of s a l i n e sloughs. 28 H. WILDLIFE The aspen parkland i s r i c h i n w i l d l i f e . W i l d l i f e nomenclature f o l l o w s B a n f i e l d (1974) f o r mammals, American O r n i t h o l o g i s t s ' Union (1982) f o r b i r d s , and Cook (1980) f o r r e p t i l e s and amphibians. Large mammals i n h a b i t i n g the area i n c l u d e mule deer, w h i t e - t a i l e d deer, coyote (Canis latrans) and red fox (Vulpes wipes) . Other common mammals i n c l u d e s t r i p e d skunk (Mephitis mephitis) , beaver (Castor canadensis), muskrat (Ondatra zibethicus), snowshoe hare (Lepus . americana), and Richardson's ground s q u i r r e l (Spermophilus r i c h a r d s o n i i ) . B i r d l i f e , wetland species i n p a r t i c u l a r , i s d i v e r s e and r i c h . Common waterfowl species i n c l u d e Canada geese (Branta canadensis), m a l l a r d , gadwall, Northern p i n t a i l (Anas acuta), green-winged and blue-winged t e a l (Anas crecca and A. discors), American wigeon (Anas americana), Northern shoveler (Anas clypeata), redhead (Aythya americana) , canvasback (Aythya valisineria) , and l e s s e r scaup (Aythya affinis) . Red-necked and horned grebes (Podiceps grisegena and P. auritus) , great blue heron (Ardea herodias) , American coot (Fulica americana), r i n g - b i l l e d g u l l s (Larus delawarensis) , yellow-headed and red-winged b l a c k b i r d s (Xanthocephalus xanthocephalus and Agelaius phoeniceus), and numerous shorebirds and songbirds are common wetland s p e c i e s . Because of the abundant wetlands and waterfowl i n the parkland, t h i s region has been termed the "Duck Factory". 29 Approximately 75% of a l l North American duck production occurs i n the Canadian aspen parkland and p r a i r i e s . Common upland b i r d species i n c l u d e r e d - t a i l e d hawk (Buteo jamaicensis), Swainson's hawk (Buteo swainsoni) , Northern f l i c k e r (Colaptes auratus), Eastern k i n g b i r d (Tyrannus tyrannus), barn swallow (Hirundo rustica), American crow (Corvus brachyrhynchos) , black-capped chickadee (Parus atricapillus), American r o b i n (Turdus migratorius), yellow warbler (Dendroica petechia), and vesper sparrow (Poocetes gramineus) . Tiger salamander (Ambystoma tigrinum), Canadian toad (Bufo americanus hemiophrys), wood f r o g (Rana sylvatica) and bo r e a l chorus frogs (Pseudacris triseriata maculata) are amphibians i n h a b i t i n g the aspen parkland. P l a i n s g a r t e r snake (Thamnophis radix) a l s o i n h a b i t s the parkland. I. DUCKS UNLIMITED CANADA PROJECTS Ducks U n l i m i t e d i s an i n t e r n a t i o n a l , p r i v a t e , non-p r o f i t c onservation o r g a n i z a t i o n dedicated to the perp e t u a t i o n and increase of North America's waterfowl resources through r e s t o r a t i o n , p r e s e r v a t i o n and c r e a t i o n of prime breeding h a b i t a t i n Canada (Ducks U n l i m i t e d Canada's statement of purpose). Ducks U n l i m i t e d Canada works w i t h landowners on a fr e e easement b a s i s to develop or maintain wetlands. Development u s u a l l y i n v o l v e s the c o n s t r u c t i o n of an o u t l e t c o n t r o l s t r u c t u r e so tha t water l e v e l s can be c o n t r o l l e d . In 30 a d d i t i o n , areas of dense emergent v e g e t a t i o n (e.g. c a t t a i l s ) may be opened by l e v e l d i t c h i n g through the area w i t h a backhoe or d r a g l i n e . Earth i s l a n d s are o f t e n b u i l t i n wetlands to provide upland n e s t i n g cover and secure l o a f i n g s i t e s (Figures 2 and 3). These i s l a n d s are b u i l t by dredging, p i l i n g and shaping wetland bottom sediment w i t h a backhoe or d r a g l i n e . Earth i s l a n d s vary i n c o n s t r u c t i o n but they tend t o have about 1-1.5 m freeboard, and are 5-15 m wide and 20-40 m long (Figure 4) . Earth i s l a n d s , s p o i l p i l e s and c o n s t r u c t i o n s i t e s a s s o c i a t e d w i t h dams and dykes are harrowed, f e r t i l i z e d and seeded. E s t a b l i s h i n g v e g e t a t i o n on these s i t e s provides w i l d l i f e cover, b e a u t i f i e s the s i t e , and minimizes s o i l e r o s i o n and weed i n v a s i o n . 31 Figure 4. Photograph of a sodic, a l k a l i n e i s l a n d i n Kingston Slough (July 1986). This s p o i l p i l e was made when a d i t c h was constructed through a dense, c l o s e d stand of emergent v e g e t a t i o n . Sow t h i s t l e r o s e t t e s , f o x t a i l b a r l e y and t a l l wheatgrass are v i s i b l e . Note the l a r g e areas of bare s o i l , the 48 oz. j u i c e cans used to measure the i n f i l t r a t i o n r a t e , and the s t i c k s which mark the quadrat l o c a t i o n s . The aluminum p o i n t -i n t e r c e p t frame i s v i s i b l e at the f a r end of the i s l a n d . 32 5. MATERIALS AND METHODS A. WETLAND AND ISLAND SELECTION Wetland and i s l a n d s e l e c t i o n was made i n a stepwise process. F i r s t , to minimize environmental d i f f e r e n c e s , only wetlands w i t h i n the aspen parkland were considered (Figure 1) . In a d d i t i o n , only wetlands w i t h good records regarding i s l a n d c o n s t r u c t i o n , seeding and f e r t i l i s i n g were considered. This r e s t r i c t i o n r e s u l t e d i n the s e l e c t i o n of i s l a n d s between three and s i x years o l d (Appendix 1) . The wetlands s e l e c t e d by the above c o n s t r a i n t s i n c l u d e d i s l a n d s e x h i b i t i n g a wide range of s o i l c o n d i t i o n s : from s l i g h t l y a c i d to h i g h l y a l k a l i n e , and from low t o high organic matter l e v e l s . Using black-and-white and f a l s e - c o l o u r i n f r a r e d a e r i a l photographs, i s l a n d s w i t h p l a n t cover t y p i c a l ( i n terms of a r e a l cover and colour) f o r the wetland's i s l a n d s were chosen. To minimize the confounding i n f l u e n c e of waterfowl and l i v e s t o c k g r a z i n g on i s l a n d s , which sometimes occurs, i s l a n d s showing signs of gr a z i n g were excluded. The l a t t e r step was c a r r i e d out i n the f i e l d . In 1985, the f i r s t year of data c o l l e c t i o n , 20 i s l a n d s d i s t r i b u t e d among 12 wetlands were chosen. In 1986, 11 i s l a n d s and wetlands were s t u d i e d . The same wetlands were s t u d i e d i n 1986 as 1985, except f o r Reta P r o j e c t , which was h e a v i l y grazed and consequently dropped from the study. Houcher F l a t I s l a n d No. 1 was sampled i n 1986, but was 33 excluded from the data a n a l y s i s because i t too was e x c e s s i v e l y grazed. A f t e r the 1985 sampling season, a d e c i s i o n was made to concentrate s o l e l y on the r e l a t i o n s h i p between s o i l s and v e g e t a t i o n , as opposed to s o i l and v e g e t a t i o n d i f f e r e n c e s between i s l a n d s w i t h i n a wetland. (Owing t o the tremendous s o i l v a r i a b i l i t y and the l a r g e sample s i z e r e q u i r e d to represent the s o i l s , comparisons between i s l a n d s and years were not p o s s i b l e . ) As a r e s u l t , j u s t one i s l a n d from each wetland was sampled. B. SAMPLING METHODS A s e r i e s of environmental v a r i a b l e s was measured on each i s l a n d to i d e n t i f y which s o i l and s i t e c h a r a c t e r i s t i c s e x p l a i n e d the most v a r i a t i o n i n i s l a n d f o l i a r cover. Data c o l l e c t i o n was conducted i n J u l y and August of 1985 and 1986. Vegetation sampling began i n mid-July, a f t e r most v e g e t a t i v e growth was complete,- and was f i n i s h e d by mid to l a t e August, before the ve g e t a t i o n weathered and sh a t t e r e d . In g eneral, s o i l sampling was conducted c o n c u r r e n t l y with v e g e t a t i o n sampling. Throughout t h i s document, i s l a n d s u b s t r a t e i s r e f e r r e d t o as s o i l f o r ease of communication, although i t i s a c t u a l l y s p o i l m a t e r i a l . I slands were sampled w i t h i n a s t r a t i f i e d - r a n d o m framework. The i s l a n d s were d i v i d e d cross-wise i n t o 3 or 4 s e c t i o n s of equal area. One t r a n s e c t was randomly place d w i t h i n each s e c t i o n , running across the width of the i s l a n d 34 between the high water l i n e s . Between 2 and 4 quadrats were randomly l o c a t e d along each t r a n s e c t . Using a species area curve, the quadrat s i z e was set at 1 m2 (Greig-Smith 1983) . Sampling f o r v e g e t a t i o n , s o i l and s i t e v a r i a b l e s occurred at each quadrat, the b a s i c sampling u n i t . I n i t i a l l y i n 1985, sample a l l o c a t i o n was p r o p o r t i o n a l to area; however, midway through the 1985 season, sample a l l o c a t i o n was switched t o equal a l l o c a t i o n . The change was made because i s l a n d s i z e v a r i e d s u f f i c i e n t l y to change sample s i z e from 3 q u a d r a t s / i s l a n d to 12. Since only one i s l a n d per wetland was sampled i n 1986, equal a l l o c a t i o n ensured t h a t a l l i s l a n d s o i l s were represented by an adequate number of samples. This sampling s t r a t e g y provided a sample of s o i l s and v e g e t a t i o n s u i t a b l e f o r c o r r e l a t i o n a n a l y s i s (Sokal and Rohlf 1981). While sampling p r o p o r t i o n a l l y i n 1985, between 3 and 12 samples per i s l a n d were taken. A f t e r equal a l l o c a t i o n sampling was begun, each i s l a n d was sampled w i t h 6 quadrats. Except f o r Louis Lake, Marstrand P r o j e c t , Waskwei Creek and Z i l k e Marsh, two i s l a n d s per p r o j e c t were sampled i n 1985. In 1986, the study focused on 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 r a t h e r than d i f f e r e n c e s w i t h i n a wetland; consequently one i s l a n d from each p r o j e c t was sampled w i t h 8 quadrats. Quadrats sampled t o t a l l e d 142 i n 1985, and 88 i n 1986, p r o v i d i n g s u f f i c i e n t degrees of freedom f o r . c o r r e l a t i o n analyses. Quadrat d i s t r i b u t i o n between p r o j e c t s i s provided i n Table 5.1. 35 Table 5.1. D i s t r i b u t i o n of samples among i s l a n d s and wetlands. Wetlands 1985 Samples 1986 Samples I s l a n d 1 I s l a n d 2 I s l a n d 1 n n n B u t t e r Lake 12 6 8 Hebert Lake 6 6 8 Houcher F l a t 6 6 8 Houcher Lake 8 6 8 Kingston Slough 6 6 8 Louis Lake 10 _a 8 Marstrand P r o j e c t 12 - 8 Paulgaard Marsh 6 6 8 Reta P r o j e c t 3 3 0 R o l l y v i e w Marsh 6 6 8 Waskwei Creek 12 - 8 Z i l k e Marsh 10 — .8 I s l a n d T o t a l s 97 45 88 ANNUAL TOTALS 142 88 A second i s l a n d was not sampled. At each quadrat, p l a n t f o l i a r cover was measured using the v e r t i c a l pin-drop, or p o i n t - i n t e r c e p t , method (Taha et a l . 1983). In t h i s paper, p l a n t cover r e f e r s t o f o l i a r cover. T h i r t y pins per quadrat were dropped, and, i n 1985, only the p l a n t species h i t was recorded. In 1986, i f a p l a n t was not h i t , the s t r i k e was recorded as l i t t e r , bare s o i l , rock or water. I t was b e l i e v e d i n 1986 that a d d i t i o n a l i n f o r m a t i o n would be u s e f u l f o r i n t e r p r e t a t i o n of the p l a n t and s o i l data. A nestingboard was employed t o ob t a i n a second measure of v e g e t a t i v e cover. The nestingboard has four, square checker-board s t y l e sides (25, 6 x 6 cm squares/side) and i s used to r a p i d l y measure n e s t i n g cover (Jones 1968) . The apparatus i s placed i n the v e g e t a t i o n and the number of squares v i s i b l e are counted from four paces back. S o i l sampling f o r chemical a n a l y s i s c o n s i s t e d of f i v e 15 cm-deep s o i l samples cored and composited at each quadrat. S i t e data recorded at a quadrat i n c l u d e d slope, aspect, quadrat height-above-water, p o s i t i o n on i s l a n d ( i . e . , top, and upper, middle, and lower s l o p e ) , and microtopography (Table 5.2). Weather i n f o r m a t i o n was obtained from the c l o s e s t m e t e o r o l o g i c a l s t a t i o n , and i s l a n d c o n s t r u c t i o n and seeding h i s t o r i e s were obtained from DU (Appendix 1). Table 5.2 Microtopography c a t e g o r i e s used at each quadrat. Category C r i t e r i a 1 l e v e l (< 2 cm from the base to the top of the mound) 2 s l i g h t l y mounded (2 — 10 cm) 3 mounded (10 - 30 cm) 4 very mounded (> 30 cm) S o i l bulk d e n s i t y (BD) was measured at each quadrat u s i n g the excavation method (Blake 1965) . Hole volume was measured w i t h a p l a s t i c hole l i n e r and water; the s o i l was bagged, oven-dried and weighed. A e r a t i o n p o r o s i t y was measured on 21 undisturbed s o i l cores i n June 1986, when the s o i l was s t i l l moist. The cores were sa t u r a t e d sl o w l y to constant weight, weighed, and then p l a c e d on a t e n s i o n t a b l e w i t h 60 cm of water s u c t i o n . At e q u i l i b r i u m , between 24 and 36 hours l a t e r , the cores were weighed, oven-dried at 105°C and weighed again. T o t a l and a e r a t i o n (macropore) p o r o s i t y were c a l c u l a t e d from these r e s u l t s (de V r i e s , pers. comm.). To measure steady-state i n f i l t r a t i o n w i t h i n a quadrat, four - 48 oz. cans were sunk 10 cm i n t o moistened s o i l ( L a v k u l i c h pers. comm.). F i l l i n g the cans c o n s t a n t l y throughout the day brought the adjacent s o i l c l o s e to s a t u r a t i o n . Before l e a v i n g the i s l a n d i n the evening, the cans were f i l l e d and the time recorded. The f o l l o w i n g morning the water l e v e l and time were recorded. Empty cans were r e - f i l l e d , l e f t f o r a short time, and then measured. Obvious cracks and hollows, f o r example muskrat runs, were avoided when p l a c i n g the cans. C. SOIL ANALYSIS The composite s o i l samples were a i r - d r i e d t o a constant weight, and the chemical analyses performed on the f i n e (< 2 mm) f r a c t i o n . Table 5.3 l i s t s the analyses performed and the methods used. Most of these analyses were performed i n the U.B.C. Pedology Laboratory. P a c i f i c S o i l A n a l y s i s L t d . , Vancouver, analysed the s o i l f o r exchangeable and s o l u b l e c a t i o n s , c a t i o n exchange c a p a c i t y (CEC), and sa t u r a t e d paste e l e c t r i c a l c o n d u c t i v i t y (satEC). Because of the c o s t s , some analyses were completed on a subsample only. 38 Table 5.3 Methods and references of chemical and p h y s i c a l analyses performed on s o i l samples. A n a l y s i s Method Reference P Hw 1:2 (so i l : w a t e r ) McKeague (1978) P H C 1:2 ( s o i l : C a C l 2 ) McKeague (1978) E l e c t r i c a l C o n d u c t i v i t y 1:2 (soil:w a t e r ) McKeague (1978) EC & Soluble Cations Saturated Paste PSA a Exchangeable Cations NH4OAC, pH 7, Shaken 12 h PSA Cation Exchange NH4OAC, pH 7, Capacity Shaken 12 h PSA Organic Carbon Walkley-Black McKeague (1978) T o t a l Nitrogen Auto-analyzer Black (1965) Phosphorus Olsen Black (1965) Texture Hydrometer McKeague (1978) Bulk Density Excavation Blake (1965) I n f i l t r a t i o n Rate Si n g l e r i n g L a v k u l i c h (PC b) Pore D i s t r i b u t i o n Undisturbed core & te n s i o n t a b l e de V r i e s (PC) Carbonates HCl (10%) CSSC (1978) c P a c i f i c S o i l A n a l y s i s L t d . , Vancouver, B.C. Personal communication. Canada S o i l Survey Committee. In 1985, a l l s o i l samples (n = 138; 4 of the t o t a l 142 quadrats were not soil-sampled) were analysed f o r pH, EC (measured on a 1:2 s o i l to water s o l u t i o n ) , organic carbon (C) , and bulk d e n s i t y (BD) . Because of f i n a n c i a l c o n s t r a i n t s , a subsample was analysed f o r t o t a l N (n = 78) , exchangeable c a t i o n s (n = 72), phosphorus (n = 36), and t e x t u r e (n = 9). In 1986, a l l samples were analysed f o r pH, EC, C, BD, and exchangeable c a t i o n s (n = 80) . Soluble c a t i o n s , satEC, and t o t a l N were measured on a subsample (n = 26), as was pore d i s t r i b u t i o n (n = 21). 39 The number or degrees of freedom a v a i l a b l e f o r the Sums of Squares Residual depended on which v a r i a b l e s were i n c l u d e d i n the c o r r e l a t i o n a n a l y s i s . For example, i f i n 1985, pH, EC, C, and BD were c o r r e l a t e d against f o l i a r cover, the sample s i z e (n) would equal 138. I f the data a n a l y s i s i n c l u d e d t o t a l N, "n" would decrease t o 78; i f ca t i o n s were inc l u d e d , "n" would drop f u r t h e r to 72. S i m i l a r l y i n 1986, i f pH, EC, C and BD were analysed, the sample s i z e would be 80; i f t o t a l N or s o l u b l e c a t i o n s were added, the sample s i z e would drop to 26. References i n the RESULTS chapter to "the i n c l u s i o n of (certain) v a r i a b l e s " , r e f e r t o these reductions i n sample s i z e . D. DATA ANALYSIS The o b j e c t i v e s of the a n a l y s i s were t o e s t a b l i s h r e l a t i o n s h i p s between s o i l and s i t e v a r i a b l e s and p l a n t f o l i a r cover. V a r i a t i o n i n t o t a l (island) and i n d i v i d u a l species f o l i a r cover, i n r e l a t i o n to the environmental v a r i a b l e s , was analysed by stepwise m u l t i p l e c o r r e l a t i o n (Sokal and Rohlf 1981) . L i n e a r c o r r e l a t i o n i s the appropriate a n a l y s i s , as opposed to l i n e a r r e g r e s s i o n , because the X values, or s o i l and s i t e v a r i a b l e s , are not f i x e d , p r e c l u d i n g statements regarding cause and e f f e c t . The c r i t e r i o n f o r r e t a i n i n g or d e l e t i n g a v a r i a b l e was based on a 5% p r o b a b i l i t y l e v e l . I n i t i a l l y , l o g a r i t h m i c t r a n s f o r m a t i o n s to reduce h e t e r o s c e d a s t i c i t y , and angular tra n s f o r m a t i o n s of percent data were a p p l i e d to the raw 40 data; however, as the choice and s i g n i f i c a n c e of environmental v a r i a b l e s was not changed, subsequent analyses were conducted on the untransformed data (Eaton, pers. comm.) . C o r r e l a t i o n analyses were performed on a l l 7 seeded species recorded i n quadrats, and the 6 predominant nonseeded s p e c i e s . Although analyses could have been performed on other nonseeded species a l s o , they were e i t h e r not frequent enough or provided i n s u f f i c i e n t f o l i a r cover to make i t worthwhile. The sample s i z e (n) f o r m u l t i p l e c o r r e l a t i o n a n a l y s i s was determined by ensuring t h a t the number of observations provided the Sum of Squares R e s i d u a l w i t h > 25 degrees of freedom, u s i n g the formula: 25 < (n-m-1) < 100, where n i s the number of observations f o r each p a i r of X and Y, and m i s the number of p r e d i c t o r v a r i a b l e s (Kozak, pers. comm.). At 25 degrees of freedom, s t a t i s t i c s approach t h e i r p o p u l a t i o n parameters; consequently,, l a r g e r sample s i z e s are o f t e n not needed (Gove et a l . 1982) . A c h i e v i n g more than 100 degrees of freedom u s u a l l y means tha t an unnecessary amount of sampling was conducted (Kozak, pers. comm.) . Both stepwise and a l l p o s s i b l e combinations (APC) c o r r e l a t i o n a n a l y s i s was performed. I n t e r p r e t a t i o n of the data analyses were based on three or- fewer p r e d i c t o r v a r i a b l e s . More than three v a r i a b l e s makes the 41 i n t e r p r e t a t i o n h i g h l y complex and i m p r a c t i c a l f o r management purposes. Exceptions to t h i s p r a c t i c e occurred when stepwise a n a l y s i s i d e n t i f i e d a r e l a t i o n s h i p i n v o l v i n g four, and on one occasion f i v e , v a r i a b l e s . The APC r e s u l t s u s u a l l y supported the stepwise r e s u l t s , so r e l a t i o n s h i p s i d e n t i f i e d by the l a t t e r method were g e n e r a l l y accepted. In the RESULTS chapter, " v a r i a b l e subsets" or "subsets" r e f e r s t o the combination of environmental v a r i a b l e s w i t h which a p a r t i c u l a r f o l i a r cover measure i s c o r r e l a t e d . A l l analyses and d e s c r i p t i v e s t a t i s t i c s were performed w i t h BMDP S t a t i s t i c a l Software Inc. (1983). The f o l l o w i n g programs were used: 1) BMDP1D, Simple Data D e s c r i p t i o n and Data Management, f o r data summaries, 2) BMDP5D, Histogram and U n i v a r i a t e P l o t s , f o r g r a p h i c a l summaries of data, 3) BMDP6D, B i v a r i a t e (Scatter) P l o t s , f o r simple l i n e a r c o r r e l a t i o n , 4) BMDP2R, Stepwise Regression, f o r stepwise m u l t i p l e c o r r e l a t i o n , and 5) BMDP9R, A l l P o s s i b l e Subsets Regression. 42 6. RESULTS A. FLORA In 1985, 59 v a s c u l a r p l a n t species, 42 Genera, and 16 F a m i l i e s were recorded i n 142 quadrats (Appendix 2) . In 1986, 40 species, 31 Genera and 13 F a m i l i e s were recorded i n 88 quadrats. Common p l a n t a i n (Plantago major), s m a l l - l e a v e d e v e r l a s t i n g (Antennaria p a r v i f l o r a ) and si l v e r w e e d were the only new species recorded i n 1986. Seven seeded species were recorded on the i s l a n d s , i n c l u d i n g c r e s t e d wheatgrass (Agropyron cristatum) , t a l l wheatgrass (Agropyron elongatum), intermediate wheatgrass (Agropyron intermedium), creeping red fescue (Festuca rubra), smooth brome grass (Bromus inermis), a l f a l f a (Medicago sativa) , and yellow sweet c l o v e r (Melilotus officinalis) . A l s i k e c l o v e r (Trifolium hybridum) was seeded but not recorded. Gramineae i s the r i c h e s t Family i n terms of speci e s . Seventeen and 12 grass species were recorded i n 1985 and 1986, r e s p e c t i v e l y (Appendix 2) . The Compositae and Cyperaceae ranked second and t h i r d i n both years. Twelve composites and 7 c y p e r i n i d s were recorded i n 1985; 7 and 6 were recorded i n 1986. Sow t h i s t l e (Sonchus uliginosus) was recorded i n 70% (99/142) of the quadrats i n 1985. S i x other species were recorded i n more than 45% of the quadrats: t a l l wheatgrass, intermediate wheatgrass, smooth brome grass, Canada t h i s t l e , f o x t a i l b a r l e y (Hordeum jubatum), and yellow sweet c l o v e r . T a l l wheat grass was the most (62%) f r e q u e n t l y recorded species i n 1986, fo l l o w e d by sow t h i s t l e , Canada t h i s t l e , f o x t a i l b a r l e y , smooth brome grass, and red fescue. The l a s t 5 species were recorded i n at l e a s t 45% of the p l o t s . Table 6.1 presents the o v e r a l l frequency r e s u l t s , and Appendix 3 presents the frequency r e s u l t s by i s l a n d . Table 6.1 Frequency 3 of p l a n t species recorded w i t h i n quadrats i n 1985 and 1986. Pl a n t Species 1985 1986 A l f a l f a 15% (19/130) 6% (5/80) Canada t h i s t l e 48% (69/142) 52% (46/88) Creeping red fescue 41% (53/130) 46% (37/80) Crested wheatgrass 16% (21/130) 16% (13/80) F o x t a i l b a r l e y 51% (72/142) 51% (45/88) Intermediate wheatgrass 59% (19/32) 42% (10/24) S a l t meadow grass 28% (40/142) 34% (30/88) Sedge species* 3 20% (29/142) 22% (19/88) Smooth brome grass 46% (66/142) 46% (41/88) Sow t h i s t l e 70% (99/142) 54% (48/88) T a l l wheatgrass 64% (71/110) 62% (40/64) Whitetop grass 34% (49/142) 20% (18/88) Yellow sweet c l o v e r 53% (75/142) 41% (36/88) Percent frequency (No. of quadrats where species was r e c o r d e d / t o t a l no. of quadrats). Carex atherod.es and C. rostrata. Yellow sweet c l o v e r had the greatest mean f o l i a r cover (12.6%) i n 1985 (for I s l a n d No. 1 i n each wetland o n l y ) , f o l l o w e d by sow t h i s t l e , t a l l wheat grass, and Canada t h i s t l e (Table 6.2). In 1986, t a l l wheat grass had the gre a t e s t f o l i a r cover (9.6%), and Canada t h i s t l e and sow t h i s t l e ranked second and t h i r d . Yellow sweet c l o v e r was f o u r t h i n coverage. Nine species ranked i n the top ten f o r f o l i a r cover i n both 1985 and 1986. 44 Islands No. 2, s t u d i e d i n 1985 only, shared w i t h I s l a n d s No. 1, 8 of the 10 species w i t h the g r e a t e s t cover. Whitetop grass had the greatest mean cover (8.6%). Because Islands No. 2 were not s t u d i e d i n 1986, the data from Islands Nos. 1 and 2 i n 1985 were not composited. Table 6.2 F o l i a r cover (%) f o r p l a n t species recorded w i t h the p o i n t - i n t e r c e p t method i n 1985 and 198 6.a P l a n t Species 1985 1986 I s l a n d 1 I s l a n d 2 I s l a n d 1 A l f a l f a 1.4 0.2 0.1 Canada t h i s t l e 4.7 1.7 9.1 Creeping red fescue 3.0 0.6 4.0 Crested wheatgrass 1.6 0.3 0.5 F o x t a i l b a r l e y 3.0 5.0 5.8 Intermediate wheatgrass 1.1 7.0 1.0 S a l t meadow grass 0.6 0.6 1.2 Sedge species 2.2 2.0 1.2 Smooth brome grass 2.4 1.1 1.9 Sow t h i s t l e 6.8 4.6 7.7 T a l l wheatgrass 5.1 6.6 9.6 Whitetop grass 3.5 8.6 2.5 Yellow sweet c l o v e r 12.6 2.0 6.6 The values presented are averages from the 12 wetlands i n 1985 and 11 i n 1986. Of the e i g h t seeded species, a l f a l f a and c r e s t e d wheat-grass were the l e a s t s u c c e s s f u l i n terms of both frequency and f o l i a r cover (Tables 6.1 and 6.2). A l s i k e c l o v e r was not recorded; however, i t was only p l a n t e d at Kingston Slough (Appendix 1). Creeping red fescue and smooth brome grass were f r e q u e n t l y recorded, but they seldom c o n t r i b u t e d s u b s t a n t i a l l y to f o l i a r cover. T a l l wheatgrass and yellow 45 sweet c l o v e r were the most frequent species and c o n t r i b u t e d the most to the cover. Nonseeded species w i t h c o n s i s t e n t l y high coverage and frequency i n c l u d e d sow t h i s t l e , Canada t h i s t l e , whitetop, f o x t a i l b a r l e y , and sedge spp. Table 6.3 l i s t s the dominant species, by f o l i a r cover, recorded on each i s l a n d i n 1985. and 1986 . Table 6.3. Species dominant and subdominant, i n terms of f o l i a r cover, on wetland i s l a n d s i n 1985 and 1986. Wetland Species B u t t e r Lake 1 Hebert Lake 1 Houcher F l a t 1 Houcher Lake 1 Kingston 1 Slough Louis Lake Sow t h i s t l e , Canada t h i s t l e , y e llow sweet c l o v e r (1985) a Sow t h i s t l e , sedges T a l l wheatgrass, f o x t a i l b a r l e y , & yellow sweet c l o v e r T a l l wheatgrass, & yellow sweet c l o v e r F o x t a i l b a r l e y , whitetop (1985), Canada t h i s t l e (1986) F o x t a i l b a r l e y , whitetop, Fremont's goosefoot (Chenopodium fremontii) Whitetop, yellow sweet c l o v e r , & Canada t h i s t l e (sub) Whitetop Intermediate wheatgrass, f o x t a i l b a r l e y , s a l t meadow grass & sow t h i s t l e Intermediate wheatgrass, & f o x t a i l b a r l e y Sow t h i s t l e , mint, yellow sweet c l o v e r (1985 sub) & Canada t h i s t l e (1986 sub) 46 Table 6.3. continued. Wetland Species Marstrand Project. Sow t h i s t l e , Canada t h i s t l e , smooth brome grass (sub), t a l l wheatgrass (sub) Paulgaard Marsh 1 & 2 T a l l wheatgrass Reta P r o j e c t Sedge (Carex atherodes), sow t h i s t l e , Canada t h i s t l e & reed grass (Calamagrostis stricta) R o l l y v i e w Marsh 1& 2 T a l l wheatgrass and oak-leaved goosefoot (Chenopodium salinum) Waskwei Creek Creeping red fescue, smooth brome grass, sedge (C. atherodes), & c r e s t e d wheatgrass Z i l k e Marsh Yellow sweet c l o v e r , & creeping red fescue (sub) I n d i c a t e s the one year when the species was predominant, or i n d i c a t e s a subdominant species (sub). B. TOTAL FOLIAR, NESTINGBOARD, LITTER AND SOIL COVER FOR EACH WETLAND In 1985, i s l a n d f o l i a r cover ranged from 15% at Ro l l y v i e w Marsh I s l a n d No. 1 to 89% at Louis l a k e . In 1986, f o l i a r cover v a r i e d from 16% at R o l l y v i e w Marsh to 84% at Louis Lake. Table 6.4 presents i s l a n d f o l i a r cover and nestingboard cover values f o r i n d i v i d u a l wetlands. In 1985, Louis Lake, Waskwei Creek, and Bu t t e r Lake i s l a n d s had the highest f o l i a r and nestingboard cover. Kingston Slough, R o l l y v i e w Marsh and Marstrand P r o j e c t had the poorest cover. In 198 6, f o l i a r and nestingboard cover peaked at Louis Lake, 47 B u t t e r Lake, Houcher Lake, and Z i l k e Marsh; Kingston Slough and R o l l y v i e w Marsh had the poorest cover. Table 6.5 breaks down i s l a n d f o l i a r cover i n t o seeded and nonseeded species components f o r each wetland. In 1985 and 1986, seeded species dominated the v e g e t a t i o n on Hebert Lake, Paulgaard Marsh, Waskwei Creek, and Z i l k e Lake. In 1986, the R o l l y v i e w Marsh ve g e t a t i o n was comprised of seeded species p r i m a r i l y . B u t t e r Lake, Houcher F l a t and Lake, Kingston Slough, Louis Lake, and Marstrand and Reta P r o j e c t s were dominated by nonseeded spec i e s . Table 6.4 Mean f o l i a r coyer (%), measured w i t h the p o i n t i n t e r c e p t method, i n 1985 and 1986. Nestingboard values (%) are bracketed. Wetland 1985 1986 I s l a n d 1 I s l a n d 2 , I s l a n d 1 Bu t t e r Lake 77 .3 (90. 4) 52 .3 (59. 5) 63 .5 (71 .1) Hebert Lake 33 .3 (42. 3) 27 .7 (32. 7) 41 .8 (52 .2) Houcher F l a t 47 .7 (41. 3) 61 .0 (65. 1) 51 .0 (26 .0) Houcher Lake 68 .7 (67. 9) 50 .7 (63. 6) 78 .4 (94 .5) Kingston Slough 15 .7 ( 3. 6) 14 .3 (6. 1) 17 .2 (5 .4) Louis Lake 89 .0 (84. 9) NS a 83 .9 (95 .2) Marstrand P r o j e c t 28 .3 (20. 5) NS 44 .5 (32 .0) Paulgaard Marsh 45 .0 (48 . 9) 33 .3 (48. 1) 62 .2 (69 .4) Reta P r o j e c t 45 .7 (30. 4) 37 .7 (22. 5) NS R o l l y v i e w Marsh 15 .0 (0. 8) 40 .0 (15. 7) 15 .8 (7 .1) Waskwei Creek 73 .3 (91. 6) NS 42 .5 (25 .5) Z i l k e Marsh 71 .3 (39. 3) NS 68 .0 (65 .6) Annual Mean 50 .5 (48 .9) 51 .7 (49 .5) a NS - i s l a n d not sampled. In 198 5 only one i s l a n d was sampled i n some wetlands. In 1986, Reta P r o j e c t was dropped from the study. 48 Table 6.5 Mean f o l i a r cover (%) of seeded and nonseeded (in brackets) vegetation i n 1985 and 1986. Wetland 1985 1986 Island 1 Island 2 Island 1 Butter Lake 34 . 2 (43. 3) 4, .0 (48. .3) 0 . 8 (62. .8) Hebert Lake 25, . 6 (7. 8) 25, .0 (2, .8) 27 , . 9 (13, .8) Houcher F l a t 2. .8 (45. 0) 2. .3 (58 , .9) 4. .6 (46. .6) Houcher Lake 22. .5 (46. 2) 0, . 6 (50 , .0) 21. .5 (55, .6) Kingston Slough 4 , .0 (11. 7) 9, .4 (5, .0) 3. .8 (13. • 4) Louis Lake 15. .0 (74. 0) NSa 3. .8 (80. .1) Marstrand Project 5. .0 (23. 3) NS 8. .8 (37. .0) Paulgaard Marsh 37. .2 (7. 8) 22. .8 (10. .6) 50. .8 (11. .1) Reta Project 6, .7 (38. 9) 2. .3 (35. .6) NS Rollyview Marsh 4. .4 (10. 6) 10, .6 (29. .4) 11. .2 (4. .5) Waskwei Creek 55, .0 (18 . 3) NS 34. . 6 (7. .9) Zilke Marsh 68, .7 . (2. 7) NS 51. .8 (16. .1) Annual Mean • 21 .6 (28. .9) 19. ,9 (31. •7) NS - i s l a n d not sampled. In 1986, a l l h i t s were c l a s s i f i e d as plant cover, l i t t e r , s o i l or bryophyte (Table 6.6). L i t t e r cover averaged from 7% at Rollyview Marsh to 57% at Waskwei Creek. S o i l exposure was maximal at Rollyview Marsh (77%) , and lowest at Butter Lake, Houcher Lake, Louis Lake, and Waskwei Creek, a l l with 1%. 49 Table 6.6 Mean (%) and range (%) of l i t t e r , s o i l and bryophyte cover at each wetland i n 1986. Wetland S o i l L i t t e r Bryophytes B u t t e r Lake 1 (0- 10) 35 (13- -57) 0 Hebert Lake 28 (0- 87) 28 (3--50) 2 (0- 13) Houcher F l a t 22 (0- 60) 26 (3--57) 0 Houcher Lake 1 (0 -3) 21 (13- -33) 0 Kingston Slough 65 (50- 87) 16 (10- -23) 1 (0. -7) Louis Lake 1 (0 -7) 15 (3--27) 0 Marstrand P r o j e c t 25 (0- 50) 28 (17- -43) 1 (0 -7) Paulgaard Marsh 10 (0- 73) 26 (0--47) 2 (0 -7) R o l l y v i e w Marsh 77 (60- 97) 7 (0--23) 0 Waskwei Creek 1 (0 -3) 57 (47- -77) 0 Z i l k e Marsh 2 (0- 10) 30 (17- -47) <1 (0 -3) C. ISLAND SOIL AND SITE CONDITIONS S o i l Chemical Conditions In 1985 and 1986, s o i l effervescence at Paulgaard Marsh, Louis Lake and, t o a l e s s e r degree, Z i l k e Marsh, was moderately strong t o strong. S o i l effervescence was absent or very weak at Reta P r o j e c t , Houcher F l a t and Lake, and Waskwei Creek. The remaining i s l a n d s were e i t h e r weak, or v a r i e d between years. E l e c t r i c a l c o n d u c t i v i t y (EC), when measured on a water e x t r a c t , averaged 2.5 dS/m (Standard E r r o r (SE) = 0.1, Range = 0.4 - 5.4) i n 1985 and 2.4 dS/m (SE = 0.2, Range = 0.5 -5.2) in. 1986 (Table 6.7). Houcher F l a t and Lake, and Ro l l y v i e w Marsh I s l a n d No. 2 s o i l s measured greater than 4.0 dS/m i n 1985 and 1986. EC, measured on a sa t u r a t e d paste i n 1986, averaged 3.4 dS/m (SE = 0.3; Range = 0.8 - 5.0). 50 Houcher Lake and Kingston Slough had the highest l e v e l s , Hebert Lake s o i l s the lowest. Table 6.7 E l e c t r i c a l c o n d u c t i v i t y (dS/m) of i s l a n d s o i l s i n 1985 and 1986. Wetland 1:2 Soil-Water E x t r a c t Saturated Paste 1985 1986 1986 Bu t t e r Lake 1 2.3 1.2 2.6 Bu t t e r Lake 2 _a - -Hebert Lake 1 0.7 0.5 0.8 Hebert Lake 2 0.7 - -Houcher F l a t 1 4.1 5.2 -Houcher F l a t 2 - - -Houcher Lake 1 3.7 4.8 5.0 Houcher Lake 2 - - • -Kingston Slough 1 2.8 2.6 4.6 Kingston Slough 2 2.7 - -Louis Lake 2.9 3.0 3.4 Marstrand P r o j e c t 3.0 1.8 3.6 Paulgaard Marsh 1 1.6 1.2 • 2.5 Paulgaard Marsh 2 2.0 - -Reta P r o j e c t 1 0.4 - -Reta P r o j e c t 2 0.7 - -R o l l y v i e w Marsh 1 1.9 2.2 '2.4 Ro l l y v i e w Marsh 2 5.4 - -Waskwei Creek 2.3 1.8 3.0 Z i l k e Marsh 3.3 2.6 3.6 Annual Mean 2.5 2.4 3.4 S o i l samples not analyzed or i s l a n d s not sampled. Exchangeable calcium (Ca) averaged 11.2 cmol/kg (SE = 0.5, Range = 5.6 - 19.2) and 12.7 cmol/kg (SE = 0.9, Range = 5.7 - 23.0) i n 1985 and 1986, r e s p e c t i v e l y (Table 6.8). Hebert Lake, Kingston Slough, Reta P r o j e c t , and R o l l y v i e w Marsh s o i l s were r e l a t i v e l y low i n exchangeable Ca, whereas Houcher Lake and F l a t and Louis Lake had r e l a t i v e l y high l e v e l s . 51 Table 6.8 Exchangeable (cmol/kg) and s o l u b l e (me/L) c a t i o n l e v e l s of i s l a n d s o i l s i n 1985 and 1986. Wetland Cation Exchangeable Cations Soluble Cations 1985 1986 1986 Islands I s l a n d I s l a n d 1 2 1 1 Houcher Lake Ca 11. .6 - a 11. .0 13. .8 Mg 3. .0 -— 3. .0 6. . 9 Na 2. .4 -— 1. .7 6. .3 K 1. .2 -— 1. .7 2. .5 Hebert Lake Ca 5. . 6 ' 7 .9 6, .0 0. .2 Mg 1, .2 1 .2 1. .4 0. .5 Na 5. .5 5 .0 5. .8 5. . 9 K 0. .8 0 .8 1. .0 1. .0 Houcher F l a t Ca 15. .4 -— — - — — -— Mg 7 , .2 -— --— --— Na 7. . 6 -— --— --— K 1, . 9 — — — — — — Houcher Lake Ca 19. .2 — — 23. .0 15. . 6 Mg 6. .2 -— 7. . 4 10. . 1 Na 8, .1 -— 11. .8 32. . 6 K 2, .2 — — 2. .5 1. .7 Kingston Slough Ca 7 . 5 -— 8 . 7 1. .2 Mg 2 , .5 -— 2. .8 1. . 6 Na 13 .5 -— 13. .5 50. .2 K 1, .1 — — 1. .3 0. .8 Louis Lake Ca 16, .4 — — 23. .0 24 . 5 Mg 3. .2 -— 4 . 2 11. . 6 Na 1. . 9 - -- 1 . 3 5. .3 K 0. .3 -— 0. .5 0. . 6 Marstrand Ca 12. . 6 — — 11. .1 11. .5 Mg : 3. 2 -— 3. .2 5. .4 Na 5. . 6 --- 4 . 5 20. . 6 K 1. .7 — — 1. . 9 1. . 6 Paulgaard Marsh Ca 10. .1 -— 8. .8 0. .7 Mg 3. . 6 -— 3. .8 0 . 8 Na 5. .8 - -- . 5. .8 •21. .0 K 1, .0 --- 1. .2 1. .1 52 Table 6.8 continued. Wetland Cation Exchangeable Cations Soluble Cations 1985 1986 1986 Islands I s l a n d I s l a n d 1 2 1 1 Reta P r o j e c t Ca 6.8 9.3 — _ _ Mg 2.7 2.2 Na 4 . 8 4.2 K 1-1 0.4 R o l l y v i e w Marsh Ca 7.2 5.7 0.3 Mg 2.2 3.0 0.5 Na 11.4 14.1 21.0 K 0.8 1.3 0.6 Waskwei Creek Ca 9.0 9.6 14 .2 Mg 3.2 3.6 7.7 Na 3.2 3.1 11.0 K 1. 6 • 2.2 2.2 Z i l k e Marsh Ca 14.8 20.1 23.1 Mg 4.7 5.4 15. 9 Na 1.9 1.2 5.8 K 1.0 1.3 2. 0 Annual Mean Ca 11. 2 12.7 12.1 Mg 3. 4 3.8 7.0 Na 5. 9 6 . 4 18 . 8 K 1. 2 1.5 1.5 I s l a n d not sampled or s o i l samples not analysed. 53 In 1986, s o l u b l e Ca (SCa) averaged 12.1 me/L (SE =1.9, Range = 0.2 - 24.5). Wetlands with high SCa l e v e l s i n c l u d e d Louis Lake and Z i l k e Marsh, whereas wetlands w i t h low l e v e l s i n c l u d e d Hebert Lake, Kingston Slough, Paulgaard Marsh and R o l l y v i e w Marsh (Table 6.8). Exchangeable Mg averaged 3.4 cmol/kg (SE = 0.2, Range = 1.2 - 7.2) i n 1985 and 3.8 cmol/kg (SE = 0.2, Range = 1.4 -7.4) i n 1986 (Table 6.8). R e l a t i v e l y high l e v e l s were measured i n s o i l s from Houcher F l a t and Lake, and Z i l k e Marsh. Hebert Lake i s l a n d s o i l s were low i n Mg. Mean s o l u b l e Mg (SMg) was 7.0 me/L (SE = 1.2, Range = 0.5 - 15.9) i n 1986 (Table 6.8). Houcher Lake, Louis Lake and Z i l k e Marsh i s l a n d s ranked high i n SMg, whereas Hebert Lake, Kingston Slough, Paulgaard Marsh, and R o l l y v i e w Marsh ranked low. Exchangeable Na averaged 5.9 cmol/kg (SE = 0.4, Range = 1.9 - 13.5) i n 1985 and 6.4 cmol/kg (SE = 0.6, Range = 1.2 -14.1) i n 1986 (Table 6.8). R o l l y v i e w Marsh and Kingston Slough had p a r t i c u l a r l y high Na l e v e l s i n both years. Houcher F l a t and Lake i s l a n d s were moderately high. Wetlands w i t h low Na l e v e l s i n c l u d e d B u t t e r Lake, Louis Lake, and Z i l k e Marsh. Soluble Na (SNa) averaged 18.8 me/L (SE = 3.9, Range = 5.3 - 50.2 me/L) i n 1986 (Table 6.8). Only Kingston Slough and, to a l e s s e r degree, Houcher Lake s o i l s were p a r t i c u l a r l y high i n t h i s property. B u t t e r Lake, Hebert 54 Lake, Louis Lake, and Z i l k e Marsh a l l had low l e v e l s of s o l u b l e Na. The sodium adsorption r a t i o (SAR) averaged 12.7 (SE = 3.3, Range = 1.2: - 42.4) i n 1986 (Table 6.9). Three wetlands had i s l a n d s o i l s w i t h a SAR w e l l above the recommended maximum of 12 f o r p l a n t growth: Kingston Slough, Paulgaard Marsh, and R o l l y v i e w Marsh. Four wetlands were below 5: Bu t t e r Lake, Louis Lake, Waskwei Creek, and Z i l k e Marsh. Exchangeable sodium percentage (ESP) averaged 19.0% i n 1986 (Table 6.9). Four wetlands had e x c e s s i v e l y high ESP l e v e l s (> 50%) : Hebert Lake, Kingston Slough, Paulgaard Marsh and R o l l y v i e w Marsh. Except f o r Houcher Lake, which had an ESP of 18.9%, the remaining wetlands l e v e l s were below 10%. In 1985, mean exchangeable potassium was 1.2 cmol/kg (SE = 0.1, Range = 0.3 - 2.2); i n 1986, i t was 1.5 cmol/kg (SE = 0.1, Range = 0.5 - 2.5). Houcher F l a t and Lake, Marstrand P r o j e c t and Waskwei Creek i s l a n d s a l l had high l e v e l s of exchangeable K; Hebert and Louis Lakes had low l e v e l s of t h i s n u t r i e n t (Table 6.8). The s o l u b l e form of K (SK) averaged 1.5 me/L (SE = 0.2, Range = 0.6 - 2.5) i n 1986 (Table 6.8). Again Hebert and Louis Lakes were low i n K, as were Kingston Slough and R o l l y v i e w Marsh. B u t t e r Lake, Waskwei Creek and Z i l k e Marsh l e v e l s were r e l a t i v e l y high. 55 Table 6.9 Mean sodium adsorption r a t i o s (SAR), exchange-able sodium percentage (ESP), c a t i o n exchange c a p a c i t y (CEC), and phosphorus l e v e l s of i s l a n d s o i l s . SAR, ESP and CEC were measured i n 1986, whereas P was measured i n 1985. Wetland SAR ESP CEC P (cmol/kg) (ppm) B u t t e r Lake 2.1 8.3 20.6 9.8 Hebert Lake 10.3 54 .2 10.7 12.5 a Houcher F l a t b 87.5 Houcher Lake 9.0 18.9 62.2 22.1 Kingston Slough 42.4 67.4 20.0 11.2 Louis Lake 1.2 3.3 40.2 19.5 Marstrand P r o j e c t 7.9 1.2 36.3 15. 6 Paulgaard Marsh 28.8 65.0 8.8 13.3 Reta P r o j e c t 9.8 R o l l y v i e w Marsh 32.0 89.0 15.8 11.2 Waskwei Creek 3.7 7.7 40.2 9.2 Z i l k e Marsh 1.3 4.4 28.3 5.1 Annual Mean 12.7 19.0 30.6 18 . 9 Sample from I s l a n d 2, a l l others from I s l a n d 1. S o i l s not analysed. The c a t i o n exchange c a p a c i t y (CEC), measured i n 1986, averaged 30.6 cmol/kg (SE = 3.3, Range = 8 . 8 - 6 2 . 2 ) . Houcher Lake s o i l s had a high CEC, while Hebert Lake and Paulgaard Marsh l e v e l s were very low (Table 6.9). Mean s o i l P was 18.9 ppm (SE = 5.4, Range = 5.1 - 87.5) i n 1985. The P l e v e l was extremely high on Houcher Lake (87.5 ppm) . B u t t e r Lake, Reta P r o j e c t , Waskwei Creek, and Z i l k e Marsh l e v e l s were a l l below 10.0 ppm (Table 6.9). Mean s o i l pH, when measured i n water (pH w) , was 7.4 (SE = 0.1, Range = 6.2 - 8.7) i n 1985 and 8.1 (SE = 0.1, Range = 6.3 - 9.5) i n 1986. S o i l pH w was p a r t i c u l a r l y high 56 at Hebert Lake, Kingston Slough, Paulgaard Marsh, and R o l l y v i e w Marsh. In both years, Waskwei Creek had the lowest pH w (Table 6.10). S o i l pH i n C a C l 2 (pH c) averaged 6.6 (SE = 0.04, Range = 5 . 7 - 7 . 5 ) i n 1985 and 7.6 (SE = 0.1, Range = 6.0 - 8.6) i n 1986. In 1985, pH c v a r i e d l i t t l e from n e u t r a l (pH c = 7.0) or from wetland to wetland: 5.7 at Waskwei Creek t o 7.5 at Kingston I s l a n d 2. The 1986 r e s u l t s were s i m i l a r to the pH w data. Kingston Slough, Paulgaard Marsh and R o l l y v i e w Marsh were again high, whereas Waskwei Creek was the lowest (Table 6.10) . In 1985, organic C averaged 3.0% (SE = 0.3, Range = 0.3 - 14.4). In 1986, i t averaged 3.4% (SE = 0.4, Range = 0.3 - 12.9) . ' Louis Lake s o i l s were very high (> 12%) i n C; Hebert Lake, Kingston Slough, and R o l l y v i e w Marsh l e v e l s were low (<1%) . S o i l N averaged 0.24% (SE =0.03, Range = 0.03 - 1.00) i n 1985 and 0.29% (SE = 0.1, Range = 0.02 - 1.07) i n 1986. As w i t h C, s o i l N was greatest at Louis Lake (~1%) and lowest at Hebert Lake, Kingston Slough, and R o l l y v i e w Marsh (< 0.05%) (Table 6.10). 57 Table 6.10 S o i l pH, organic carbon (%) and t o t a l n i t r o g e n (%) l e v e l s averaged by i s l a n d and year. Wetland S o i l 1985 1986 Property Islands I s l a n d B u t t e r Lake P Hw (PH C) . 6. 9 (6 3) 7. 0 (6 5) 7 8 (7 .4) C (N) 1 1 (0 10) 1. 7 [ — -) 1 2 (0 .08) Hebert Lake pH w (PH C) 8 6 (6 8) 8. 6 (6 7) 9 4 (7 .8) C (N) 0 3 (0 03) 0. 3 (0 03) 0 3 (0 .02) Houcher F l a t pH w (PH C) 6 7 (6 8) 6. 8 (6 3) 7 2 (7 .3) C (N) 3 3 (0 25) 5. 6 [ —---) — -— [ — — ) Houcher Lake P Hw (PH C) 6 9 (6 .6) 6. 8 (6 .5) 7 5 (7 .3) C (N) 3 6 (0 .30) 3. 5 [ — ---) 5 0 (0 .32) Kingston Slough PH W (PH C) 8 3 (7 .2) 8. 5 (7 5) 9 2 (8 .3) C (N) 0 6 (0 .05) 0. 5 [ — --) 0 6 (0 .04) Louis Lake P Hw (PH C) 6 5 (6 .6) — - [ ----) 7 . 6 (7 .6) C (N) 14 4 (1 .00) — — [ — --) 12 . 9 (1 .07) Marstrand P Hw (PH C) 7 1 (6 .6) — — [ —-- ) 7 .7 (7 • 2) C (N) 2 7 (0 .24) — — [ — --) 2 . 1 (0 .10) Paulgaard Marsh PH W (PH C) 8 1 (7 .0) 8. 4 (7 .1) 9 .5 (8 .4) C (N) 1 2 (0 .12) 1. 5 [ — --) 1 5 (0 .08) Reta P r o j e c t PH W (PHC) 6 8 (6 .2) 7 . 7 (6 .5) ---- [ -— ) C (N) 3 2 (0 .25) 2. 8 (0 .22) — — [ — — ) R o l l y v i e w Marsh PH W (PH C) 8 7 (7 .2) 8. 1 (7 .3) 9 .4 (8 • 6) C (N) 0 4 (0 .05 ) 2. 1 [ — --) 0 .7 (0 .04) Waskwei Creek P Hw (PH C) 6 2 (5 .7) — - [ ----) 6 .3 (6 .0) C (N) 5 3 (0 .42) — — [ —---) 5 .2 (0 .43) Z i l k e Marsh P Hw (PHC) 6 6 (6 .6) — — [ —-- ) 7 7 (7 .6) C (N) 2 7 (0 .24) — — [ — --) 4 .4 (0 .38) Annual Mean P Hw (PH C) 7.4(6 .6) 8 . 1 (7 .6) C (N) 3.0(0 .24) 3 .4 (0 .29) 58 S o i l Physical Conditions Bulk d e n s i t y averaged 1048 kg/m3 (SE = 33, Range = 338 - 1537) i n 1985 and 1138 kg/m3 (SE = 47, Range = 514 - 1599) i n 1986. Bulk d e n s i t y was lowest at Louis Lake (< 500 kg/m3) and highest at Hebert Lake, Kingston Slough, and Paulgaard and R o l l y v i e w Marshes (> 1400 kg/m3) (Table 6.11). Table 6.11 Mean bulk d e n s i t y (kg/m-3) f o r i s l a n d s sampled i n 1985 and 1986. Wetland 1985 1986 I s l a n d 1 I s l a n d 2 I s l a n d 1 B u t t e r Lake 838 1128 1460 Hebert Lake 1481 1381 1501 Houcher F l a t 679 692 723 Houcher Lake 619 750 596 Kingston Slough 1485 1537 1571 Louis Lake 338 a 514 Marstrand P r o j e c t 1143 — 1074 Paulgaard Marsh 1253 1396 1469 Reta P r o j e c t ' 924 1394 --R o l l y v i e w Marsh 1498 1182 1599 Waskwei Creek 998 — 971 Z i l k e Marsh 942 — 1041 Annual Mean 1048 1138 Islands not sampled. In 1985, the c l a y f r a c t i o n averaged 32.1% (SE = 4.1, Range = 12.8 - 7 6.4) . At Houcher Lake and F l a t c l a y accounted f o r greater than 70% by mass. Clay comprised l e s s than 17% of the s o i l at Hebert Lake, Paulgaard Marsh, and Reta P r o j e c t (Table 6.12). 59 In 1986, t o t a l p o r o s i t y averaged 59.2%, ranging from 49.0 t o 77.3 (SE = 2.9). T o t a l p o r o s i t y was gr e a t e s t at Houcher and Louis Lake (> 75%) and lowest at B u t t e r Lake and Kingston Marsh (< 50%). A e r a t i o n p o r o s i t y averaged 11.1% (SE = 0.8, Range = 5 . 4 - 1 8 . 9 ) of the t o t a l volume i n 1986. A e r a t i o n p o r o s i t y was lowest at Kingston Slough where i t was 5.4%, and gr e a t e s t at Louis Lake at 18.9% (Table 6.12). Table 6.12 T o t a l p o r o s i t y and a e r a t i o n p o r o s i t y , expressed as a percentage of the t o t a l volume, and percent c l a y of i s l a n d s o i l s . P o r o s i t y was measured i n 1986, whereas c l a y was measured i n 1985. T o t a l A e r a t i o n Wetland P o r o s i t y P o r o s i t y Clay (%) (%) (%) B u t t e r Lake 49.0 11.0 34.6 Hebert Lake a — 16.8 Houcher F l a t — — 74.0 Houcher Lake 75.7 12.3 76.4 Kingston Slough 47.3 5.4 23.2 Louis Lake 77.3 18 . 9 — Marstrand P r o j e c t 56.7 13.0 36.0 Paulgaard Marsh 51.0 10.2 12 .8 Reta P r o j e c t — — 14.0 R o l l y v i e w Marsh — — 26.4 Waskwei Creek 57.7 8.1 41.0 Z i l k e Marsh — — 32.4 Annual Mean 59.2 11.1 32.1 a Islands not sampled. Steady-state i n f i l t r a t i o n was 64.8 cm/h (SE = 18.1, Range = < 0.1 - 730.7) i n 198 ;5 and 13.0 cm/h (SE = 3.4, Range = < 0.1 - 63.8) i n 1986 (Table 6.13). Houcher i s l a n d s e x h i b i t e d greater i n f i l t r i b i l i t y than other wetlands i n 1985 60 and 1986. Louis Lake s o i l had a high rate i n 1986. Hebert Lake, Kingston Slough, and Rollyview Marsh had low i n f i l t r i b i l i t y (most < 1 cm/h) i n both years. Median i n f i l t r a t i o n rates were calculated for each quadrat only i n 1985, because the difference between the mean and median values was small (Median = 50.4 cm/h, SE = 16.4, Range = < 0.1 - 647.1 cm/h). Table 6.13 Average steady-state i n f i l t r a t i o n , rates (cm/h) for 1985 and 1986. Wetland 1985 1986 Island 1 • Island 2 Island 1 Butter Lake 42.1 30.4 3.3 Hebert Lake 5.8 5.7 0.1 Houcher F l a t 127.2 730.7 25.8 Houcher Lake 64.2 27 .5 63.8 Kingston Slough 0.2 <0.1 <0 .1 Louis Lake 61.3 a 27 . 9 Marstrand Project 22.0 — 7-. 9 Paulgaard Marsh 19.8 21.2 8.0 Reta Project 125.7 5. 6 --Rollyview Marsh <0.1 0.2 0.1 Waskwei Creek 60.6 — 0.5 Zilke Marsh 30.2 — 5.4 Annual Mean 64. 8 13.0 Islands not sampled. 61 S i t e C h a r a c t e r i s t i c s The average slope of quadrat s i t e s was 3.9° (SE = 0.3, Range =0.0 -16.0) i n 1985 and 4.3° (SE = 0.3, Range = 0.0 -13.0) i n 1986. In 1985, Reta I s l a n d No. 1 had the lowest mean slope of 0 . 3 ° , whereas Hebert Lake I s l a n d No. 2 had the gr e a t e s t w i t h 8 . 7 ° . In 1986, Kingston Slough had the gr e a t e s t slope (7.6°), whereas B u t t e r Lake and Waskwei Creek had the lowest (2.0°). Most quadrats had an aspect of e i t h e r northwest or east. Northeast and west aspects were a l s o f a i r l y common. Although quadrats occurred i n a l l s e c t i o n s on most i s l a n d s , quadrats tended t o be l o c a t e d i n the upper slope p o s i t i o n and s e c o n d a r i l y i n the middle slope, even though placement was random. The microtopography at each quadrat was u s u a l l y smooth or s l i g h t l y mounded. A few s i t e s i n both years were r a t e d as moderately or s t r o n g l y mounded. Drainage was estimated to be moderately w e l l to w e l l d rained at most s i t e s , although there were s i t e s considered to be r a p i d l y or p o o r l y drained. Quadrat height averaged 0.66 m (SE = 0.02, Range = 0.23 - 1.37) i n 1985 and 0.52 m (SE = 0.02, Range = 0.10 -1.07) above water i n 1986. In 1985, Z i l k e Marsh s i t e s averaged 0.96 m above water, while Houcher F l a t I s l a n d No. 2 averaged only 0.52 m. Marstrand P r o j e c t had the g r e a t e s t average height i n 1986, at 0.80 m, and Hebert Lake was lowest at 0.27 m. 62 D. IMPACT OF WEATHER AND ISLAND AGE ON PLANT COVER In 1985, t o t a l and seeded f o l i a r , and nestingboard cover were compared t o the number of days w i t h measurable-r a i n f a l l and the t o t a l r a i n f a l l d uring the f i r s t growing season. Cover was a l s o compared t o the t o t a l cumulative growing degree days (GDD) > 0° and > 5°C si n c e seeding. N e i t h e r measure of GDD was c o r r e l a t e d (P > 0.05) w i t h any measure of p l a n t cover. P l a n t cover was a l s o not r e l a t e d to me a s u r a b l e - r a i n f a l l - d a y s i n the f i r s t growing season, i n c l u d i n g the periods A p r i l to October, May to September, and the two months post-seeding. S i m i l a r l y , the e f f e c t of t o t a l r a i n f a l l on p l a n t cover d u r i n g the same periods was not s i g n i f i c a n t . I s l a n d age and the time-since-seeding was not c o r r e l a t e d (P > 0.05) w i t h t o t a l and seeded species f o l i a r and nestingboard cover. E. IMPACT OF SOIL AND SITE CONDITIONS ON TOTAL FOLIAR COVER Simple Linear Correlation Seven v a r i a b l e s were c o r r e l a t e d (P < 0.05) w i t h t o t a l f o l i a r cover i n both 1985 and 1986. N e g a t i v e l y c o r r e l a t e d v a r i a b l e s i n c l u d e BD, pH and exchangeable Na, whereas C, N, and exchangeable Ca and Mg were p o s i t i v e l y c o r r e l a t e d (Table 6.14). (Note.: In the t e x t and t a b l e s , p r e d i c t o r v a r i a b l e s preceded by a negative s i g n i n d i c a t e negative c o r r e l a t i o n s w i t h the response v a r i a b l e s , e.g. -BD.) 63 In 1985, f o l i a r cover was n e g a t i v e l y c o r r e l a t e d with slope, and i n 1986 i t was p o s i t i v e l y c o r r e l a t e d w i t h SCa and SMg, i n f i l t r a t i o n , EC, and t o t a l and a e r a t i o n p o r o s i t y . F o l i a r cover was n e g a t i v e l y c o r r e l a t e d w i t h SAR i n 1986. Table 6.14 S o i l and s i t e v a r i a b l e s c o r r e l a t e d w i t h t o t a l f o l i a r and nestingboard cover (P < 0.05). Response V a r i a b l e Date P r e d i c t o r V a r i a b l e 3 ' * 5 T o t a l f o l i a r cover 1985 & 1986 -BD, -pH w, C, N, Ca, Mg, -Na, -pH c 1985 -slope 1986 EC,- i n f i l , apor, t p o r , SCa, SMg, -SAR Nestingboard cover 1985 & 1986 -BD, -Na, Ca, C, N 1985 -PH W, -pH g 1986 -SNa, i n f i l , t p o r , -SAR, SCa, Mg BD: bulk d e n s i t y ; pH w: pH i n water; pH c: pH i n CaCl2; C: organic carbon; N: t o t a l n i t r o g e n ; Ca, Mg, Na, & K: exchangeable c a t i o n s ; SCa, SMg, SK & SNa: s o l u b l e c a t i o n s ; EC:, e l e c t r i c a l c o n d u c t i v i t y ; i n f i l : mean i n f i l t r a t i o n , ( i n f i l m e d i f median value used); SAR: sodium adsorption r a t i o ; apor: a e r a t i o n p o r o s i t y ; t p o r : t o t a l p o r o s i t y . . Negative signs preceding the p r e d i c t o r v a r i a b l e s i n d i c a t e negative c o r r e l a t i o n s w i t h the response v a r i a b l e . V egetative cover was a l s o recorded u s i n g a n e s t i n g -board. F i v e v a r i a b l e s were c o r r e l a t e d (P < 0.05) with n e s t i n g cover i n both 1985 and 1986: -BD, exchangeable -Na, exchangeable Ca, C, and N. Nesting cover was h i g h l y c o r r e l a t e d (P < 0.001) wit h -pH i n 1985, and i n 1986 was 64 a l s o c o r r e l a t e d (P < 0.05) wi t h exchangeable Mg, i n f i l t r a t i o n , t o t a l p o r o s i t y , -SAR, and SCa and -Na (Table 6.14) . Multiple Linear Correlation M u l t i p l e c o r r e l a t i o n analyses were used t o i d e n t i f y v a r i a b l e s which were c o r r e l a t e d w i t h t o t a l f o l i a r cover. These analyses i d e n t i f i e d three v a r i a b l e s c o n s i s t e n t l y s i g n i f i c a n t i n 1985 and 1986: -pH, -BD, and exchangeable -Na. In 1985, t o t a l N was a l s o important, w h i l e i n 1986 exchangeable Ca was important. In 1985, the strongest c o r r e l a t i o n w i t h f o l i a r cover was achieved w i t h the v a r i a b l e subset comprised of -pH w, BD, and exchangeable -Na (R 2 = 0.64, n = 78), accounting f o r almost t w o - t h i r d s of the data's v a r i a t i o n (Table 6.15). The l a t t e r r e s u l t was achieved using stepwise m u l t i p l e c o r r e l a t i o n . Although higher c o e f f i c i e n t s of determination were achieved (R 2 = 0.67, n = 70) when p r e d i c t o r v a r i a b l e s were l o g a r i t h m i c a l l y transformed, the increase i n R 2 was i n s u f f i c i e n t t o j u s t i f y the incre a s e d d i f f i c u l t y i n understanding. A l l p o s s i b l e combinations (APC) m u l t i p l e c o r r e l a t i o n generated a number of v a r i a b l e subsets f o r the 1985 and 1986 data (Table 6.15). The importance of pH, BD and Na as a determinant of f o l i a r cover i s r e f l e c t e d i n . these subsets. For example, - p H w and -BD were the best s i n g l e v a r i a b l e subsets, and -BD with exchangeable -Na was the best two-v a r i a b l e subset. 65 In 1986, EC, -pH c, -BD, and exchangeable -Na were the important v a r i a b l e s (R 2 = 0.56, n = 80). Stepwise (SW) c o r r e l a t i o n y i e l d e d t h i s , subset from a n a l y s i s of the f u l l data set ( r 2 = 0.56, n = 80) . Using a l l p o s s i b l e combinations c o r r e l a t i o n a n a l y s i s , the best one- through f o u r - v a r i a b l e subsets were determined (Table 6.15). S i m i l a r t o 1985, the v a r i a b l e s -pH, -bulk d e n s i t y and exchangeable -Na f i g u r e prominently i n the v a r i o u s subsets. C o r r e l a t i o n a n a l y s i s was a l s o conducted on a subset of data i n 1986. Adding s o l u b l e c a t i o n and SAR data to the a n a l y s i s r e s u l t e d i n a smaller sample s i z e (n=26) and produced a change i n the best p r e d i c t o r v a r i a b l e s , although these v a r i a b l e s are s t r o n g l y r e l a t e d to BD and exchangeable Na. Based on stepwise c o r r e l a t i o n a n a l y s i s the best combination c o n s i s t e d of -SAR, exchangeable Ca and h e i g h t -above-water (R 2 = 0.75) (Table 6.15). In the subsets i d e n t i f i e d by APC a n a l y s i s , -SAR and exchangeable Ca dominate. With the a d d i t i o n of p o r o s i t y data (n = 21), exchangeable Ca and -SAR became the subset best e x p l a i n i n g t o t a l f o l i a r cover. C o r r e l a t i o n a n a l y s i s of nestingboard cover w i t h environmental v a r i a b l e s revealed r e l a t i o n s h i p s s i m i l a r to those w i t h t o t a l f o l i a r cover. In 1985, the strongest c o r r e l a t i o n e x i s t e d between nestingboard cover and -BD, exchangeable -Na, and i n f i l t r a t i o n (median) (R 2 = 0.42, n = 78) . APC c o r r e l a t i o n was a l s o conducted on the 1985 data (Table 6 .15) . 66 In 1986, -height-above-water, EC, i n f i l t r a t i o n , -pH c and exchangeable -Na best e x p l a i n e d nestingboard cover (R^ = 0.50, n = 80). With the i n c l u s i o n of s o l u b l e cations, (n = 2 6), stepwise c o r r e l a t i o n i d e n t i f i e d -height-above-water, exchangeable Ca, SMg and -SK, and -SAR (R2=0.80) as the best subset. Table 6.15 M u l t i p l e c o r r e l a t i o n analyses of t o t a l f o l i a r and nestingboard cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05). Date Method n PV a V a r i a b l e s (R 2) T o t a l F o l i a r Cover 1985 APC 78 -pHw (.51), -BD (.47), N (0.34), & -Na (.32) SW 78 3 -BD and -Na (.59); -pH w & N; -BD & "PHW; -pH w & -Na; -pH w & C (0.56) -pHw, N & -Na; -BD, N & -Na (.61) -pHw, -Na & -BD (.64) 1986 APC 80 1 2 SW 80 26 21 4 3 2 -BD (.32), C (.29), & Ca 27) EC & -Na (.50), -BD & -Na (.44), -BD & Ca (.36) & -BD & - p H c & w (.31) H e i g h t b , EC & -Na (.52) EC, i n f i l & -Na (.52) EC, -BD & -Na (.51) -pH c, -BD & -Na (.48) -pH w, -BD & -Na (.44) EC, -BD, -Na & -pH c or -pH w (.56) EC, -BD, -Na & -pHc (0.56) -SAR, Ca & height (0.75) -SAR & Ca (0.68) 67 Table 6.15 continued. Date Method n PV a V a r i a b l e s (R 2) Nesting Board Cover 1985 APC 78 1 2 -Na (.28); ~pH w; -BD (.25) -BD & -Na (.39); i n f i l m e d b & -Na (.37); N & -Na; -pH w &. -Na (.35) 3 -BD, i n f i l m e d & -Na (.42); N, K & -Na; -height, -BD & -Na (.41) SW 78 3 -BD, -Na & i n f i l m e d (.42) 1986 SW 80 26 21 5 5 2 -height, EC, i n f i l , -pHc & -Na (.50) -height, Ca, SMg, -SK & -SAR -SAR & Ca (.72) (.80) PV: the number of p r e d i c t o r v a r i a b l e s . Height: height-above-water; I n f i l m e d : median i n f i l t r a t i o n . F. SEEDED AND NONSEEDED FOLIAR COVER Simple Linear Correlation In 1985, strong (P < 0.05) r e l a t i o n s h i p s were uncovered between seeded species cover and -slope, -pH, height-above-water, and exchangeable -Na. In 1986, seeded cover was not i n f l u e n c e d (P > 0.05) by any s o i l or s i t e c o n d i t i o n (Table 6.16) . Numerous environmental v a r i a b l e s a f f e c t e d (P < 0.05) nonseeded species cover i n 1985 and 1986 (Table 6.16). V a r i a b l e s c o r r e l a t e d w i t h nonseeded cover i n both years i n c l u d e d -pH w, -BD, Ca, EC, C, Mg, N, and i n f i l t r a t i o n . In a d d i t i o n , i n 1985 c l a y and P were p o s i t i v e l y c o r r e l a t e d , and 68 height-above-water was n e g a t i v e l y c o r r e l a t e d w i t h nonseeded cover. Exchangeable -Na, SCa, and a e r a t i o n and t o t a l p o r o s i t y a f f e c t e d nonseeded cover i n 1986 (Table 6.16) . Table 6.16 S o i l and s i t e v a r i a b l e s c o r r e l a t e d (P < 0.05) w i t h seeded and nonseeded species f o l i a r cover. Response V a r i a b l e Date P r e d i c t o r V a r i a b l e Seeded species f o l i a r cover 1985 -slope, - p H w & c , -Na, height 1986 Nothing s i g n i f i c a n t Nonseeded species 1985 & 1986 -BD, Ca, C, N, Mg, EC, f o l i a r cover i n f i l , & -pH w 1985 c l a y , P, i n f i l m e d , -pH c, & -height 198 6 t p o r , apor, -Na, SCa Multiple Linear Correlation Height-above-water, organic C and exchangeable -Na e x p l a i n e d seeded v e g e t a t i v e cover best i n 1985 (R 2 = 0.32, n=78) . This r e s u l t was achieved w i t h both stepwise and APC c o r r e l a t i o n a n a l y s i s (Table 6.17). In 1986, no s o i l or s i t e v a r i a b l e had a s i g n i f i c a n t e f f e c t on seeded cover, i n c l u d i n g analyses of data which i n c l u d e d s o l u b l e c a t i o n s , SAR and p o r o s i t y . Stepwise a n a l y s i s of nonseeded species cover w i t h s o i l data i n - 1985 generated the subset of -height-above-water, BD, i n f i l t r a t i o n and t o t a l N (R 2 = 0.63, n = 78) . In 1986, nonseeded cover was best e x p l a i n e d by C ( r 2 = 0.27, n = 8 0 ) . Table 6.17 presents the r e s u l t s of APC a n a l y s i s i n 1985 and 1986. 69 In 1986, w i t h the i n c l u s i o n of the s o l u b l e c a t i o n and SAR data (n = 26) , nonseeded cover and N were c o r r e l a t e d ( r 2 = 0.22). I n c l u s i o n . of the p o r o s i t y data (n = 21) produced a r e l a t i o n s h i p between nonseeded cover and exchangeable Ca and -SAR (R 2 = 0.49). Table 6.17 M u l t i p l e c o r r e l a t i o n analyses of seeded and nonseeded species f o l i a r cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05). Date Method n PV V a r i a b l e s (R 2) Seeded Species F o l i a r Cover 1985 APC 78 1 -Na (.23); height (.15) 2 Height & -Na (..29),- C & -Na (.28) 3 Height, C & -Na; height, i n f i l m e d & Na; height, N & -Na (.32) SW 78 3 Height, C & -Na (.32) 1986 SW 80 Nothing s i g n i f i c a n t 26 Nothing s i g n i f i c a n t Nonseeded Species Cover 1985 APC 78 1 N (.45); C (.44); & -BD (.39) 2 I n f i l & N (.54); -BD & N (.51) 3 -Height, I n f i l & N (.59); -BD, i n f i l & N; -height, -BD & i n f i l m e d (.56) 4 -Height, -BD, i n f i l & N (.63) SW 78 4 -Height, -BD, i n f i l & N (.63) 1986 SW 80 1 C (.27) 26 1 N (.22) 21 1 Ca & -SAR (.4 9) 70 6. GRAMINOID AND FORB FOLIAR COVER Simple Linear Correlation In 1985 and 1986, forb f o l i a r cover d e c l i n e d w i t h i n c r e a s i n g pH, BD, and exchangeable Na, and increa s e d as exchangeable Ca, C, N, and EC l e v e l s i n c r e a s e d (P < 0.05). Other s i g n i f i c a n t r e l a t i o n s h i p s i n 1985 i n c l u d e d -slope; i n 1986, i t i n c l u d e d i n f i l t r a t i o n , exchangeable Mg, a e r a t i o n and t o t a l p o r o s i t y , SMg and SCa, and -SAR (Table 6.18). Only -height-above-water was c o r r e l a t e d (P < 0.05) wit h graminoid f o l i a r cover i n both 1985 and 1986. In 1985, ne g a t i v e l y c o r r e l a t e d v a r i a b l e s i n c l u d e d pH, and BD; p o s i -t i v e l y c o r r e l a t e d v a r i a b l e s i n c l u d e d i n f i l t r a t i o n , C, and K (Table 6.18). Only height-above-water, i n f l u e n c e d graminoid cover i n 1986. Table 6.18 S o i l and s i t e v a r i a b l e s c o r r e l a t e d (P < 0.05) wit h forb and graminoid species f o l i a r cover. Response V a r i a b l e Date P r e d i c t o r V a r i a b l e Forb species f o l i a r cover 1985 & 1986 EC, N, Ca, C, pH w (-), BD (-) , & Na (-) 1985 slope (-) 1986 I n f i l , Mg, apor, t p o r , SMg, SAR (-), SCa Graminoid species 1985 & 1986 Height (-) f o l i a r cover 1985 In f i l m e d , i n f i l , C, K, PHw&c <->' & B D <-> 1986 Nothing s i g n i f i c a n t 71 M u l t i p l e Linear Correlation Bulk d e n s i t y (-), - p H c and exchangeable -Na best d e s c r i b e d forb f o l i a r cover i n 1985 (R 2 = 0.38, n = 78) . The best one-, two-, and t h r e e - v a r i a b l e subsets generated by APC are l i s t e d i n Table 6.19. In 1986, stepwise c o r r e l a t i o n a n a l y s i s i d e n t i f i e d -Na, EC, and -pH c as the best subset (R 2 = 0.48, . n = 80) . With s o l u b l e c a t i o n s i n c l u d e d i n the data set (n = 26) , Ca and SAR des c r i b e d f o r b f o l i a r cover p a t t e r n s best (R 2 = 0.58). The same subset was i d e n t i f i e d (R 2 = 0.69) w i t h p o r o s i t y data i n c l u d e d (n = 21) . Based on the 1985 stepwise a n a l y s i s , graminoid cover responded only to -pHc ( r 2 = 0.20, n = 78). A l l p o s s i b l e combinations a n a l y s i s confirms t h i s r e s u l t (Table 6.19). In 1986, graminoid cover was weakly c o r r e l a t e d w i t h -height ( r 2 = 0.05, n = 80). R e f l e c t i n g the low c o e f f i c i e n t of determination, no v a r i a b l e s were c o r r e l a t e d with graminoid cover when s o l u b l e c a t i o n and p o r o s i t y data were i n c l u d e d i n the a n a l y s i s (Table 6.19). 72 Table 6.19 M u l t i p l e c o r r e l a t i o n analyses of f o r b and graminoid species f o l i a r cover w i t h s o i l and s i t e v a r i a b l e s (P < 0.05). Date Method n PV V a r i a b l e s (R^) Forb Species F o l i a r Cover 1985 APC 78 1 -BD Ca ( (.28); -pH w (.21); N; & .19) 2 -BD & -Na (.34); -BD & -K; & - i n f i l m e d (.31) 3 - I n f i l m e d , EC & -Na (.39); -BD, -pH c & -Na (.38) SW 78 3 -BD, -pHc & -Na (.38) 1986 SW 80 26 21 3 2 2 -Na, Ca & Ca & EC & -pHc (.48) -SAR (.58) -SAR (.69) Graminoid Species F o l i a r Cover 1985 APC 78 1 - P H C (.20); -pH w (.10) 2 -Height & -pH c (.22); -pH c & Mg; -pH c & -Na (.21) 3 -Height, -pH c & Mg (.23) SW 7 8 1 -pHc (.20) 1986 SW 80 1 -Height (.05) 26 21 Nothing S i g n i f i c a n t Nothing S i g n i f i c a n t 73 H. INDIVIDUAL SPECIES FOLIAR COVER A l f a l f a No environmental v a r i a b l e s were s i g n i f i c a n t l y c o r r e -l a t e d w i t h a l f a l f a i n 1985 or 1986. Canada T h i s t l e Canada t h i s t l e responded (P < 0.05) t o f i v e e n v i r o n -mental v a r i a b l e s i n 1985 and 1986: -pH, -BD, exchangeable Ca, C, and N. Other v a r i a b l e s to which Canada t h i s t l e responded i n c l u d e c l a y and P i n 1985, and SCa, -SAR, exchangeable -Na, and t o t a l and a e r a t i o n p o r o s i t y i n 1986 (Table 6.20). The combination of i n f i l t r a t i o n (median) and C best d e s c r i b e d Canada t h i s t l e cover i n 1985 (R 2 = 0.36, n = 78). This subset was i d e n t i f i e d w i t h stepwise and APC analyses (Table 6.20). In 1986, the best subset of p r e d i c t o r v a r i a b l e s i n c l u d e d C again, but i n s t e a d of i n f i l t r a t i o n , exchangeable -Na was s e l e c t e d (R 2 = 0.18; n = 80). With the i n c l u s i o n of s o l u b l e c a t i o n s (n = 26) , Canada t h i s t l e f o l i a r cover responded most t o SCa ( r 2 = 0.17). A e r a t i o n p o r o s i t y and t o t a l p o r o s i t y were i d e n t i f i e d (R 2 = 0.57, n = 21) when c l a y and p o r o s i t y data were i n c l u d e d (Table 6.20) . 74 Table 6.20 Simple and m u l t i p l e c o r r e l a t i o n analyses of Canada t h i s t l e f o l i a r cover w i t h environmental v a r i a b l e s (P < 0.05) • A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 1985 & 1986 _ 1 -pH w; -BD; Ca; N; C L i n e a r 1985 - 1 c l a y ; P 1986 — 1 -SAR; SCa; t p o r ; apor; -Na Stepwise 1985 78 2 i n f i l m e d & C (0.36) 1986 80 2 C & -Na (0.18) 26 1 SCa (0.17) 21 2 apor & t p o r (.57) A l l P o s s i b l e Combinations 1985 78 1 i n f i l m e d (.34); C; & N (.17) 2 i n f i l m e d & C; i n f i l m e d & N (.36) 3 i n f i l m e d , C & K (.38) Crested Wheatgrass Crested wheatgrass cover decreased w i t h i n c r e a s i n g a l k a l i n i t y i n 1985 and 1986 (P < 0.05). This species responded n e g a t i v e l y to exchangeable Ca i n 1985 and p o s i t i v e l y t o SK i n 1986 (Table 6.2-1) . A strong negative r e l a t i o n s h i p e x i s t e d between c r e s t e d wheatgrass cover and BD and pH, as stepwise- c o r r e l a t i o n a n a l y s i s i d e n t i f i e d the subset of -BD and -pH c i n both 1985 and 1986 (R 2 = 0.33, n = 72, & R 2 = 0.21, n = 72, r e s p e c t -i v e l y ) . APC a n a l y s i s i n 1985 supports t h i s f i n d i n g (Table 6.21) . 75 Table 6.21 Simple and m u l t i p l e c o r r e l a t i o n analyses of c r e s t e d wheatgrass f o l i a r cover w i t h environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 19? 35 & 1986 — 1 ~PHw&c Lin e a r 1985 - 1 -Ca 1986 — 1 SK Stepwise 1985 72 2 -BD & -pH c (.33) 1986 72 2 -BD & -pH c (.21) A l l P o s s i b l e Combinations 1985 72 1 -pH c (.25) 2 -BD & -pH c (0.33); -pH c & -Ca (.31) 3 -BD, -pH c & N; -BD, -pH c & C (.34) F o x t a i l Barley F o x t a i l b a r l e y responded p o s i t i v e l y t o EC i n 1985 and 1986 (P < 0.05). In 1985, i t was a l s o c o r r e l a t e d w i t h -BD, c l a y , exchangeable K, Mg, and Na, and i n f i l t r a t i o n , whereas i n 198 6 height-above-water was the only other c o r r e l a t i v e v a r i a b l e (Table 6.22). Exchangeable Ca and Mg best d e s c r i b e d f o x t a i l f o l i a r cover i n 1985 (R 2 = 0.28, n = 78). This r e s u l t was achieved w i t h stepwise c o r r e l a t i o n a n a l y s i s and confirmed by . the r e s u l t s of APC a n a l y s i s (Table 6.22). In 1986, height-above-water was the best p r e d i c t o r v a r i a b l e ( r 2 = 0.04, n = 80). With the s o l u b l e c a t i o n s i n c l u d e d i n the data set (n = 26) , the v a r i a b l e s i d e n t i f i e d were exchangeable and s o l u b l e Mg (R 2 = 0.38) . An i d e n t i c a l 76 r e s u l t was obtained w i t h the i n c l u s i o n of c l a y and p o r o s i t y data (R 2 = 0.38, n = 21) . Table 6.22 Simple and m u l t i p l e c o r r e l a t i o n analyses of f o x t a i l b a r l e y f o l i a r cover and environmental v a r i a b l e s (P < 0.05) • A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 1985 & 1986 1 EC L i n e a r 1985 - 1 -BD; c l a y ; K; Na; Mg; & i n f i l (mean & median) 1986 — 1 -Height Stepwise 1985 78 2 Ca & Mg (0.28) 1986 80 1 -Height (.06) 26 2 Mg & SMg (.38) 21 2 Mg & SMg (.38) A l l P o s s i b l e Combinations 1985 78 1 Mg (.22); EC (. 11) 2 Ca & Mg (.28); Mg & Na; -pH w & Mg (.25) 3 -pH w, Ca & Mg ; Ca, Mg & -Na; i n f i l , . Ca & Mg (.29) Intermediate Wheatgrass Three s o i l f a c t o r s were c o r r e l a t e d (P < 0.05) wi t h intermediate wheatgrass i n 1985 and 1986: bulk d e n s i t y , exchangeable Na, and pH w. In c o n t r a s t to most other seeded and nonseeded species, intermediate wheatgrass responded p o s i t i v e l y t o these v a r i a b l e s . T a l l wheatgrass and s a l t meadow grass responded s i m i l a r l y . Other v a r i a b l e s w i t h s t r o n g r e l a t i o n s h i p s with t h i s species i n c l u d e -C, -Ca, and - c l a y i n 1985, and -SCa i n 1986. Table 6.23 l i s t s the simple l i n e a r c o r r e l a t i o n a n a l y s i s r e s u l t s . 77 Intermediate wheatgrass cover was best c o r r e l a t e d with pHw and -slope (R 2 = 0.48, n = 18) i n 1985. In 1986, pH w alone best e x p l a i n e d intermediate wheatgrass cover ( r 2 = 0.23, n = 24). A l l p o s s i b l e c o r r e l a t i o n a n a l y s i s a l s o i d e n t i f i e d pH w as the most important i n f l u e n c e on intermediate wheatgrass cover (Table 6.23). Table 6.23 Simple and m u l t i p l e c o r r e l a t i o n analyses of intermediate wheatgrass f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R^) Simple 1985 & 1986 1 pH w; BD; Na L i n e a r 1985 1 -Ca; -C; - c l a y 1986 — 1 pH c; -SCa Stepwise 1985 18 2 P Hw & -slope (0.48) 1986 . 24 1 PH W (0.23) A l l P o s s i b l e 1985 18 1 P Hw (.30); -Ca (.29); & Combinations Na ( .26) 2 PH W & -slope (. 48); & PH W & K (.38) 3 P Hw -slope, & K (.52); & PH W, -slope, & -Mg (.50) Creeping Red Fescue Creeping red fescue cover d e c l i n e d w i t h i n c r e a s i n g l e v e l s of exchangeable Na and p H ( w & c j i n 1985 and 1986. I t was p o s i t i v e l y c o r r e l a t e d with height-above-water i n 1985, arid w i t h C, and s o l u b l e Mg, K and Ca i n 198 6 (Table 6.24). In 1985, creeping red fescue cover's strongest r e l a t i o n s h i p w i t h environmental v a r i a b l e s e x i s t e d w i t h -pH w and - i n f i l t r a t i o n (R 2 = 0.17, n =.72). In 1986, -pH c e x p l a i n e d fescue cover best ( r 2 = 0.24, n = 72). The 78 stepwise and APC m u l t i p l e c o r r e l a t i o n r e s u l t s are provided i n Table 6.24. Table 6.24 Simple and m u l t i p l e c o r r e l a t i o n analyses of creeping red fescue f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R 2) Simple L i n e a r 1985 & 1986 1985 1986 - 1 1 1 -PHw&c' _ N a height C; SCa; SK; SMg Stepwise 1985 72 2 -pH w & - i n f i l (0.17) 1986 72 1 -pH c (0.24) A l l P o s s i b l e Combinations 1985 72 1 2 3 -pH w (.13); -Na (.12) -pH w & - i n f i l (. 17); -pH w & -Na; - i n f i l m e d & -pH w (.16) - i n f i l m e d , -pH w & -Na (.21) Salt Meadow Grass S a l t meadow grass d i d not respond t o any s o i l c o n d i t i o n i n both years (Table 6.25). In 1985, i t s cover dropped w i t h i n c r e a s i n g C (P < 0.05), and increased as the BD, pH, and exchangeable Na l e v e l s i ncreased — s i m i l a r t o the intermediate wheatgrass response. In 1986, only -SCa had a s i g n i f i c a n t e f f e c t on s a l t meadow grass f o l i a r cover (Table 6 .25) . In 1985, the strongest r e l a t i o n s h i p e x i s t e d between pH c and s a l t meadow grass f o l i a r cover ( r 2 = 0.09, n = 66) . An i d e n t i c a l r e s u l t was achieved w i t h APC a n a l y s i s , as pH c was the best s i n g l e v a r i a b l e subset ( r 2 = 0.09, n = 66). 79 S a l t meadow grass was not c o r r e l a t e d w i t h any v a r i a b l e i n 1986 (n = 64) (Table 6.25). Table 6.25 Simple and m u l t i p l e c o r r e l a t i o n analyses of s a l t meadow grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) • A n a l y s i s Date n PV V a r i a b l e (R 2) Simple L i n e a r 1985 1986 - 1 1 -C; Na; BD; p H w & c -SCa Stepwise 1985 66 1 pH c (0.09) 1986 64 Nothing s i g n i f i c a n t A l l P o s s i b l e Combinations 1985 66 1 2 3 pH c (.09); BD (.07) BD & Na; pH c & Ca (.10) slope, BD & Na (.10); s e v e r a l combinations (.09) Sedge species Sedge (Carex atherodes and C. rostrata) cover d e c l i n e d w i t h i n c r e a s i n g P H ( W & C ) i n 1985 and 1986, and with i n c r e a s i n g height-above-water i n 1985 (Table 6.26). pH c(-) was the v a r i a b l e best c o r r e l a t e d with sedge cover i n 1985 ( r 2 = 0.06, n = 78) and 1986 ( r 2 = 0.10, n = 80) . Sedge responded p r i m a r i l y to -pH c, even a f t e r the s o l u b l e c a t i o n s were i n c l u d e d i n the a n a l y s i s ( r 2 = 0.24, n = 26). pH c(-) was important i n the subsets s e l e c t e d w i t h APC a n a l y s i s i n 1985 (Table 6.26). 80 Table 6.26 Simple and m u l t i p l e c o r r e l a t i o n analyses of sedge f o l i a r cover and environmental v a r i a b l e s (P < 0.05) . A n a l y s i s Date n PV V a r i a b l e (R 2) Simple L i n e a r 1985 & 1986 1985 - 1 1 ~PHw&c -height Stepwise 1985 78 1 -pH c (0.06) 1986 80 26 21 1 1 -pH c (0.10) -pH c (0.24) Nothing s i g n i f i c a n t A l l P o s s i b l e . Combinations 1985 78 1 2 3 -pH c (.06) -pH c & -height (.0 9) -pH w, -height & -Ca (.10) Smooth Brome Grass Smooth brome grass was c o r r e l a t e d (P < 0.05) wi t h only one v a r i a b l e i n both 1985 and 1986: ~P H(c&w)- Other s i g n i f i c a n t , and negative, r e l a t i o n s h i p s e x i s t e d between t h i s species and EC and exchangeable Ca, Mg, and Na i n 1985. In 1986, brome cover decreased w i t h ' i n c r e a s i n g slope and inc r e a s e d w i t h an increase i n height-above-water (Table 6.27) . In 1985, smooth brome grass cover was s t r o n g l y t i e d to BD and -pHc (R 2 = 0.28, n = 78). This r e s u l t was achieved u s i n g stepwise and APC a n a l y s i s (Table 6.27). In 1986, the combination of -pH c, height-above-water, and exchangeable -Ca s i g n i f i c a n t l y i n f l u e n c e d smooth brome grass cover (R 2 = 0.29,' n = 80). Adding the s o l u b l e c a t i o n s 81 (n = 26) f o r stepwise a n a l y s i s r e s u l t e d i n the s e l e c t i o n of EC as the best subset ( r 2 = 0.22). Table 6.27 Simple and m u l t i p l e c o r r e l a t i o n analyses of smooth brome grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 1985 & 1986 - 1 ~PHw&c Lin e a r 1985 - 1 -Ca; -Mg; -EC; -Na 1986 — 1 -slope; height Stepwise 1985 78 2 BD & -pH c (0.28) 1986 80 3 -pH c, height & -Ca (0 26 2 -EC (0.22) 21 Nothing s i g n i f i c a n t A l l P o s s i b l e Combinations 1985 18 1 -pH c (.19); -Na (.06) 2 -pH c & BD (.28); & -pH c & -Mg (.27) 3 -pH c, BD, & -EC; -pH c, -Mg & K; & BD, -pH c & -Mg (.29) Sow T h i s t l e Sow t h i s t l e cover was n e g a t i v e l y a f f e c t e d (P < 0.05) by exchangeable Na i n both years. In 1985, i t responded to exchangeable -K, -pH w, -BD, C and N. EC was n e g a t i v e l y c o r r e l a t e d w i t h sow t h i s t l e i n 1986 (Table 6.28) . In 1985, sow t h i s t l e f o l i a r cover was best e x p l a i n e d by t o t a l N ( r 2 = 0.24, n = 78), whereas i n 1986 exchangeable -Na had the greatest i n f l u e n c e ( r 2 = 0.14, n = 80) (Table 6.28) . 82 No v a r i a b l e s were s i g n i f i c a n t when the s o l u b l e c a t i o n s , c l a y and p o r o s i t y v a r i a b l e s were i n c l u d e d i n . t h e a n a l y s i s . Table 6.28 Simple and m u l t i p l e c o r r e l a t i o n analyses of sow t h i s t l e f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R 2) Simple L i n e a r 1985 & 1986 1985 1986 - 1 1 1 -Na -pH w, -K, -BD; C; N -EC Stepwise 1985 . 78 1 N (.24) 1986 80 26 1 -Na (.14) Nothing s i g n i f i c a n t A l l P o s s i b l e Combinations 1985 78 1 2 3 N (.24); C (.22) C & N (.28); N & -K; N & -Mg (.26) C, N & -K (.32); C, N & -Mg (.31) T a l l Wheatgrass L i k e intermediate wheatgrass and s a l t meadow grass, t a l l wheatgrass responded p o s i t i v e l y to i n c r e a s i n g p H ( w & C ) and BD l e v e l s , and n e g a t i v e l y to exchangeable K. In 1986, exchangeable Ca, EC, and s o l u b l e K, Ca, and Mg were a l l n e g a t i v e l y c o r r e l a t e d with t a l l wheatgrass (Table 6.29). pH w was s e l e c t e d i n both years by stepwise c o r r e l a t i o n a n a l y s i s as the subset which best e x p l a i n e d t a l l wheatgrass f o l i a r cover (1985: r 2 = 0.10, n=60; 1986: r 2 = 0.26, n = 56). The APC r e s u l t s r e i n f o r c e the importance of a l k a l i n i t y to t h i s species (Table 6.29). 83 Table 6.29 Simple and m u l t i p l e c o r r e l a t i o n analyses of t a l l wheatgrass f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV Simple 1985 & 1986 _ 1 Lin e a r 1986 1 Stepwise 1985 . 60 1 1986 56 1 A l l P o s s i b l e 1985 60 1 Combinations 2 3 V a r i a b l e (R 2: PHw&c* B D ' " K -Ca; -EC; -satEC; -SK; -SCa & -SMg pH w (0.10) pH w (0.26) pH w (.10) pH w & Na (.13); four combinations (.10) pHw, -N, & -Na (.16); pH w, -C & -Na (.15) Whitetop Grass Whitetop grass cover responded n e g a t i v e l y (P < 0.05) t o BD and p o s i t i v e l y to EC and exchangeable Mg, K, and Ca i n both 1985 and 1986. In 1985, i t was a l s o c o r r e l a t e d with C, -height, -pH w, c l a y and N. T o t a l p o r o s i t y , exchangeable Na, satEC and i n f i l t r a t i o n had a p o s i t i v e e f f e c t on whitetop cover i n 1986 (Table 6.30). In 1985, stepwise a n a l y s i s ' i d e n t i f i e d exchangeable Ca and Mg and -height-above-water as the subset t h a t e x p l a i n e d whitetop f o l i a r cover best (R 2 = 0.39, n = 66). Table 6.30 presents the stepwise, and APC c o r r e l a t i o n a n a l y s i s r e s u l t s . In 1986, stepwise c o r r e l a t i o n i d e n t i f i e d EC and exchangeable K as the best p r e d i c t o r v a r i a b l e s f o r whitetop cover (R 2 = 0.58, n = 72). 84 Table 6.30 Simple and m u l t i p l e c o r r e l a t i o n analyses of whitetop grass f o l i a r cover and environmental v a r i a b l e s (P < 0.05) • A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 1985 & 1986 - 1 Ca; -BD; Mg; K; EC L i n e a r 1985 1 C; -height; -pH w; c l a y ; N 1986 1 t p o r ; satEC; Na; i n f i l Stepwise 1985 66 1 Ca, Mg, & -height (0.39) 1986 72 EC & K (.58) A l l P o s s i b l e 1985 66 1 Ca (.26); -BD (.22) Conditions 2 -Height & Ca (.35); -BD.& Ca (.29) 3 -Height, Ca & Mg (.39) Yellow Sweet Clover Exchangeable Ca was the only v a r i a b l e w i t h which y e l l o w sweet c l o v e r was c o r r e l a t e d (P < 0.05) i n 1985 and 1986. Yellow sweet c l o v e r responded to -slope, -BD, -pH w, -Na and height-above-water i n 1985, and t o exchangeable and SMg i n 1986 (Table 6.31). Yellow sweet c l o v e r f o l i a r cover was best d e s c r i b e d (R 2 = 0.19, n = 78) by height-above-water and exchangeable Ca i n 1985. Table 6.31 presents the stepwise and APC m u l t i p l e l i n e a r c o r r e l a t i o n r e s u l t s . In 1986, exchangeable Mg was i d e n t i f i e d by stepwise c o r r e l a t i o n a n a l y s i s as the best c o r r e l a t e ( r 2 = 0.09, n = 80). With the s o l u b l e c a t i o n s i n c l u d e d (n = 26), the combination of Ca, -N and SMg was the best subset (R 2 = 0.53) . 85 Table 6.31 Simple and m u l t i p l e c o r r e l a t i o n analyses of yellow sweet c l o v e r f o l i a r cover and environmental v a r i a b l e s (P < 0.05). A n a l y s i s Date n PV V a r i a b l e (R 2) Simple 1985 • & 1986 _ 1 Ca Li n e a r 1985 - • 1 -BD; -Na; -pH w; -slope & height 1986 — 1 SMg; & Mg Stepwise 1985 7 8 2 Height & Ca (0.19) 1986 80 1 Mg (.09) 26 3 Ca, -N & SMg (.53) 21 Nothing s i g n i f i c a n t A l l P o s s i b l e 1985 78 1 Height (..11) ; Ca (. 10) Combinations 2 Height & Ca; EC & -Na (.19) 3 EC, C & -Na (.26); Height, EC & -Na (.23) 86 7. DISCUSSION A. ISLAND FLORA Although species r i c h n e s s ( i . e . , number of species) dropped 32% from 1985 (59) t o 1986 (40), sampling i n t e n s i t y dropped a corresponding amount, as fewer t o t a l quadrats were sampled on fewer i s l a n d s (Table 5.1). A l l the dominant seeded and nonseeded species, f o r example t a l l wheatgrass and yellow sweet c l o v e r , and Canada t h i s t l e and sow t h i s t l e , were recorded both years (Table 6.1). Rare and i n f r e q u e n t l y recorded species account f o r most of the d i f f e r e n c e between years. A l s o , because the i s l a n d s h o r e l i n e was more c o n s i s t e n t l y d e f i n e d i n 1986, some emergent species were excluded i n tha t year. Most of these s p e c i e s , f o r example B a l t i c rush and silverweed, are i n s i g n i f i c a n t i n terms of f o l i a r cover. Reports of species r i c h n e s s from other reclamation s t u d i e s i n d i c a t e that i s l a n d species r i c h n e s s i s moderate. For example, 245 species were recorded on abandoned c o a l -mined land i n the A l b e r t a f o o t h i l l s ( R u s s e l l 1985) , and 141 species were found on l a n d s l i d e s i n the Cascade Mountains (Miles and Swanson 1986). The A l b e r t a study i n c l u d e d s i t e s g r e a t e r than 30 years o l d occupying areas encompassing 12-170 ha, and the l a n d s l i d e study i n c l u d e d s i t e s 6 to 28 years o l d . In c o n t r a s t , the study i s l a n d s were l e s s than s i x years o l d and l e s s than 500 m2 i n area. I s l a n d species r i c h n e s s compares favourably to some North Dakota coal-mined lands, where only 30 species invaded during the f i r s t four 87 years f o l l o w i n g abandonment (Iverson and Wall 1982) . S u r p r i s i n g l y , these mined lands were recovered w i t h p r a i r i e t o p s o i l , which not only provides a s u i t a b l e seedbed, but a l s o a seedbank of n a t i v e s p e c i e s . Gramineae, Compositae and Cyperaceae were the three l a r g e s t f a m i l i e s . Numerous mined-land s t u d i e s have noted the predominance of Gramineae and Compositae ( R u s s e l l 1985). The three predominant nonseeded species, sow t h i s t l e , Canada t h i s t l e and f o x t a i l b a r l e y , belong to these F a m i l i e s . These p i o n e e r i n g species are noted f o r t h e i r a b i l i t y t o c o l o n i z e d i s t u r b e d areas q u i c k l y and t o l e r a t e adverse c o n d i t i o n s . The seeds of these species are capable of widespread and r a p i d d i s p e r s a l . Compositae species are noted f o r t h e i r d i s p e r s a l c a p a b i l i t i e s (Morris et a l . 1986). Iverson and Wali (1982) recorded f o x t a i l b a r l e y i n the second year f o l l o w i n g abandonment of a coal-mine. These three species, along w i t h n a t i v e species, formed an important p a r t of the i s l a n d v e g e t a t i o n . F i v e seeded species, t a l l wheatgrass, intermediate wheatgrass, smooth brome grass, creeping red fescue and yellow sweet c l o v e r , had r e l a t i v e l y high frequency and coverage. Intermediate and t a l l wheatgrass are t a l l , rank and coarse-leaved grasses. The former species i s considered the l e a s t s a l t t o l e r a n t of the two and i t i s rhizomatous; however, i t tended to form l a r g e bunches on i s l a n d s , s i m i l a r to t a l l wheatgrass. T a l l wheatgrass i s a bunchgrass noted f o r i t s t o l e r a n c e of s a l i n e and a l k a l i n e c o n d i t i o n s . Yellow 88 sweet c l o v e r , a b i e n n i a l , provides low, dense growth i n the f i r s t year, and t a l l , dense growth i n the second, or f l o w e r i n g year. The importance of these three species to i s l a n d cover l i e s i n t h e i r coarse and dense growth form, which provides good n e s t i n g cover. The two t u r f grasses, smooth brome grass and creeping red fescue were f r e q u e n t l y recorded (40 --50%-- of the quadrats), but c o n t r i b u t e d l i t t l e t o the f o l i a r cover. Both these species are rhizomatous. Creeping red fescue tended to be short, narrow-leaved and formed a sparse t u r f , o f t e n beneath the canopy of the t a l l e r forbs and grasses; consequently, i t i s termed a bottom grass (Walton 1983). Smooth brome grass, although l a r g e r than creeping red fescue, o f t e n produced a r e l a t i v e l y open sward. Crested wheatgrass and a l f a l f a were unimportant i n both respects — cover and frequency. Crested wheatgrass was expected t o perform w e l l because of i t s t o l e r a n c e to adverse c o n d i t i o n s ; however, the i s l a n d s may have been too a l k a l i n e . A l f a l f a does not compete w e l l w i t h aggressive weeds and grasses, and i s s e n s i t i v e t o sodic and a l k a l i n e c o n d i t i o n s . A l s i k e c l o v e r was the only seeded species not recorded; however, i t was only seeded, i n 1979, at Kingston Slough. This c l o v e r i s a s h o r t - l i v e d p e r e n n i a l so i t i s u n l i k e l y to p e r s i s t longer than a year, i f i t e s t a b l i s h e s at a l l , under the h i g h l y a l k a l i n e and sodic c o n d i t i o n s of t h i s i s l a n d . 89 In general, both nonseeded and seeded species played important r o l e s i n ve g e t a t i n g i s l a n d s . The importance of some of the seeded species i s r e f l e c t e d by the high frequency and coverage values recorded. On the s o l e b a s i s of t h e i r high frequency and cover, nonseeded species are important c o n s t i t u e n t s of the i s l a n d v e g e t a t i o n . The f a c t t h a t > 40 species were recorded on the i s l a n d s , i s f u r t h e r i n d i c a t i o n t h a t n a t u r a l succession i s an important process on i s l a n d s . The response and r o l e of the va r i o u s species are d i s c u s s e d l a t e r i n t h i s chapter. B. ISLAND SOIL AND SITE CONDITIONS The i s l a n d s o i l s f i t a continuum ranging from h i g h l y sodic and a l k a l i n e , f o r example Kingston Slough and Ro l l y v i e w Marsh, t o r e l a t i v e l y n e u t r a l l e v e l s of a l k a l i n i t y and s o d i c i t y , f o r example Louis Lake, Waskwei Creek, and Z i l k e Marsh. T y p i c a l of p r a i r i e s o i l s , most of the i s l a n d s are moderately s a l i n e . S a l i n i t y l e v e l s of the i s l a n d s o i l s were r e l a t i v e l y low, based on standards set f o r s o i l s u t i l i z e d i n p l a i n s r eclamation i n A l b e r t a ( S o i l Q u a l i t y C r i t e r i a Working Group 1987). S a l i n i t y l e v e l s between 4 and 8 dS/m impose severe s o i l l i m i t a t i o n s on p l a n t growth, and thus have a s u i t a b i l i t y r a t i n g f o r t o p s o i l as poor. Only Houcher F l a t and Lake, Kingston Slough and R o l l y v i e w Marsh had mean e l e c t r i c a l c o n d u c t i v i t y (EC) l e v e l s between 4 and 8 dS/m (Table 6.7) . In 1985, Ro l l y v i e w Marsh I s l a n d No. 2 had a 90 mean EC of 5.4 dS/m — the maximum recorded i n e i t h e r year. Hebert Lake and Reta P r o j e c t w i t h s a l i n i t y l e v e l s below 2 dS/m have no or only s l i g h t l i m i t a t i o n s f o r growth. By comparison, EC values > 8 dS/m were recorded during a study of subsurface drainage of s a l i n e s o i l s i n southern A l b e r t a (Sommerfeldt and Chang 1987). On bent o n i t e mine s p o i l s i n Montana, aged 5 t o 28 years, EC v a r i e d from 5.5 to 9.3 dS/m (Sieg et a l . 1983). These values are co n s i d e r a b l y higher than the i s l a n d values. S o i l s w i t h sodium adsorption r a t i o (SAR) values greater than 12 are considered u n s u i t a b l e f o r p l a n t growth because chemical or p h y s i c a l p r o p e r t i e s are so severe t h a t reclamation would not be economically f e a s i b l e ( S o i l Q u a l i t y C r i t e r i a Working Group 1987). These s o i l s are considered u n s u i t a b l e f o r use as both t o p s o i l , or s u b s o i l . Kingston Slough (42.4), Paulgaard Marsh (28.8) and R o l l y v i e w Marsh (32.0) f i t t h i s category (Table 6.9). Hebert Lake and Houcher Lake s o i l s r a t e d poor, t h a t i s , they possessed c o n d i t i o n s t h a t pose severe l i m i t a t i o n s t o growth. Houcher F l a t probably f i t s t h i s category a l s o as i t s s o i l i s s i m i l a r t o Houcher Lake s o i l ; however, Houcher F l a t was not analysed f o r s o l u b l e c a t i o n s (because of f i n a n c i a l c o n s t r a i n t s ) . I s l a n d s o i l s r a t e d good, w i t h no l i m i t a t i o n s t o p l a n t growth, i n c l u d e B u t t e r Lake.. Louis Lake, Waskwei Creek and Z i l k e Marsh. These i s l a n d s tended t o have the best f o l i a r cover (Table 6.2). Marstrand P r o j e c t was the only p r o j e c t r a t e d f a i r , having moderate l i m i t a t i o n s . 91 Exchangeable sodium percentage (ESP) values r e v e a l almost i d e n t i c a l trends to the SAR values (Table 6.9). The p r o j e c t s w i t h the highest SAR a l s o had the highest ESP, and the p r o j e c t s w i t h low SAR had a low ESP. Hebert Lake ESP ranked 4th as d i d i t s SAR l e v e l ; however, u n l i k e the SAR, i t s ESP was c l o s e t o the l e v e l s of the h i g h l y sodic wetlands. Absolute values of exchangeable Na show pat t e r n s s i m i l a r t o ESP and SAR (Table 6.8), but they are not as w e l l - d e f i n e d and can be mislea d i n g because of the d i f f e r e n c e s i n s o i l c a t i o n exchange c a p a c i t y (CEC). Knowing the CEC of the s o i l allows the e f f e c t of exchangeable Na on the s o i l and p l a n t to be estimated. Base s a t u r a t i o n (BS) values could not be c a l c u l a t e d because of the presence of calcium carbonate (CaCC^) i n the s o i l . Calcium carbonate causes an over e s t i m a t i o n of exchangeable Ca thus b i a s i n g the BS upwards, oft e n over 100%. In general s o i l effervescence, an estimate of CaCC>3 i n the s o i l , was weak, although the study i n c l u d e d i s l a n d s w i t h strong to no effervescence. The degree of effervescence does not appear r e l a t e d to v e g e t a t i v e cover. A p o s i t i v e response to CaCC>3 would be expected i f some of the i s l a n d s o i l s were a c i d i c or low i n Ca. Potassium i s a n u t r i e n t seldom d e f i c i e n t i n A l b e r t a s o i l s and the i s l a n d s o i l s r e f l e c t t h i s (Table 6.8). Mean exchangeable K was 1.2 cmol/kg (907 kg/ha), comparable to l e v e l s found i n bentonite mine s p o i l s (Sieg et a l . 1983). A l b e r t a A g r i c u l t u r e (1985) considers K l e v e l s g r e a t e r than 92 335 kg/ha to be adequate f o r crop use. Only Louis Lake i s l a n d i n 1985 was considered to be moderately d e f i c i e n t i n exchangeable K; i n 198 6 exchangeable K was adequate. Louis Lake s o i l i s r e l a t i v e l y sandy, and sandy s o i l s tend t o be d e f i c i e n t i n K. Hebert Lake i s l a n d s are a l s o q u i t e sandy; consequently the K l e v e l s were r e l a t i v e l y low there too, though s t i l l adequate f o r crop use. Magnesium concentrations were a l l high and s u f f i c i e n t f o r crop use (Table 6.8) . Houcher Lake and F l a t had the highest exchangeable Mg l e v e l s . Islands of both these p r o j e c t s are extremely clayey, r e f l e c t i n g the importance of t h i s n u t r i e n t i n secondary c l a y minerals, such as i l l i t e and m o n t m o r i l l o n i t e (Tisdale et a l . 1985). S o i l pH w averaged 7.4 i n 1985 and 8.1 i n 198 6 (Table 6.10). The former l e v e l i s considered good (6.5 - 7.5) with no l i m i t a t i o n s f o r p l a n t growth, whereas the 1986 l e v e l i s r a t e d f a i r (7.6 - 8.5) w i t h s l i g h t l i m i t a t i o n s ( S o i l Q u a l i t y C r i t e r i a Working Group 1987). The 1985 r e s u l t i s higher than the pH values a t t a i n e d on the bentonite mine s p o i l s i n Montana (5.6 - 6.9) and the adjacent n a t i v e grasslands (7.1). In 1985 the f o l l o w i n g p r o j e c t s were r a t e d good: B u t t e r Lake, Houcher F l a t and Lake, Louis Lake, Marstrand P r o j e c t , Reta P r o j e c t , Waskwei Creek, and Z i l k e Marsh. In 1986, only Houcher F l a t and Lake and Waskwei Creek r a t e d good (Table 6.10). In 1985, Hebert Lake and R o l l y v i e w Marsh i s l a n d s had a pH w > 8.5, p l a c i n g these s o i l s i n the poor (8.6 - 9.0) 93 category, w i t h moderate l i m i t a t i o n s f o r p l a n t growth. In 1986, the former two p r o j e c t s as w e l l as Kingston Slough and Paulgaard Marsh had an u n s u i t a b l e (> 9.0) r a t i n g , i n d i c a t i n g severe l i m i t a t i o n s to p l a n t growth. No p r o j e c t s r a t e d poor i n 1986 or u n s u i t a b l e i n 1985. D i f f e r e n c e s between years may be a t t r i b u t a b l e to y e a r l y v a r i a t i o n i n temperature and p r e c i p i t a t i o n , which a f f e c t s o i l moisture and s a l t l e v e l s , sampling v a r i a t i o n , and l a b o r a t o r y instrument and a n a l y s i s v a r i a t i o n . C ation exchange c a p a c i t y (CEC) was r e l a t i v e l y uniform and high, w i t h most s o i l s ranging from 20 t o 40 cmol/kg. DU tends to s e l e c t areas f o r i s l a n d c o n s t r u c t i o n t h a t have good f i n e - p a r t i c l e d b u i l d i n g m a t e r i a l , such as s i l t and c l a y , and c l a y , i n p a r t i c u l a r , c o n t r i b u t e s a l o t t o s o i l CEC. Houcher Lake CEC was p a r t i c u l a r l y high (62.2 cmol/kg), r e f l e c t i n g the extremely high c l a y l e v e l i n the i s l a n d s o i l (Table 6.12). The i s l a n d s o i l s w i t h low CEC - Hebert Lake, Paulgaard and R o l l y v i e w Marsh - tended to have low (< 1 1/2%) organic carbon l e v e l s (Table 6.9). Organic C provides an index to the organic matter l e v e l s i n the s o i l . . In 1985 and 1986, three p r o j e c t s had C l e v e l s < 1%: Hebert Lake, Kingston Slough and R o l l y v i e w Marsh.- Carbon l e v e l s < 1% are considered poor to u n s u i t a b l e and impose severe l i m i t a t i o n s to p l a n t growth because of the p h y s i c a l e f f e c t on the s o i l . B u t t e r Lake and Paulgaard Marsh l e v e l s were f a i r i n 1985 and 1986, between 1 and 2%. The remaining i s l a n d s had l e v e l s > 2%. Louis Lake s o i l had 94 extremely high C l e v e l s (> 12.5%). Waskwei Creek s o i l s were > 5% C i n both years (Table 6.10). By cpmparison, Black Chernozems i n the study area ( E l l e r s l i e , A l b e r t a ) averaged 6.5% t o t a l C (Dinwoodie and Juma 1988). T o t a l n i t r o g e n was d i r e c t l y c o r r e l a t e d w i t h C ( r 2 = 0.99, P < 0.001, n = 78 and 26 i n 1985 & 1986); consequently e v a l u a t i o n of N y i e l d s the same r e s u l t s as f o r C. Mean t o t a l N was 0.24% (Table 6.10), whereas the average value on Black Chernozems near the study s i t e s was near 0.53% (Dinwoodie and Juma 1988). Phosphorus l e v e l s were r e l a t i v e l y low at a l l p r o j e c t s but Houcher Lake, which had good P l e v e l s (-87.5 ppm) . Most of the i s l a n d s o i l s had P l e v e l s between 5 and 15 ppm. Bulk d e n s i t y (BD) i n n a t u r a l s o i l s i s commonly around 1500 kg/m3 (Sims et a l . 1984), while optimum BD i n c u l t i v a t e d s o i l s i s about 1200 kg/m3. Bulk d e n s i t y a f t e r c u l t i v a t i o n may be only 1000 kg/m3. I s l a n d BD averaged between 1050 and 1150 kg/m3 i n 1985 and 1986 (Table 6.11). Three i s l a n d s , Hebert Lake, Kingston Slough and R o l l y v i e w Marsh, which had r e l a t i v e l y high BD (> 1400 kg/m 3), a l s o had very low C l e v e l s . In c o n t r a s t , Louis Lake w i t h very high C l e v e l s had a BD of < 500 kg/m3. The l a t t e r s o i l i s almost an organic s o i l , w ith 22% organic matter. The i s l a n d BD values are s i m i l a r t o those measured elsewhere. Bulk d e n s i t y averaged 1300 kg/m3 on Brown Chernozems i n southern A l b e r t a (Dormaar and Smoliak 1985) 95 and averaged 850 kg/mJ on a Black Chernozem near the study s i t e s (Dinwoodie and Juma 1988). Clay l e v e l s were not excessive, ranging from 10-35% (Table 6.12), and comparable to those i n I l l i n o i s c o a l mine s p o i l s (Indorante et a l . 1981). Houcher F l a t and Lake i s l a n d s were exceptions, as c l a y comprised approximately 75% of the t o t a l mass. S o i l p o r o s i t y r e f e r s t o the volume percentage of bulk s o i l not occupied by the s o l i d s . P o r o s i t y i s comprised of two components: a e r a t i o n (or macropore) and w a t e r - r e t e n t i o n (or micropore) p o r o s i t y , both of which p l a y important r o l e s i n determining s o i l s t r u c t u r e and hydrology. I d e a l l y , t o t a l s o i l p o r o s i t y should be > 50%. Mean i s l a n d p o r o s i t y was near optimum, at 59.2%, and ranged from 47.3% at Kingston Slough t o 77.3% at Louis Lake (Table 6.12), an i s l a n d high i n organic matter. Although i s l a n d t o t a l p o r o s i t y l e v e l s were c l o s e to optimum, a e r a t i o n p o r o s i t y was f a r below optimum. Gener a l l y , a e r a t i o n and w a t e r - r e t e n t i o n p o r o s i t y are equal; t h e r e f o r e both should be about 25% of the t o t a l volume. A e r a t i o n p o r o s i t y of the i s l a n d s , however, averaged only 11.0%, wi t h the greatest value being 18.9% at Louis Lake. Louis Lake s o i l had good t i l t h and n u t r i e n t s t a t u s , and the low a e r a t i o n p o r o s i t y i s compensated f o r by the high o v e r a l l p o r o s i t y . On other i s l a n d s , low a e r a t i o n p o r o s i t y i s compounded by low t o t a l p o r o s i t y , which reduces water 96 i n f i l t r a t i o n and drainage, and i n h i b i t s s e e d l i n g establishment and root p e n e t r a t i o n . Mean steady-state i n f i l t r a t i o n r a t e s v a r i e d c o n s i d e r a b l y between 1985 and 1986: 64.8 cm/h i n 1985 and 13.0 cm/h i n 1986 (Table 6.13). The lower r a t e i n 1986 i s a t t r i b u t a b l e to more c o n s i s t e n t placement of the s i n g l e - r i n g i n f i l t r o m e t e r s used to measure i n f i l t r a t i o n . In 1986, the s o i l was always moistened p r i o r to i n s e r t i n g the cans, and muskrat burrows or hollows were avoided. In a d d i t i o n , high r a i n f a l l r a t e s i n 198 6 meant th a t c o n s i s t e n t l y a c h i e v i n g steady-state i n f i l t r a t i o n was more l i k e l y . I n f i l t r a t i o n was high on Louis Lake s o i l s , which were c h a r a c t e r i z e d by low BD and SAR, and high C. I n f i l t r a t i o n was a l s o high on Houcher F l a t and Lake, the former i n p a r t i c u l a r ; however, t h i s i s probably a t t r i b u t a b l e to the l a r g e number of muskrat runs l o c a t e d i n the i s l a n d s , not j u s t to the s o i l s t r u c t u r e . Muskrat runs create l a r g e cracks and holes t h a t increase i n f i l t r a t i o n r a tes tremendously. I n f i l t r a t i o n on Hebert Lake, Kingston Slough and R o l l y v i e w Marsh i s l a n d s was n e g l i g i b l e (< 0.1 cm/h). These i s l a n d s , i n c o n t r a s t to Louis Lake, were low i n organic carbon, with high BD and SAR. S o d i c i t y i s a prime cause of low i n f i l t r a t i o n r a t e s i n A l b e r t a (Sims e t ' a l . 1984) because i t destroys the s o i l s ' p h y s i c a l s t r u c t u r e ; s o d i c i t y appears to a f f e c t i n f i l t r a t i o n on i s l a n d s a l s o . The 1986 i n f i l t r a t i o n r a t e compares favourably to r a t e s recorded on rangelands i n Texas. On 97 deep (> 30 cm) stoney and s i l t y c l a y s o i l s i n exclosures and r o t a t i o n a l g r a z i n g pastures, i n f i l t r a t i o n v a r i e d from 10 to 14 cm/h (McGinty et a l . 1979). Under heavy continuous g r a z i n g , which compacts s o i l , the i n f i l t r a t i o n r a t e dropped to between 3 and 6 cm/h, reg a r d l e s s of s o i l depth. S i t e c h a r a c t e r i s t i c s tend to be uniform between i s l a n d s . Average slope of quadrats i s seldom over 10^ and most quadrats faced NW or E, l i k e l y a consequence of i s l a n d s being c o n s t r u c t e d p a r a l l e l t o p r e v a i l i n g n orth winds. Most quadrats were i n the middle or upper slope p o s i t i o n s , and the microtopography was seldom rougher than s l i g h t l y mounded. Mean quadrat height-above-water v a r i e d between i s l a n d s , but was always < 1 m. Compared to other s i t e v a r i a b l e s , t h i s v a r i a b l e probably had the gr e a t e s t e f f e c t on p l a n t cover, because of i t s e f f e c t on water a v a i l a b i l i t y . C. TOTAL FOLIAR COVER I s l a n d v e g e t a t i o n i s c l o s e l y a s s o c i a t e d w i t h the chemical and p h y s i c a l c o n d i t i o n s of the s o i l . F o l i a r cover, and t h e r e f o r e , v e g e t a t i o n establishment, appears to be a f f e c t e d by three primary f a c t o r s : . s a l t c o n c e n t r a t i o n s , a l k a l i n i t y and bulk d e n s i t y . These f a c t o r s i n f l u e n c e f o l i a r cover d i r e c t l y through t h e i r e f f e c t on p l a n t growth, and i n d i r e c t l y by t h e i r combined e f f e c t on s o i l c o n d i t i o n s . The ma j o r i t y (> 95%) of p r e d i c t o r v a r i a b l e s i d e n t i f i e d by simple c o r r e l a t i o n are d i r e c t or i n d i r e c t measures of these f a c t o r s (Table 6.14). In both 1985 and 1986 f o l i a r cover was 98 n e g a t i v e l y c o r r e l a t e d with a combination of exchangeable Na, BD and pH (Table 6.15). Although constructed at d i f f e r e n t times, i s l a n d age was not c o r r e l a t e d (P > 0.05) w i t h f o l i a r cover. S o i l moisture, too, was not an important v a r i a b l e . Some of the i s l a n d s w i t h the poorest cover were o f t e n water-logged on the surfac e , w i t h pools of water p e r s i s t i n g on the i s l a n d top. Both i s l a n d age and s o i l moisture were of secondary importance compared to the three s o i l f a c t o r s given above. The environment-vegetation r e l a t i o n s h i p s , i d e n t i f i e d by stepwise c o r r e l a t i o n a n a l y s i s , d i f f e r e d between years only because the 1986 equation i n c l u d e d the v a r i a b l e EC, as w e l l as BD, exchangeable Na and pH. In both years, stepwise and APC m u l t i p l e c o r r e l a t i o n accounted f o r about 60% of the v a r i a t i o n found i n f o l i a r cover. In 1986, even without EC, the combination of BD, exchangeable Na, and pH was s i g n i f i c a n t (R 2 = 0.44). Table 6.15 i n c l u d e s a l i s t of s e v e r a l other s i g n i f i c a n t r e l a t i o n s h i p s ; however, most of these are rearrangements of pH, exchangeable Na, t o t a l N, and BD i n 1985, and BD, exchangeable Na and Ca, EC, and pH i n 1986. The e f f e c t s a l t s have on v e g e t a t i v e growth on i s l a n d s i s r e f l e c t e d i n the number of s i g n i f i c a n t v a r i a b l e s t h a t a f f e c t i s l a n d s o d i c i t y and s a l i n i t y . In 1985, 3 out of 8 v a r i a b l e s c o r r e l a t e d with f o l i a r cover were c a t i o n s (exchangeable Ca, Mg and -Na) ;. i n 1986, 7 out of 14 were measures of s a l t c o n c e n t r a t i o n s . The f o l l o w i n g v a r i a b l e s 99 were s i g n i f i c a n t during one year at l e a s t : EC, SAR, exchangeable Na, and so l u b l e and exchangeable Ca and Mg (Table 6.14) . Res u l t s of the m u l t i p l e c o r r e l a t i o n analyses a l s o suggest th a t excess s a l t s are an important f a c t o r (Table 6.15). Exchangeable Na was a s i g n i f i c a n t p r e d i c t o r v a r i a b l e i n one-, two- and t h r e e - v a r i a b l e equations i n 1985 and 1986. EC was important i n 1986 a l s o . With s o l u b l e c a t i o n and SAR data i n c l u d e d i n the a n a l y s i s , SAR and exchangeable Ca were the most important determinants of ve g e t a t i v e cover. In a l l cases, exchangeable Na n e g a t i v e l y i n f l u e n c e s p l a n t growth, whereas exchangeable Ca and Mg both have a p o s i t i v e i n f l u e n c e . The presence of la r g e amounts of s o l u b l e Ca and Mg, r e l a t i v e t o s o l u b l e Na, always had a p o s i t i v e e f f e c t . The SAR values i n Table 6.9 i s a measure of t h i s r e l a t i o n s h i p . Hamm (1982) s t u d i e d man-made and n a t u r a l i s l a n d s i n DU p r o j e c t s i n c e n t r a l and southern Saskatchewan. S a l i n i t y was i d e n t i f i e d as the major o b s t a c l e t o good v e g e t a t i o n establishment i n 54% of the wetlands. Lack of organic matter and s o i l f e r t i l i t y were i d e n t i f i e d as l e s s important problems (20% of wetlands) . Hamm (1982) considered v e g e t a t i o n establishment on i s l a n d s as f e a s i b l e because n a t u r a l i s l a n d s i n more s a l i n e wetlands and w i t h very s a l i n e s o i l s were w e l l vegetated. Man-made i s l a n d s may g r a d u a l l y be d e s a l i n i z i n g because the surface (0 - 15 cm) s a l i n i t y was 100 o f t e n 50 - 75% lower than the 15 - 30 cm and 30 - 60 cm depths. Thus f a r , a d i s t i n c t i o n has not been made between the d i f f e r e n t types of s a l t - a f f e c t e d s o i l s . S a l i n e s o i l s are those having a high s a l t content, whereas sod i c s o i l s have a high Na content. Under s a l i n e c o n d i t i o n s Ca and Mg are the dominant c a t i o n s i n s o l u t i o n and on the exchange complex. Sulphate (SO4-) and c h l o r i d e ( C l - ) are the major anions. As s a l t s accumulate i n the s o i l , Ca and Mg s a l t s p r e c i p i t a t e and Na becomes dominant. When Na comprises 50% of the s a l t s i n s o l u t i o n , i t begins to replace d i v a l e n t c a t i o n s on the exchange complex, and the s o i l s become s o d i c . In sodic s o i l s , Na i s the dominant c a t i o n and sulphate, bicarbonate (HCO3-), and c h l o r i d e are the major anions. I f carbonate (CO3-) i s abundant the pH u s u a l l y r i s e s above 8.5 (Sims et a l . 1984). Although s a l i n i t y i s an important f a c t o r i n the i s l a n d environment, the c o n s i s t e n t i d e n t i f i c a t i o n of exchangeable Na and SAR as important v a r i a b l e s i n c o r r e l a t i o n s , suggests s o d i c i t y i s the main concern (e.g. Table 6.15). S o d i c i t y i s a major concern because of i t s c a u s t i c e f f e c t on p l a n t growth, the negative e f f e c t i t has on s o i l s t r u c t u r e , and the s p e c i a l management r e q u i r e d . . S o i l s high i n s o l u b l e s a l t s reduce the a v a i l a b i l i t y of water t o p l a n t s by i n c r e a s i n g the osmotic c o n c e n t r a t i o n of the s o i l s o l u t i o n (Ray 1972) . S o i l s a l i n i t y has v a r y i n g 101 e f f e c t s on p l a n t s , depending on the type of s a l t and p l a n t s p e c i e s . Sodic s o i l s , those high i n Na, have a s i m i l a r osmotic e f f e c t on p l a n t s ; however, sodic s o i l s a l s o destroy s o i l s t r u c t u r e and are h i g h l y a l k a l i n e . A l k a l i n i t y i s d i s -cussed l a t e r i n t h i s chapter. S o i l s are c l a s s i f i e d as non-saline, s a l i n e , s o d i c -s a l i n e or s o d i c . Non-saline s o i l s have an EC < 4 dS/m and an ESP < 15%. Islands i n B u t t e r Lake, Louis Lake, Marstrand P r o j e c t , Waskwei Creek, and Z i l k e Marsh can be c a t e g o r i z e d as n o n - s a l i n e . S a l i n e s o i l s have an EC > 4 dS/m, but an ESP < 15%. No i s l a n d s f i t t h i s d e s c r i p t i o n . S a l i n e - s o d i c s o i l s have an EC > 4 dS/m and an ESP > 15%, whereas sodic s o i l s have an EC < 4 dS/m and an ESP > 15%. F i v e i s l a n d s o i l s f i t the sodic category: Hebert Lake, Houcher F l a t , Kingston Slough (Figure 4) and Paulgaard and R o l l y v i e w Marshes (Figure 5). Based on the 1986 satEC values, Kingston Slough (4.6 dS/m) and Houcher Lake (5.0 dS/m) could f i t the s a l i n e - s o d i c category. Kingston Slough (pH w = 9.2), however, along w i t h Hebert Lake (9.4), Paulgaard Marsh (9.5), and R o l l y v i e w Marsh (9.4) had pH w values greater than 8.5 - the t h e o r e t i c a l maximum f o r s a l i n e - s o d i c s o i l s . This suggests t h a t Kingston Slough i s a sodic s o i l , even though the EC of the s a t u r a t e d e x t r a c t i s over, a l b e i t s l i g h t l y , 4 dS/m. On the other hand, Houcher Lake wi t h an ESP of 19%, an EC of 5.03 dS/m, and a pH of only 7.5 i s probably s a l i n e - s o d i c . 102 S a l i n e - s o d i c s o i l s can be lumped wi t h the sodic s o i l s f o r management purposes, because of the d e f l o c c u l a t i n g i n f l u e n c e Na has on s o i l s . Sims et a l . (1984) found t h a t most sodic s p o i l s i n A l b e r t a are non-s a l i n e , or low i n t o t a l s a l t c o n c e n t r a t i o n (EC) . Man-made i s l a n d s i n Saskatchewan, i n c o n t r a s t to t h i s study, were c l a s s i f i e d p r i m a r i l y as s a l i n e and s a l i n e - s o d i c (Hamm 1982). In general, s o i l s a l i n i t y , i n c l u d i n g s o d i c i t y , i s a major problem i n the a g r i c u l t u r a l areas of the ' Canadian p r a i r i e s , and a d i s c u s s i o n of some of the causes and sources of s a l i n i t y i s a p p l i c a b l e to i s l a n d r e c l a m a t i o n . On a g r i c u l t u r a l lands the s a l t sources are e i t h e r s a l i n e seeps or are inherent i n the mineralogy of the parent m a t e r i a l ( P r a i r i e Farm R e h a b i l i t a t i o n A d m i n i s t r a t i o n 1983). 103 Figure 5. Photograph of sodic Hebert Lake i s l a n d . The bare patches of s o i l s e parating bunches of f o x t a i l b a r l e y and t a l l wheatgrass are obvious. Yellow sweet c l o v e r i s a l s o v i s i b l e . This type of vegetation i s t y p i c a l of the sodic i s l a n d s , August 10, 1986. In A l b e r t a , bedrock and, to a l e s s e r degree, g l a c i a l t i l l are major s a l t sources. The s o l o n e t z i c s o i l s i n c e n t r a l A l b e r t a are commonly found on parent m a t e r i a l comprised of Edmonton o r i g i n deposits and a small percentage of Bearpaw shale (Bowser et a l . 1947). The bentonite and s a l t s present can have a strong p h y s i c a l i n f l u e n c e on the s o i l s . Through chemical, p h y s i c a l and b i o l o g i c a l weathering, the s a l t s are r e l e a s e d i n t o the s o i l from the rocks and minerals comprising the parent m a t e r i a l . In the study area, 104 n e u t r a l s a l t s , such as Ca, Mg and Na sulphate are dominant, although c h l o r i d e s and bicarbonates are u s u a l l y found i n small q u a n t i t i e s a l s o ( P r a i r i e Farm R e h a b i l i t a t i o n A d m i n i s t r a t i o n 1983). Once s a l t s are re l e a s e d they can be t r a n s p o r t e d by water t o discharge s i t e s , which may r e s u l t i n s o i l s a l i n i z a t i o n . S a l i n i z a t i o n can a l s o r e s u l t from i r r i g a t i o n p r a c t i c e s . Poor water q u a l i t y may s a l i n i z e the s o i l , and inadequate drainage may cause excessive evaporation from the s o i l s u r f a c e , r e s u l t i n g i n the d e p o s i t i o n of s a l t s on the su r f a c e . A g r i c u l t u r a l p r a c t i c e s , such as summer-fallowing, can aggravate the normal s a l i n i z a t i o n process by i n c r e a s i n g the p e r c o l a t i o n of water through the s o i l . In t h i s s i t u a t i o n , s a l t i s pi c k e d up and t r a n s p o r t e d as the water moves through the s o i l , r e s u r f a c i n g downslope as a s a l i n e seep. S o i l s a l i n i t y on e a r t h i s l a n d s a r i s e s i n ways s i m i l a r to those d e s c r i b e d f o r mainland s i t u a t i o n s . F i r s t , many p r a i r i e wetlands are t e r m i n a l or i s o l a t e d wetlands; consequently there i s seldom a steady through-flow of water. In most of the wetlands, run-off enters the wetland and then evaporates. This process concentrates the s a l t s i n the water and surrounding s h o r e l i n e . Since these wetlands are l o c a t e d i n an a g r i c u l t u r a l area, the m a j o r i t y of the uplands are c u l t i v a t e d and oft e n i n summer-fallow, thus a l l o w i n g g r e a t e r s a l t loads to accumulate i n the groundwater as i t 105 runs towards the b a s i n . Unfortunately, s o i l s dredged from these, waters r e t a i n much of the s a l t . Aggravating the s a l i n i z i n g process i s the c a p i l l a r y movement of water through the s o i l to the i s l a n d s u r f a c e . Once at the surface, the water evaporates and depos i t s s a l t s , s i m i l a r to the s a l i n e seeps which develop below summer-fallowed f i e l d s or near i r r i g a t i o n c a n a l s . C a p i l l a r y movement can occur throughout the i s l a n d , but the e f f e c t i t has on s o i l s a l i n i t y probably depends on the wetland's water l e v e l . I s l a n d s o i l s can a l s o be water s a t u r a t e d d u r i n g the s p r i n g r u n o f f and f l o o d , perhaps a l l o w i n g i s l a n d r e s a l i n i z a t i o n . C a p i l l a r y a c t i o n and evaporation as the water l e v e l drops could cause f u r t h e r d e p o s i t i o n of s a l t on the i s l a n d s o i l . In wetlands flooded w i t h freshwater, however,, s a l t s may a c t u a l l y be f l u s h e d out. I s l a n d s a l i n i t y r e f l e c t s the l o c a l s o i l s , parent m a t e r i a l and wetland drainage- A l l the p r o j e c t s , except Houcher F l a t and Lake, Louis Lake, and Paulgaard, R o l l y v i e w and Z i l k e Marshes are bordered by s o l o n e t z i c s o i l s high i n s a l t s . For example, EC and SAR l e v e l s are r e l a t i v e l y low (about 3.0 dS/m and 1.2, r e s p e c t i v e l y ) at Louis Lake, probably i n p a r t because i t d r a i n s c o n t i n u a l l y , a l l o w i n g the s a l t s t o be f l u s h e d . In a d d i t i o n , the s o i l s surrounding Louis Lake are sandy; sand g e n e r a l l y has, good drainage and does not h o l d c a t i o n s t i g h t l y . Waskwei Creek i s found amongst s o l o n e t z i c s o i l s , yet the i s l a n d , s o i l s are n e i t h e r 106 s a l i n e nor s o d i c . In t h i s case, the creek i s r e l a t i v e l y f r e s h and flows r e g u l a r l y through the wetland. Paulgaard Marsh, while not surrounded by s o l o n e t z i c s , l i k e l y r e c e i v e s l a r g e q u a n t i t i e s of s a l t from groundwater flow. Although i t i s on a stream course, the a r i d environment and high o u t l e t preclude r e g u l a r f l o o d i n g , and s a l t s can concentrate on, f o r example,. the i s l a n d s . R o l l y v i e w Marsh i s s i m i l a r t o Paulgaard - i t i s not bordered by s o l o n e t z i c s o i l s , but occurs i n an i s o l a t e d b a s i n ; consequently, s a l t s are concentrated and, i n t h i s case, the i s l a n d s o i l s are h i g h l y s o d i c . S o l o n e t z i c s o i l s surround Kingston Slough, a wetland w i t h poor drainage. Groundwater discharge and water evaporation concentrate the s a l t s i n t h i s b a s i n and on the i s l a n d s , as the sodic i s l a n d s o i l c o n d i t i o n s i n d i c a t e . Extreme a l k a l i n i t y (pH > 8.5) i s . a s s o c i a t e d w i t h and c h a r a c t e r i s t i c of sodic s o i l s , and i n p r a c t i c a l terms there i s l i t t l e d i f f e r e n c e between s o d i c i t y and a l k a l i n i t y . The r e s u l t s of the c o r r e l a t i o n a n a l y s i s confirm t h a t a l k a l i n i t y , i n a d d i t i o n t o s o d i c i t y , i s an important i n f l u e n c e on i s l a n d v e g e t a t i o n . A l k a l i n i t y exerted a strong negative i n f l u e n c e on v e g e t a t i v e growth i n 1985 and 1986, the former i n p a r t i c u l a r (Tables 6.14 and 6.15). In 1985 and 1986, pH w and pH c were both n e g a t i v e l y c o r r e l a t e d w i t h t o t a l f o l i a r cover. Stepwise m u l t i p l e c o r r e l a t i o n a n a l y s i s 'in 1985 i d e n t i f i e d pH w as one of three dependent v a r i a b l e s i n a r e l a t i o n s h i p 107 t h a t e x p l a i n e d 64% of the v a r i a t i o n i n i s l a n d f o l i a r cover. In 1986, stepwise c o r r e l a t i o n a n a l y s i s i d e n t i f i e d a four v a r i a b l e r e l a t i o n - s h i p , which i n c l u d e d pH w. Exchangeable Na and SAR, both i n d i c a t o r s of a l k a l i n i t y , were common v a r i a b l e s i n the equations i d e n t i f i e d by APC and stepwise analyses (Table 6.15). Much of the reclamation l i t e r a t u r e deals w i t h c o l l i e r y and metal mine s p o i l s — s p o i l s t h a t tend t o be h i g h l y a c i d i c , (e.g. pH = 3.0), not a l k a l i n e . There i s l i t t l e mention of. a c i d i t y problems i n the p r a i r i e reclamation l i t e r a t u r e ; however, numerous s t u d i e s i d e n t i f y a l k a l i n i t y and s o d i c i t y as major problems. Sims et a l . (1984) reviewed some of the p r a i r i e reclamation work and considered pH 8.9 to be an extreme l e v e l of a l k a l i n i t y . High pH values are t y p i c a l f o r sodic s o i l s and s p o i l s because the exchangeable Na hydrolyzes. P a r t i c u l a r l y high pH values (>8.5) r e s u l t when sodium carbonate hydrolyzes and g r e a t l y i n c r e a s e s the hydroxyl ions i n s o l u t i o n . S o d i c i t y , or a l k a l i n i t y , i s harmful to p l a n t s because of the c a u s t i c e f f e c t from the hydroxyl ions, the t o x i c e f f e c t of the anions, and the d e t r i m e n t a l e f f e c t high a l k a l i n i t y has on n u t r i e n t a v a i l a b i l i t y and p l a n t metabolism ( R u s s e l l 1973). For example, pH l e v e l s between 7 and 9 reduce P s o l u b i l i t y and uptake by p l a n t s , and above pH 7 Ca and Mg begin to p r e c i p i t a t e , making them u n a v a i l a b l e to p l a n t s . Four of the 5 i s l a n d s c l a s s i f i e d as sodic had pH values over 9.0: Hebert Lake, Kingston Slough, Paulgaard and 108 R o l l y v i e w Marshes. These i s l a n d s t y p i c a l l y had a c r u s t e d , bare surface, as the negative c o r r e l a t i o n between a l k a l i n i t y and cover i n d i c a t e s . Drainage from these a l k a l i n e sloughs was n i l or minimal. Because of the harsh environment a l k a l i n e s o i l s provide f o r p l a n t l i f e , a l i m i t e d number of species can e s t a b l i s h . On the i s l a n d s i n the four wetlands, two species were dominant: t a l l wheatgrass and f o x t a i l b a r l e y (Table 6.3). (Although intermediate wheatgrass, not t a l l wheatgrass, i s present on Kingston Slough i s l a n d s , the two species have extremely s i m i l a r e c o l o g i c a l niches, are m o r p h o l o g i c a l l y s i m i l a r , and seem to be a c t i n g the same p h y s i o l o g i c a l l y . ) These species were found on other i s l a n d s , but nowhere e l s e were they dominant. S a l t meadow grass i s a l s o t o l e r a n t of a l k a l i n e c o n d i t i o n s . I t was found i n r e l a t i v e abundance on Kingston Slough i s l a n d s only. Sodium s a l t s i n the s o i l have a d e t r i m e n t a l e f f e c t , on s o i l p h y s i c a l s t r u c t u r e . Excessive Na i n the s o i l prevents aggregate formation and creates s o i l p h y s i c a l problems. S o d i c - a l k a l i n e s o i l s d e f l o c c u l a t e and d i s p e r s e when wet, thus reducing the a e r a t i o n p o r o s i t y , l i m i t i n g i n f i l t r a t i o n , and g r e a t l y decreasing the h y d r a u l i c c o n d u c t i v i t y of the s o i l . These s o i l s a l s o s w e l l when wet and form an e f f e c t i v e surface s e a l , preventing water from e n t e r i n g the r o o t i n g zone. Sims et a l . (1984) considers s o d i c i t y the main cause of low i n f i l t r a t i o n r a tes i n A l b e r t a s p o i l s . I f r a i n f a l l exceeds the i n f i l t r a t i o n r a t e , then water accumulates on the s o i l surface and begins to run o f f 109 overland. Surface run-off c o n t r i b u t e s to e r o s i o n , and may shorten an i s l a n d ' s l i f e - s p a n s i g n i f i c a n t l y . Sims et a l . (1984) recommended th a t reclamation of a s p o i l be completed as soon as p o s s i b l e because they tend to s e t t l e w i t h time, lowering the i n f i l t r a t i o n r a t e and i n c r e a s i n g BD. I n f i l t r a t i o n r a t e s t y p i c a l l y are greater on graded than ungraded s p o i l s (Sims et a l . 1984). Sodic, or a l k a l i n e , s o i l s are a l s o prone t o puddling during r a i n s . Puddling reduces pore space and compacts the s o i l , thereby i n c r e a s i n g BD and reducing i n f i l t r a t i o n r a t e s ( C u r t i s 1973). Puddling can occur whenever a f o r c e i s a p p l i e d to the s o i l t h a t causes the c l a y p a r t i c l e s to r e o r i e n t from a random p a t t e r n to p a r a l l e l . Pore space i s reduced at the same time. For example, t r a c t o r t i r e s puddle s o i l s . Because s o i l s are p a r t i c u l a r l y s u s c e p t i b l e t o puddling when wet, puddling l i k e l y occurs dur i n g i s l a n d c o n s t r u c t i o n , when the wetland bottom sediment i s dredged and p i l e d . The f o r c e a p p l i e d to the wet s o i l when p i l i n g i s probably s u f f i c i e n t to cause puddling. Ponding i s another consequence of puddled s o i l and high s o d i c i t y . Ponding r e f e r s to the s i t u a t i o n where water accumulates, on the s o i l surface w i t h unsaturated s o i l l y i n g between the s o i l surface and the water t a b l e . Ponded water was commonly found on i s l a n d s , e s p e c i a l l y those w i t h sodic s o i l s , e.g. R o l l y v i e w Marsh and Kingston Slough i s l a n d s . Observations were made of pl a n t e d shrubs on these i s l a n d s dying from a lack of water when they were s i t t i n g near pools 110 of ponded water. Of course, the s a l t c o n c e n t r a t i o n of the s o i l a l s o reduces water a v a i l a b i l i t y , l e a v i n g many p l a n t s near the permanent w i l t i n g p o i n t . H y d r a u l i c c o n d u c t i v i t y (HC), which r e f e r s to how r e a d i l y water flows through s o i l , tends t o be i n v e r s e l y r e l a t e d w i t h ESP (Sims et a l . 1984) . Although HC was not measured, steady-state i n f i l t r a t i o n was measured on a l l i s l a n d s and appears i n v e r s e l y r e l a t e d t o ESP. Kingston Slough and R o l l y v i e w Marsh had the g r e a t e s t ESP (67% and 89%, r e s p e c t i v e l y ) (Table 6.9), and the lowest i n f i l t r a t i o n r a t e s (< 0.1 cm/hour) (Table 6.13). By comparison, Louis Lake i s l a n d s had r e l a t i v e l y good i n f i l t r a t i o n and a low ESP (3.3%) . Although the r e l a t i o n s h i p between i n f i l t r a t i o n r a t e and ESP ( s o d i c i t y ) . i s strong, other f a c t o r s , such as s o i l t e x t u r e and compaction, a l s o a f f e c t i n f i l t r a t i o n . Paulgaard Marsh, f o r example, with an ESP of 65%, has r e l a t i v e l y good i n f i l t r a t i o n (8.0 cm/hour). This i s a t t r i b u t a b l e to the high percentage of sand i n the s o i l , which increases macropore volume and i s not a f f e c t e d by Na s a l t s . By c o n t r a s t , Waskwei Creek i s l a n d , w i t h low Na, has r e l a t i v e l y poor i n f i l t r a t i o n (0.5 cm/hour). In t h i s case low i n f i l t r a t i o n i s probably a t t r i b u t a b l e t o low a e r a t i o n p o r o s i t y and r e l a t i v e l y high c l a y (42%, Table 6.12). Sodium-affected s o i l s a l s o develop s t r u c t u r a l problems when dry. Upon d r y i n g , sodic s o i l s s h r i n k and crack, and surface c r u s t s form. The l a t t e r c o n d i t i o n i n h i b i t s s e e d l i n g 111 establishment, while the former can open the surface s o i l l ayer, exposing the roots. Establishing vegetation under these sodic conditions i s d i f f i c u l t because i r r i g a t i o n causes s o i l swelling, which exacerbates shrinking and cracking problems. Bentonite clay, prevalent throughout the Edmonton formation, i s a 1:2 swelling clay prone to swelling and shrinking. Because bentonite i s a common constituent of s o i l s i n the study area, the i s l a n d s o i l s l i k e l y contain t h i s c l a y . Its presence can aggravate s o i l physical problems. The f i n a l major factor influencing i s l a n d vegetation i s a physical property: bulk density (BD). Bulk density i s a physical property of s o i l and i s defined as the dry mass of s o i l per unit t o t a l (or bulk) volume. It provides a measure of s o i l compaction and porosity. Bulk density was highly negatively correlated with t o t a l f o l i a r cover i n 1985 and 1986 (Tables 6.14 and 6.15). In 1985, BD alone explained almost hal f ( r2 = 0.47) of the v a r i a b i l i t y i n plant cover; i n 198 6 i t explained about one t h i r d ( r2 = 0.32). Bulk density was included i n most of the two-, three- and four-variable equations selected by APC c o r r e l a t i o n a n a l y s i s . Further, i n both years BD was one of a combination of factors i d e n t i f i e d by stepwise c o r r e l a t i o n analysis that influenced i s l a n d vegetation (Table 6.15). S o i l s with high BD tend to have poor structure and p o r o s i t y . In contrast, low BD s o i l s are very porous and 112 u s u a l l y have good s t r u c t u r e . The bulk d e n s i t y of organic s o i l s may be only 300 kg/m3, whereas compacted s o i l s or s o i l s r i c h i n i r o n can reach more than 2000 kg/m3. The bulk d e n s i t y of most a g r i c u l t u r a l s o i l s l i e s between 1000 and 1600 kg/m3. Bulk d e n s i t y of the study i s l a n d s v a r i e d widely, from 300 t o 1600 kg/m3 and averaging 1100 kg/m3 (Table 6.11). The four s o d i c i s l a n d s - Hebert Lake, Kingston Slough, and Paulgaard and R o l l y v i e w Marshes - had the highest BD value s . A l l were c l o s e to 1500 kg/m3, although i n 1986 Kingston Slough and R o l l y v i e w Marsh s o i l BDs were c l o s e t o 1600 kg/m3. Bulk d e n s i t y values f o r Louis Lake i s l a n d were between 300 and 500 kg/m3, comparable to organic s o i l s . F o l i a r cover was a l s o greatest on t h i s i s l a n d . Louis Lake s o i l had good crumb s t r u c t u r e and was easy t o work with, whereas the sodic i s l a n d s were hard and cloddy when dry. The e f f e c t of heavy equipment on BD has been n o t i c e d by many authors (Sims et a l . 1984). Although a l l the i s l a n d s were made wit h heavy equipment by dredging and p i l i n g , i s l a n d BD and p l a n t cover v a r i e d . Bulk d e n s i t y l e v e l s of rec o n s t r u c t e d mine s o i l s i n I l l i n o i s were between 1310 and 1590 kg/m3, whereas undisturbed s i l t loam s o i l s were between 1320 and 1340 kg/m3 (Indorante et a l . 1981) . The re c o n s t r u c t e d s o i l s had been reclaimed u s i n g heavy equipment. The.movement of heavy equipment and the handling of the s o i l , both of which can destroy aggregates, probably c o n t r i b u t e d to the increased BD. Two s i l t loam s o i l s found 113 under hardwood f o r e s t s i n Indiana had BD's of 1290 and 1390 kg/m3, whereas the adjacent mined-land s o i l was 1540 kg/m3 (Bussler et a l . 1984). In a study of s o i l compaction by c a t t l e the BD on ungrazed land was 1350 kg/m3, wit h normal g r a z i n g (10 ca t t l e / h a ) i t increa s e d t o 1440 kg/m3 and under heavy g r a z i n g (40 c a t t l e / h a ) i t increa s e d f u r t h e r t o 1530 kg/m3 (Stephenson and V i e g e l 1987) . Po o r l y vegetated i s l a n d s (Figures 4 and 5) tended to have high BD l e v e l s , as the negative c o r r e l a t i o n i n d i c a t e s ; however,, i n general, areas w i t h high BD can s t i l l be w e l l vegetated. In c r e a s i n g s o i l bulk d e n s i t y i s u s u a l l y a r e s u l t of decreasing pore space; however, the r e l a t i o n s h i p between BD and p o r o s i t y i s complex and more i n f o r m a t i o n i s r e q u i r e d to f u l l y e x p l a i n the e f f e c t s BD and p o r o s i t y have on p l a n t growth, and water and a i r movement through s o i l . P o r o s i t y r e f e r s to the space between and w i t h i n s o i l aggregates. The wa t e r - r e t e n t i o n pores can h o l d water against g r a v i t y and p l a n t s can use t h i s s t o r e d water. A e r a t i o n pores c o n t r i b u t e to gas exchange and water i n f i l t r a t i o n and drainage. I d e a l l y , f o r example i n good loam s o i l , h a l f of the s o i l bulk volume i s pore space, which i t s e l f i s d i v i d e d e q u a l l y i n t o w a t e r - r e t e n t i o n and a e r a t i o n p o r o s i t y . Sand has e x c e l l e n t drainage because of the good a e r a t i o n p o r o s i t y between sand g r a i n s ; however, i t l a c k s the sma l l e r pores t h a t r e t a i n water and consequently sandy s o i l i s droughty. 114 S o i l w i t h poor s t r u c t u r e may la c k s u f f i c i e n t t o t a l pore space or be d e f i c i e n t i n j u s t one type, as i s the case w i t h most i s l a n d s o i l s . Puddled i s l a n d s o i l s had r e l a t i v e l y normal BD (about 1100 kg/m 3), but s o i l compression during c o n s t r u c t i o n r e s u l t e d i n low a e r a t i o n pore space (11.1% average)(Table 6.12). T o t a l p o r o s i t y on the study i s l a n d s averaged 59.2%, which i s good, si n c e 50% i s the management o b j e c t i v e . A e r a t i o n p o r o s i t y l e v e l s on the i s l a n d s were very low (Table 6.12), the highest being only 18.9% of the t o t a l volume (on Louis Lake i s l a n d ) . Lower p o r o s i t y seems t o be common i n d i s t u r b e d s o i l s . A e r a t i o n p o r o s i t y of mined-land s o i l i n Indiana was < 5%, compared to 6 and 10% f o r two s i l t loam s o i l s from an unmined reference area. A l l three values are r e l a t i v e l y low (Bussler et a l . 1984). On i s l a n d s , l i k e Louis Lake wi t h high t o t a l p o r o s i t y , low a e r a t i o n p o r o s i t y i s s u f f i c i e n t f o r p l a n t growth. However, at Kingston Slough, with 47% t o t a l p o r o s i t y , a e r a t i o n p o r o s i t y comprised only 5.4% of the t o t a l volume. This l e v e l i s f a r below the 25% optimum so i t i s not s u r p r i s i n g t h a t the i n f i l t r a t i o n r a t e was extremely poor (< 0.1 cm/h). Although Paulgaard Marsh had high BD (1400 kg/m3) and low a e r a t i o n p o r o s i t y (10%), the i n f i l t r a t i o n r a t e was 8 cm/h i n 1986, compared to < 0.1 cm/h at Kingston Slough. The higher Paulgaard Marsh r a t e i s l i k e l y a t t r i b u t a b l e t o i t s r e l a t i v e l y sandy s o i l . 115 T o t a l p o r o s i t y was probably overestimated because of the prevalence of small cracks i n the s o i l cores. Many of the cracks were a r t i f a c t s of sampling and would be measured as a e r a t i o n pores. Even w i t h these cracks, however, the ae r a t i o n p o r o s i t y was poor. I s l a n d a e r a t i o n p o r o s i t y and i n f i l t r a t i o n are probably i n f l u e n c e d by the cracks and holes i n the i s l a n d s t h a t develop from i s l a n d slumping, water e r o s i o n and muskrat burrows. Most of the water t h a t runs o f f through these holes probably reaches the water t a b l e and i s not a v a i l a b l e f o r shallow rooted p l a n t s and s e e d l i n g s . Surface water r u n o f f aggravates the cracks. An important s o i l f a c t o r a l l u d e d t o above i s organic matter. Hamm (1982) considered organic matter second only to s a l i n i t y , i n i t s e f f e c t on veg e t a t i o n establishment on DU i s l a n d s . Organic matter reduces BD, improves aggregation, and, t h e r e f o r e , s o i l s t r u c t u r e , a e r a t i o n and i n f i l t r a t i o n . U l t i m a t e l y i t provides n u t r i e n t s f o r p l a n t use a l s o . Hamm (1982) emphasized the importance organic matter p l a y s i n am e l i o r a t i n g the e f f e c t s of s o i l s a l i n i t y . Organic carbon was measured and used as an index f o r organic matter. Organic carbon i s commonly converted to organic matter by m u l t i p l y i n g % C by 1.724 (Black 1965). Organic carbon was p o s i t i v e l y c o r r e l a t e d w i t h t o t a l f o l i a r cover i n 1985 and 1986 (Table 6.14). Carbon was not an important v a r i a b l e i n the m u l t i p l e c o r r e l a t i o n analyses run on 1985 and 1986 data (Table 6.15). In 1986, however, C had 116 the second strongest r e l a t i o n s h i p w i t h t o t a l cover, a f t e r BD. Of course the importance of C i s a l s o r e f l e c t e d by the importance of i s l a n d BD. Carbon was n e g a t i v e l y c o r r e l a t e d (P < 0.001) wi t h BD i n both years. The sodic i s l a n d s -Hebert Lake, Kingston Slough, and Paulgaard and R o l l y v i e w Marshes - a l l had low (< 1%) C l e v e l s , as the high BD i n d i c a t e s . In general, the b e t t e r vegetated i s l a n d s had higher C l e v e l s , f o r example, Louis Lake and Z i l k e Marsh had above average C l e v e l s . Organic C averaged about 3.0% i n 1985 and 3.4% i n 1986 (Table 6.10). Compared t o other reclamation s t u d i e s , these C values are high, and c o i n c i d e w i t h the high t o t a l p o r o s i t y measurements. On surface-mined s o i l s i n I l l i n o i s organic C values ranged from 0.2 t o 0.9% (Indorante et a l . 1981). Organic C on re c o n s t r u c t e d mine s o i l i n Indiana was between 1.0 and 1.8% (Bussler et a l . 1984) . Although the i s l a n d C l e v e l s are high, s e v e r a l c o n d i t i o n s suggest t h a t they could be misle a d i n g i n terms of q u a l i t y , and they probably confound the c o r r e l a t i o n analyses. From f i e l d observations and the BD and i n f i l -t r a t i o n data, i t appears t h a t much of the organic m a t e r i a l i s i n a coarse or undecomposed s t a t e . During c o n s t r u c t i o n , a q u a t i c p l a n t s are dredged up with the bottom sediment and in c o r p o r a t e d i n t o the i s l a n d without mulching; consequently, the organic m a t e r i a l i s l e s s e f f e c t i v e than the high values would suggest. In a d d i t i o n , Louis Lake i s l a n d has an extremely high C content which i n f l a t e s the 117 o v e r a l l mean. S o i l s are considered organic when they reach 17% C, and Louis Lake f a l l s j u s t short at 13% (22% organic matter) . E x c l u d i n g the Louis Lake r e s u l t s , the mean i s c l o s e t o 2% C, comparable to mineral s o i l r e s u l t s elsewhere. Over time the organic m a t e r i a l w i l l decompose and c o n t r i b u t e more to aggregate s t a b i l i t y and development, and consequently improve a e r a t i o n , i n f i l t r a t i o n and water-r e t e n t i o n . Nestingboard Method Throughout t h i s document t o t a l f o l i a r cover has r e f e r r e d t o f o l i a r cover measured using the p o i n t - i n t e r c e p t method. Although t h i s method i s commonly used i n g r a s s l a n d and pasture s i t u a t i o n s , there are other methods considered s u p e r i o r f o r p a r t i c u l a r purposes. For example p l a n t biomass i s o f t e n used i n the study of rangelands (Munn et a l . 1978) . Nestingboards are commonly used by w i l d l i f e agencies seeking to assess v e g e t a t i o n s u i t a b i l i t y f o r waterfowl and upland gamebirds (Jones 1968). For t h i s study, a Ducks U n l i m i t e d Canada nestingboard provided a second measure of i s l a n d f o l i a r cover against which environmental v a r i a b l e s c ould be compared. As such, i t serves as a check on the primary method. I t a l s o allows a comparison to be made between t h i s common f i e l d method and the more s p e c i f i c and labour i n t e n s i v e p o i n t - i n t e r c e p t method. A strong r e l a t i o n s h i p e x i s t s between the v e g e t a t i v e cover data generated by the two methods (1985: r 2 = 0.64, 118 P < 0.001, n = 142). The p o i n t - i n t e r c e p t method measures the f o l i a r cover from a v e r t i c a l or overhead p e r s p e c t i v e , whereas, the p e r s p e c t i v e measured by the nestingboard i s c l o s e r to h o r i z o n t a l . Given these d i f f e r e n c e s the r 2 i s s u r p r i s i n g l y high. Simple c o r r e l a t i o n a n a l y s i s revealed t h a t nestingboard and p o i n t - i n t e r c e p t cover had s i m i l a r r e l a t i o n s h i p s w i t h the environmental v a r i a b l e s . In 1985, a l l v a r i a b l e s , except Mg and slope, c o r r e l a t e d w i t h t o t a l f o l i a r ( p o i n t - i n t e r c e p t ) cover were a l s o c o r r e l a t e d w i t h nestingboard cover (Table 6.14) . In 1986, 10 of 14 v a r i a b l e s a s s o c i a t e d w i t h t o t a l f o l i a r cover were a l s o a s s o c i a t e d w i t h nestingboard cover (Table 6.14). V a r i a b l e s c o r r e l a t e d w i t h t o t a l f o l i a r cover only, i n c l u d e d a e r a t i o n p o r o s i t y , pH, and s o l u b l e Mg. Soluble Na was c o r r e l a t e d w i t h nestingboard cover only. D i f f e r e n c e s i n r e s u l t s were expected and can probably be a t t r i b u t e d t o the d i f f e r e n t method of v e g e t a t i o n sampling, which measures a d i f f e r e n t type of p l a n t cover. As w i t h t o t a l f o l i a r cover, BD and exchangeable Na are important p r e d i c t o r v a r i a b l e s of nestingboard cover. Nestingboard cover a l s o responded i n both years to t o t a l N, exchangeable Ca and C (Table 6.14). These r e s u l t s i n d i c a t e t h a t i s l a n d v e g e t a t i v e cover, r e g a r d l e s s of the method of measurement, i s i n f l u e n c e d by the l e v e l of s o i l compaction and s o d i c i t y . A l k a l i n i t y i s a l s o important, even though i t was not i d e n t i f i e d f o r nestingboard cover i n 1986. 119 Multiple c o r r e l a t i o n analysis of the nestingboard data yielded a combination of predictor variables s i m i l a r to those for t o t a l f o l i a r cover (Table 6.15). Bulk density and exchangeable Na were part of both subsets i n 1985; however, pHw was an important determinant of t o t a l f o l i a r cover, whereas i n f i l t r a t i o n (median) was important to nestingboard cover. Again the importance of s o i l compaction, porosity and s o d i c i t y comes through. In 1986 the inte r p r e t a t i o n i s more complex. Three of four variables important to t o t a l f o l i a r cover are also important to nestingboard cover: exchangeable Na, pHc and EC. Height-above-water and i n f i l t r a t i o n , rather than BD, were also part of the re l a t i o n s h i p with nestingboard cover. Although d i f f e r e n t variable combinations influence the two measures of i s l a n d vegetative cover, the strong s i m i l a r i t i e s indicate that they respond s i m i l a r l y to environmental pressures. Even though some of the cor-r e l a t i v e variables were d i f f e r e n t , they are often i n d i c a t i v e of s i m i l a r problems. For example, low i n f i l t r a t i o n and high BD both r e f l e c t s o i l physical problems. 120 D. OTHER MEASURES OF FOLIAR COVER To determine the general response of seeded species to the s o i l and s i t e c o n d i t i o n s , t o t a l f o l i a r cover was d i v i d e d i n t o seeded and nonseeded cover. The former measure was c a l c u l a t e d from the pin-drops h i t t i n g species p l a n t e d on the i s l a n d s by DU (p. 43; Appendix 1). The remainder were c l a s s i f i e d as nonseeded spec i e s . Although i s l a n d f l o r a v a r i e d c o n s i d e r a b l y w i t h i n and between wetlands, i n general, nonseeded species tended to be dominant. Seeded and nonseeded coverage averaged about 20% and 30% r e s p e c t i v e l y , i n 1985 and 1986. On some i s l a n d s , such as Waskwei Creek, • seeded species were predominant, whereas on others, f o r example Louis Lake, n a t i v e species were predominant (Appendix 3). The response of both seeded and nonseeded f o l i a r cover to environmental c o n d i t i o n s was s i m i l a r to tha t of t o t a l f o l i a r cover. In 1985, both cover components responded n e g a t i v e l y to low p o r o s i t y , compacted s o i l and sodic c o n d i t i o n s (Table 6.16). Nonseeded cover responded n e g a t i v e l y t o a l k a l i n i t y and compaction i n 1986 a l s o . These r e l a t i o n s h i p s show up c l e a r l y i n the simple and m u l t i p l e c o r r e l a t i o n analyses (Tables 6.16 and 6.17). Oddly, i n 1986, seeded cover was not c o r r e l a t e d w i t h any s o i l or s i t e v a r i a b l e . Even m u l t i p l e c o r r e l a t i o n a n a l y s i s y i e l d e d no s i g n i f i c a n t v a r i a b l e or combination of v a r i a b l e s . A number of p o s s i b i l i t i e s c o uld c o n t r i b u t e to t h i s response. The various seeded species p o s s i b l y 121 responded d i f f e r e n t l y t o the 1986 c o n d i t i o n s , making g e n e r a l i z a t i o n s , f o r example i n the form' of a c o r r e l a t i o n c o e f f i c i e n t , d i f f i c u l t . There i s , of course, no b i o l o g i c a l reason why a l l the seeded species should respond s i m i l a r l y . Some species are dicotyledonous, others monocotyledonous; some were developed f o r dry, s a l i n e c o n d i t i o n s , such as t a l l wheatgrass, whereas others were developed f o r moist, n e u t r a l c o n d i t i o n s , e.g. creeping red fescue. A l s o , heavy r a i n f a l l i n 1986, e s p e c i a l l y i n comparison to the r a i n f a l l i n 1985, may have ameliorated some of the adverse s o i l c o n d i t i o n s , i n p a r t i c u l a r a l k a l i n i t y and s o d i c i t y . Despite the 1986 lack of response of seeded species,, the groupings r e i n f o r c e the c o n s t r a i n t s s o d i c i t y and p h y s i c a l s t r u c t u r e impose on a l l p l a n t s , seeded or not. Grouping seeded species may enable the d e t e c t i o n of problems a s s o c i a t e d w i t h seedbed p r e p a r a t i o n and seeding. Although seeding problems were not i d e n t i f i e d d i r e c t l y , the recurrence of compaction and p o r o s i t y as c o r r e l a t i v e v a r i a b l e s i n d i r e c t l y p o i n t s t o a poor seedbed. In 1985, a strong r e l a t i o n s h i p e x i s t e d between height-above-water and ve g e t a t i v e f o l i a r cover: n e g a t i v e l y c o r r e l a t e d w i t h nonseeded species cover and p o s i t i v e l y c o r r e l a t e d with seeded species (Table 6.17). Along w i t h measures of p o r o s i t y and s o d i c i t y , height-above-water was a l s o important i n the m u l t i p l e c o r r e l a t i o n r e s u l t s (Table 6.18). The negative response of nonseeded species to height i s r e f l e c t e d by the r e l a t i v e l y l u s h i s l a n d s h o r e l i n e p l a n t 122 growth. This zone i s w i t h i n or c l o s e t o the c a p i l l a r y f r i n g e and u s u a l l y supports vigourous stands of s h o r e l i n e and emergent species, f o r example t a l l manna grass, sedges, slough grass, and numerous f o r b s . Moving inwards from the s h o r e l i n e , the i s l a n d s o i l c o n d i t i o n s become d r i e r and do not support these s p e c i e s . Seeded speci e s , however, are chosen to grow i n the d r i e r areas; consequently they g e n e r a l l y responded p o s i t i v e l y to height-above-water. Nonseeded species grow on the i s l a n d tops a l s o , but not i n the homogeneous stands found near the water. Because of the manner of species s e l e c t i o n , the i n f l u e n c e height appears t o have on seeded and nonseeded ve g e t a t i o n can be considered an a r t i f a c t of management. T o t a l f o l i a r cover was a l s o d i v i d e d i n t o f o r b and graminoid f o l i a r cover. The former category r e f e r s to broad-leafed or dicotyledonous p l a n t s , whereas the l a t t e r r e f e r s to grass and g r a s s - l i k e , or monocotyledonous p l a n t s , i n c l u d i n g , f o r example, sedges and rushes (Juncus spp.). Both groupings responded s i g n i f i c a n t l y t o the s o d i c , a l k a l i n e and compacted s o i l c o n d i t i o n s (Tables 6.18 and 6.19) . Graminoid and forb cover i n 1985, and forb cover, i n 1986 i n p a r t i c u l a r , were s t r o n g l y a s s o c i a t e d w i t h v a r i a b l e s such as pH, - BD and Na. In 1985, stepwise c o r r e l a t i o n of f o r b cover y i e l d e d a set of v a r i a b l e s (-BD, - p H c & -Na) almost i d e n t i c a l to the stepwise a n a l y s i s of t o t a l f o l i a r cover i n 1985 and 1986 (Table 6.15). Graminoid cover i n 1986, however, was c o r r e l a t e d with only one v a r i a b l e : 123 height-above-water. This lack of s i g n i f i c a n c e i s s i m i l a r to seeded cover i n 1986, when i t was not c o r r e l a t e d w i t h any v a r i a b l e s . The s i m i l a r i t y of response between graminoid and seeded cover may be a t t r i b u t a b l e t o the number of seeded species t h a t are grasses, f o r example the wheatgrasses ( t a l l , intermediate and c r e s t e d ) , creeping red fescue and smooth brome grass. Whitetop grass and f o x t a i l b a r l e y are the only common nonseeded grasses. In c o n t r a s t , the forb species are dominated by p e r e n n i a l weeds such as Canada t h i s t l e and sow t h i s t l e . Yellow sweet c l o v e r was the only common seeded f o r b . Graminoid cover, however, was n e g a t i v e l y c o r r e l a t e d w i t h height-above-water i n 1985 and 1986; whereas seeded cover was p o s i t i v e l y c o r r e l a t e d with height-above-water i n 1985. This statement appears to c o n t r a d i c t the e a r l i e r e x p l a n a t i o n f o r s i m i l a r i t i e s between seeded and graminoid cover; however, the negative response may be a t t r i b u t a b l e to the graminoid species growing along the i s l a n d shore. The s h o r e l i n e species, such as sedges, rushes, and some grasses, tend to grow i n dense stands around the perimeter of the i s l a n d , t h i n n i n g out towards the middle of the i s l a n d . This r i n g of dense ve g e t a t i o n was obvi o u s l y s u f f i c i e n t t o produce an e f f e c t n e g a t i v e l y r e l a t e d w i t h height-above-water. Reasons f o r the i n c o n s i s t e n c y are probably s i m i l a r to those given to e x p l a i n the c o r r e l a t i o n r e s u l t s f o r seeded spec i e s . 124 E. INDIVIDUAL SPECIES COVER I n d i v i d u a l species f o l i a r cover and frequency v a r i e d c o n s i d e r a b l y . The i n f l u e n c e t h a t a l k a l i n i t y , s o d i c i t y and bulk d e n s i t y exerted on t o t a l f o l i a r cover was a l s o apparent on i n d i v i d u a l s p e c i e s . Over h a l f of the species were e i t h e r p o s i t i v e l y or n e g a t i v e l y c o r r e l a t e d w i t h p H ( c & W ) i n both 1985 and 1986. S i m i l a r l y , about 30% of the species were c o r r e l a t e d w i t h BD and exchangeable Na i n both years. Exchangeable Ca and EC were next i n importance. Although most species were a f f e c t e d by these v a r i a b l e s , the degree and type of i n f l u e n c e , whether p o s i t i v e or negative, v a r i e d among sp e c i e s . A l s i k e clover was p l a n t e d at Kingston Slough only, but was n e i t h e r recorded nor observed. Because t h i s species i s a s h o r t - l i v e d p e r e n n i a l , i t i s u n l i k e l y to have s u r v i v e d the s i x years between seeding and the s t a r t of t h i s study. Although t h i s legume i s noted f o r i t s a b i l i t y t o t o l e r a t e some f l o o d i n g and more a l k a l i n e c o n d i t i o n s than other legumes (Walton 1983), i t probably could not withstand the severe a l k a l i n i t y and s o d i c i t y of Kingston Slough i s l a n d s . The l i m i t of i t s s a l t t o l e r a n c e was reported to be 2 t o 4 dS/m (White and de Jong 1975), and Kingston Slough satEC was 4.6 dS/m i n 1986. A l f a l f a i s the most widely grown forage species i n A l b e r t a and the world (Walton 1983). Despite these c r e d i t s i t was the l e a s t frequent of the seeded (and most nonseeded) species recorded (Table 6.1). I t s frequency was 15% i n 125 1985, and only 6% i n 1986. A l f a l f a f o l i a r cover was a l s o very low (< 1%) (Table 6.2). Further, no environmental v a r i a b l e s were c o r r e l a t e d with i t i n e i t h e r year. The reasons f o r a l f a l f a ' s l a c k of success appear obvious. F i r s t , a l f a l f a i s not t o l e r a n t of s a l i n e or a l k a l i n e s o i l s , e s p e c i a l l y at the germination stage (White and deJong 1975), preventing establishment on s e v e r a l i s l a n d s . Second, on more s a l i n e - and alkaline-moderate i s l a n d s i t probably cannot s u r v i v e competition w i t h other p e r e n n i a l weeds (e.g. Canada and sow t h i s t l e ) or grasses. Good stands of a l f a l f a have been observed on i s l a n d s , but only on southern A l b e r t a i s l a n d s where t o p s o i l was p l a c e d on the i s l a n d s u r f a c e . Islands b u i l t w ith a backhoe i n flooded basins would l i k e l y r e q u i r e i n t e n s i v e management f o r a l f a l f a t o be s u c c e s s f u l . Yellow sweet clover i s a b i e n n i a l , t a l l - g r o w i n g legume adapted to a wide range of s o i l c o n d i t i o n s . Depending on where i t i s found i t i s considered e i t h e r harmful or b e n e f i c i a l . I t i s o f t e n used f o r reclamation and s o i l b u i l d i n g because i t has a deep taproot and f i x e s N. In 1985, i t was the f o u r t h most frequent species (53%) and was number one i n terms of f o l i a r cover (12.6% on I s l a n d Nos. 1) (Tables 6.1 and 6.2). I t s frequency (41%) ranked seventh, and i t s cover f o u r t h (6.6%) i n 1986. The d e c l i n e i n frequency and cover from 1985 t o 198 6 i s a t t r i b u t a b l e to the b i e n n i a l nature of sweet c l o v e r . In 1985, the c l o v e r on most i s l a n d s was i n i t s f l o w e r i n g stage, growing t o a height 126 of 0.5 to 1.0 m or more i n some pl a c e s . During the veg e t a t i v e stage, as i n 1986, yellow sweet c l o v e r r a r e l y reached 0.5 m high, and probably averaged h a l f t h a t . Yellow sweet c l o v e r tended to form dense stands even during the sho r t e r , v e g e t a t i v e stage (Figure 6). Figure 6. Yellow sweet c l o v e r on Z i l k e Marsh i s l a n d . This species dominated the veg e t a t i o n on Z i l k e Marsh i s l a n d , August 4, 1986. In places i t grew to > 1 m i n height. In 1985, sweet c l o v e r cover responded n e g a t i v e l y to a l k a l i n i t y (pH w), s o d i c i t y and compaction - s i m i l a r to many other species (Table 6.31). I t al s o p r e f e r r e d the higher p a r t s of the i s l a n d s . In f a c t , m u l t i p l e c o r r e l a t i o n i d e n t i f i e d the best r e l a t i o n s h i p to be between yellow sweet 127 c l o v e r c o v e r a n d e x c h a n g e a b l e C a a n d h e i g h t - a b o v e - w a t e r . I n 1986, e x c h a n g e a b l e C a w a s i m p o r t a n t a g a i n , t o g e t h e r w i t h s o l u b l e a n d e x c h a n g e a b l e M g . E x c h a n g e a b l e M g a l o n e p r o v i d e d t h e b e s t r e l a t i o n s h i p i n 1986. Y e l l o w s w e e t c l o v e r g r o w s b e s t o n c a l c a r e o u s s o i l s ( T u r k i n g t o n e t a l . 1978), a s t h e r e s u l t s a t t e s t . A l t h o u g h i t s c o v e r d e c l i n e d w i t h i n c r e a s i n g s o d i c i t y o n t h e i s l a n d s , y e l l o w s w e e t c l o v e r i s c o n s i d e r e d m o d e r a t e l y s a l t t o l e r a n t a n d h a s b e e n r e c o m m e n d e d e l s e w h e r e f o r u s e o n s o d i c a n d a l k a l i n e s p o i l s ( W a t s o n e t a l . 1980). Y e l l o w s w e e t c l o v e r ' s r e s p o n s e t o t h e a l k a l i n e c o n d i t i o n s m a y b e p a r t i a l l y r e l a t e d t o n u t r i e n t d e f i c i e n c i e s t h a t o f t e n d e v e l o p u n d e r h i g h p H c o n d i t i o n s . F o r e x a m p l e , y e l l o w s w e e t c l o v e r h a s a h i g h e r r e q u i r e m e n t f o r P t h a n m o s t g r a s s e s , a n d P i s . a n u t r i e n t t h a t b e c o m e s u n a v a i l a b l e U n d e r a l k a l i n e c o n d i t i o n s . C a l c i u m a n d Mg a l s o b e c o m e l e s s a v a i l a b l e u n d e r h i g h p H . A l t h o u g h y e l l o w s w e e t c l o v e r r o o t n o d u l e s w e r e n o t f o u n d , a n e g a t i v e c o r r e l a t i o n w i t h N w a s i d e n t i f i e d i n a 1986 s t e p w i s e c o r r e l a t i o n r e s u l t w h i c h i n c l u d e d C a a n d SMg (R2 = 0.53, n = 26) ( T a b l e 6.31). T h i s r e s u l t s u g g e s t s t h a t y e l l o w s w e e t c l o v e r may b e f i x i n g N . U n f o r t u n a t e l y , a t h o r o u g h s e a r c h f o r n o d u l e s w a s n o t c o n d u c t e d a n d a n e g a t i v e c o r r e l a t i o n w i t h N w a s n o t a c h i e v e d w i t h t h e f u l l d a t a s e t s . O b s e r v a t i o n s o f e x t r e m e l y h i g h n e s t d e n s i t i e s i n y e l l o w s w e e t c l o v e r ( e . g . 11 n e s t s / i s l a n d a t S i s i b L a k e ( F i g u r e 3)) s u g g e s t t h a t t h i s s p e c i e s p r o v i d e s g o o d n e s t i n g c o v e r f o r s o m e d u c k s p e c i e s . I t s t o l e r a n c e f o r a w i d e r a n g e o f s o i l 128 c o n d i t i o n s , drought, and c o l d , i t s s o i l b u i l d i n g a b i l i t i e s , and the good n e s t i n g cover i t provides makes sweet c l o v e r a good choice f o r i s l a n d reclamation. Crested wheatgrass i s considered a drought t o l e r a n t species capable of t o l e r a t i n g adverse c o n d i t i o n s . On the study i s l a n d s , however, i t was one of the l e a s t frequent (Table 6.1) and had c o n s i s t e n t l y low coverage (Table 6.2). This r e s u l t was s u r p r i s i n g given i t s r e p u t a t i o n f o r t o l e r a n c e of poor growing c o n d i t i o n s . Crested wheatgrass i s commonly grown on a r i d rangelands and i s grazed h e a v i l y i n the s p r i n g because of i t s p e r s i s t e n c e . Because the i s l a n d s are o f t e n very dry, c r e s t e d wheatgrass was a n a t u r a l s e l e c t i o n . Unfortunately, aside from the moisture regime, i t appears t h a t the i s l a n d c o n d i t i o n s are not s u i t e d t o the p a r t i c u l a r adaptations of c r e s t e d wheatgrass. Crested wheatgrass i s moderately t o l e r a n t of a l k a l i n e c o n d i t i o n s (Watson et a l . 1980); however, t h i s species' cover was n e g a t i v e l y c o r r e l a t e d with pH (Table 6.21). The i s l a n d s w i t h the harshest c o n d i t i o n s tend t o be h i g h l y a l k a l i n e (pH > 8.0), sod i c , and compacted w i t h poor s t r u c t u r e , making any p l a n t growth d i f f i c u l t . Crested wheatgrass was obviously unsuited f o r these c o n d i t i o n s because i n 1985 and 1986, stepwise c o r r e l a t i o n i d e n t i f i e d BD and -pH c as the best r e l a t i o n s h i p (Table 6.21). Islands with a n e u t r a l r e a c t i o n u s u a l l y have b e t t e r s o i l s t r u c t u r e and more organic matter content, and, consequently, o f t e n have a more favourable moisture regime. 129 Although c r e s t e d wheatgrass i s considered a good competitor on dry rangelands, these n e u t r a l i s l a n d s (e.g. Louis and Bu t t e r Lakes) appear to be c o l o n i z e d q u i c k l y by p e r e n n i a l weeds, such as Canada t h i s t l e , or by seeded species adapted f o r more favourable c o n d i t i o n s , f o r example smooth brome grass and creeping red fescue. Crested wheatgrass adaptations make i t s u i t a b l e f o r dry, non-saline and n e u t r a l pH s o i l s , c o n d i t i o n s not found amongst the study i s l a n d s . Crested wheatgrass was prominent (15% i n 1985, and 4% i n 1986) on Waskwei Creek i s l a n d only — where the s o i l was n e u t r a l , non-sodic and had r e l a t i v e l y good crumb s t r u c t u r e . This i s l a n d was a l s o vegetated by seeded species p r i m a r i l y , which suggests t h a t g e n e r a l l y good seeding p r a c t i c e s were used and t h a t a good seedbed was prepared. On i s l a n d s i n southern A l b e r t a , dry s o i l c o n d i t i o n s and good s o i l s t r u c t u r e are more commonly found because the i s l a n d s are o f t e n b u i l t i n dry basins and t o p s o i l can be spread on the surface. Under these c o n d i t i o n , c r e s t e d wheatgrass does w e l l . T a l l wheatgrass, i n co n t r a s t to c r e s t e d wheatgrass, was the second most frequent species i n 1985 and the most frequent i n 1986 (Table 6.1). I t s mean f o l i a r cover ranked f i r s t i n 1986 and t h i r d i n 1985 (Table 6.2). T a l l wheatgrass was introduced from Russia where i t grows on s a l t f l a t s and seashores. Although i t i s not considered drought t o l e r a n t or e a s i l y e s t a b l i s h e d , i t i s considered to be the most s a l t t o l e r a n t c u l t i v a t e d species (Watson et a l . 1980) .. 130 This f e a t u r e makes i t u s e f u l f o r reclamation. L i k e many of the other species, t a l l wheatgrass cover i s r e l a t e d to pH w l e v e l s i n the s o i l (Table 6.29); however, u n l i k e most species , t a l l wheatgrass responds p o s i t i v e l y t o a l k a l i n e c o n d i t i o n s . T a l l wheatgrass, a bunch grass, tended to be the dominant species on the sodic i s l a n d s , such as R o l l y v i e w and Paulgaard Marshes. On these i s l a n d s i t grew i n l a r g e bunches, u s u a l l y about 25 to 35 cm i n diameter at the base and about 1 m t a l l . Between these bunches there was o f t e n bare ground (Figures 4 and 5) . In general, the bunches showed good vigour, s e t t i n g seed each year. On i s l a n d s with more moderate c o n d i t i o n s , t a l l wheat does not dominate, although on Waskwei Creek i s l a n d i t was frequent (92% i n 1985, and 75% i n 1986) and had r e l a t i v e l y high f o l i a r cover (9% i n 1985, and 3% i n 1986) . Vegetation on these i s l a n d s i s u s u a l l y more widespread so the i n t e r -bunch areas are b e t t e r vegetated than on the sodic i s l a n d s (e.g. Paulgaard and R o l l y v i e w Marshes). Intermediate wheatgrass was sown on three i s l a n d s (Kingston Slough, Louis Lake and Z i l k e Marsh) i n place of t a l l wheatgrass. I t was r e l a t i v e l y s u c c e s s f u l on Kingston Slough i s l a n d s , being q u i t e frequent (83% i n 1985, and 100% i n 198 6) and averaging 5% cover. In comparison, i t was u n s u c c e s s f u l at the other two s i t e s . Intermediate wheatgrass was not recorded on Louis Lake, and at Z i l k e Marsh i t was q u i t e frequent (80% i n 1985 and 20% i n 1986), but had minimal f o l i a r coverage (1% i n 1985 and 0% i n 1986). 131 In both appearance and response to s o i l c o n d i t i o n s , intermediate wheatgrass was s i m i l a r t o t a l l wheatgrass. Although considered a rhizomatous species, i t grew as a bunch grass on Kingston Slough i s l a n d s , almost i d e n t i c a l t o t h a t of t a l l wheatgrass. In a d d i t i o n , i t was best c o r r e l a t e d w i t h pH w, and, l i k e t a l l wheatgrass, i t responded p o s i t i v e l y ( r 2 = 0.30) to. a l k a l i n i t y (Table 6.23). A p o s i t i v e r e l a t i o n s h i p was a l s o i d e n t i f i e d between BD and t a l l and intermediate wheatgrass, and exchangeable Na and intermediate wheatgrass. These r e s u l t s are s u r p r i s i n g because intermediate wheatgrass i s not considered a s a l t or drought t o l e r a n t s p e c i e s , and t y p i c a l l y does not grow i n bunches (Watson et a l . 1980; Walton 1983) . P o s s i b l y , the bunch grass form i s a f u n c t i o n of the harsh growing c o n d i t i o n s , which prevented or g r e a t l y reduced rhizomatous spread, l e a v i n g d i s c r e t e and s c a t t e r e d bunches. Intermediate wheatgrass may a l s o be more t o l e r a n t of adverse c o n d i t i o n s than i s u s u a l l y assumed. Caution must be used i n drawing conclusions because i t was seeded at only three p r o j e c t s - one sodic and two r e l a t i v e l y moderate. Intermediate and t a l l wheatgrass d i d best under a l k a l i n e and sodic c o n d i t i o n s , u n l i k e a l l other seeded species and most nonseeded s p e c i e s . This q u a l i t y makes these species extremely v a l u a b l e f o r land reclamation and n e s t i n g v e g e t a t i o n under s a l i n e - a l k a l i n e c o n d i t i o n s . 132 On sodic i s l a n d s where these species predominate, l a r g e areas of bare s o i l are ofte n present. For example, Kingston Slough and Paulgaard Marsh i s l a n d s had > 65% bare s o i l coverage (Table 6.6). Means must be found t o f i l l these gaps q u i c k l y . S a l t meadow grass i s a common n a t i v e species of s a l i n e wetlands, where i t u s u a l l y i n h a b i t s s h o r e l i n e s . I t was recorded i n about one t h i r d of the quadrats, but u s u a l l y had f o l i a r cover values below 1%, probably because t h i s i s a f i n e - l e a v e d , r e l a t i v e l y small grass (Tables 6.1 and 6.2). Li k e t a l l and intermediate wheatgrass, s a l t meadow grass cover increased i n 1985 wit h i n c r e a s i n g l e v e l s of BD, a l k a l i n i t y and s o d i c i t y . Not s u r p r i s i n g l y then, i t was recorded on the 4 sodic i s l a n d s (Hebert Lake, Kingston Slough, and Paulgaard and R o l l y v i e w Marshes) w i t h r e l a t i v e l y good coverage (1 - 5%). S a l t meadow grass cover was best on Kingston Slough (Mean = 4%), where the s o i l i s s a l i n e (4.6 dS/m), sodic (SAR = 42.4) and a l k a l i n e (pH > 8.0). S i m i l a r l y , i t decreased w i t h i n c r e a s i n g l e v e l s of C (Table 6.25). Stepwise c o r r e l a t i o n a n a l y s i s i d e n t i f i e d pH c as the best determinant of s a l t meadow grass f o l i a r cover. In 1986, the only s i g n i f i c a n t r e l a t i o n s h i p was a negative c o r r e l a t i o n w i t h s o l u b l e Ca. S a l t meadow grass seldom grows i n dense or homogeneous stands s u i t a b l e f o r n e s t i n g cover; however, i t improves the seedbed and helps vegetation establishment on sodic i s l a n d s . I t s t o l e r a n c e of a l k a l i n e and high s a l t c o n d i t i o n s makes i t 133 an a t t r a c t i v e species f o r reclamation work. Although t h i s species has been seeded on e a r t h i s l a n d s , i t has not been observed to be s u c c e s s f u l . F o x t a i l barley i s commonly found on DU i s l a n d s (Figures 4 and 5) . Being adapted to s a l i n e c o n d i t i o n s and i n t e r m i t t e n t f l o o d i n g , i t o f t e n i n h a b i t s slough and i s l a n d s h o r e l i n e s , and s e a s o n a l l y flooded b a s i n s . Best et a l . (1978) de s c r i b e d f o x t a i l b a r l e y as a f a c u l t a t i v e halophyte adapted to a wide v a r i e t y of environmental c o n d i t i o n s . In 1985 and 1986 51% of the p l o t s contained f o x t a i l b a r l e y p l a n t s (Table 6.1). F o l i a r cover was near 5% i n both years, ranking seventh i n comparison to other species i n 1985 and f i f t h i n 1986 (Table 6.2). F o x t a i l b a r l e y i s not p r e f e r r e d n e s t i n g v e g e t a t i o n f o r waterfowl, d e s p i t e being a widespread and abundant s p e c i e s . One seldom f i n d s nests i n dense f o x t a i l b a r l e y stands, perhaps because i t grows i n areas where the p o s s i b i l i t y of f l o o d i n g e x i s t s . F o x t a i l b a r l e y serves a u s e f u l f u n c t i o n i n v e g e t a t i n g bare s h o r e l i n e and s a l t y areas. In a d d i t i o n , i t helps t o break up the surface l a y e r of s o i l , a l l o w i n g more d e s i r a b l e species to e s t a b l i s h . F o x t a i l b a r l e y does not p e r s i s t i n areas unless there i s f a i r l y r e g u l a r f l o o d i n g or disturbance, and w i l l decrease under competition from aggressive species b e t t e r adapted to s a l i n e or wet c o n d i t i o n s (Best et a l . 1978). Although f o x t a i l b a r l e y i s a l k a l i n e and s a l i n e t o l e r a n t and e s t a b l i s h e s r e a d i l y , i t s 134 value for reclamation is limited because of i t s status as a noxious weed. Foxtail barley tolerance for saline soils comes through in the correlation analysis (Table 6.22). It responded positively to increasing levels of exchangeable Mg, K and Na in 1985, and. to EC in both years. Further, in 1985 a combination of exchangeable Ca and Mg explained about 30% of i t s distribution on islands. In 1986, exchangeable and soluble Mg described about 40% of the pattern of cover data. As would be expected by a shoreline species, i t grew best on the lower areas of the islands. Smooth brome grass is a rhizomatous forage species commonly used because i t is tolerant of extreme temperatures and produces long-lived open swards (Walton 1983). A l l study islands had smooth brome grass sown on them and this species was recorded in 46% of the quadrats (Table 6.1). Despite a relatively high frequency, smooth brome grass f o l i a r cover was relatively, low, close to 2% each year and ranking eighth on Island No. 1 in 1985 and 1986 (Table 6.2). Smooth brome grass f o l i a r cover was negatively correlated to pH in both years. In 1985, alkalinity and BD were the major influences on f o l i a r cover, while in 1986 alkalinity (pHc), height-above-water and exchangeable -Ca were identified (Table 6.27). The influence alkalinity has on f o l i a r cover was discussed e a r l i e r . In general, exchangeable and soluble Ca have the opposite, beneficial effect, as evidenced by the positive effect i t had on total 135 f o l i a r cover (Table 6.14). Smooth brome grass, on the other hand, was s e n s i t i v e to high l e v e l s of exchangeable Mg, Na, and Ca, and EC, suggesting i t i s s e n s i t i v e to s a l i n e s o i l s (Table 6.27). These f i n d i n g s concur w i t h the g e n e r a l i z a t i o n s made i n a review by Watson et a l . (1980), which s t a t e d smooth brome grass can only t o l e r a t e m i l d a l k a l i n i t y and does not t o l e r a t e sodic c o n d i t i o n s . Smooth brome grass appears to p r e f e r dry s i t e s , f o r example i s l a n d tops, as f o l i a r cover improved as the i s l a n d top was approached. In a d d i t i o n , smooth brome grass grew best on the d r i e r , s o u t h - f a c i n g slopes, as the negative c o r r e l a t i o n w i t h aspect i n d i c a t e s . Smooth brome grass i s considered a drought r e s i s t a n t species (Watson et a l . 1980). Aspect was used as a c a t e g o r i c a l v a r i a b l e so conclusions based on i t must be made with c a u t i o n . Creeping red fescue i s a s m a l l , f i n e - l e a v e d grass. Because of i t s growth form and i t s a b i l i t y to form a dense t u r f , i t i s commonly used as a bottom grass or f o r e r o s i o n c o n t r o l (Walton 1983). Creeping red fescue was p l a n t e d on a l l i s l a n d s except Kingston Slough. Creeping red fescue frequency was s i m i l a r to smooth brome grass - about 45% (Table 6.1). Despite i t s small s i z e , creeping red fescue f o l i a r cover (41% i n 1985 and 46% i n 1986) ranked s i x t h on I s l a n d No. 1 i n both years (Table 6.1). On i s l a n d s , creeping red fescue tended t o grow as a bottom grass. Generally i t grew i n the shade of smooth 136 brome grass or forbs, with creeping red fescue seed heads and the longer leaves poking through canopy openings. Alkalinity (pHw and pHc) and sodicity (exchangeable Na) were detrimental to f o l i a r cover in 1985 and 1986 (Table 6.24). pHc was considered the best determinant of f o l i a r cover in 1986, while pHw and i n f i l t r a t i o n rate were best in 1985. Since i n f i l t r a t i o n rate was identified i t suggests that creeping red fescue may prefer soils with good structure. Strengthening this view, C was positively correlated with creeping red fescue in 1986. Foliar cover improved towards the island middle, or top. Although creeping red fescue i t s e l f may not provide good nesting cover, i t f i l l s in areas between bunch grasses and forbs and helps to stabilize the island s o i l s . On islands where grasses predominate, such as Waskwei Creek, creeping red fescue, along with other species, formed a sward that provided excellent nesting cover. Creeping red fescue is tolerant of a wide range of conditions, so long as there is ample moisture (Watson et a l . 1980). In fact Watson et a l . (1980) reported an observation of rhizosheaths in some populations growing on disturbed sites in Alberta. The rhizosheaths may be able to fix N and enable this species to colonize disturbed sites. The sedges, Carex atherodes and C. rostrata, were combined for the data analysis. This decision was made because they have similar l i f e histories and habitat requirements. 137 Sedge f o l i a r cover d e c l i n e d w i t h r i s i n g a l k a l i n i t y ( p H c & w ) i n both years, and a l k a l i n i t y (pH c) was i d e n t i f i e d by stepwise c o r r e l a t i o n . a n a l y s i s as the strongest subset. Awned sedge (Carex atherodes) can t o l e r a t e m i l d l y a l k a l i n e and s a l i n e c o n d i t i o n s . The t o l e r a n c e of beaked sedge (Carex rostrata) i s probably s i m i l a r because they are sympatric s p e c i e s . These sedges are s h o r e l i n e or shallow water s p e c i e s ; consequently i t was no s u r p r i s e t h a t height-above-water c o r r e l a t e d n e g a t i v e l y with f o l i a r cover (Table 6.26). These sedges were recorded i n 22% of the quadrats i n 1986 (Table 6.1), and i n terms of f o l i a r cover ranked n i n t h on I s l a n d No. 1 i n 1985 (2.2%) and 1986 (1.2%). I t i s apparent from these data t h a t sedges are not a dominant species on the i s l a n d s ; however, i s l a n d t r a n s e c t s s t a r t e d above the high water mark, thus e x c l u d i n g the best sedge h a b i t a t . Sedges o f t e n formed f a i r l y l u s h , dense stands on an i s l a n d ' s perimeter. These stands tend to form q u i c k l y a f t e r c o n s t r u c t i o n from rhizomes dredged up during c o n s t r u c t i o n , and by wind and water borne seeds. Awned sedge i s considered an aggressive species because of i t s rhizomatous h a b i t and p r o l i f i c growth. Beaked sedge i s probably q u i t e s i m i l a r . Sedge rhizomes were of t e n encountered on i s l a n d s while s o i l sampling, even on i s l a n d tops. The s h o r e l i n e sedge stands form a b a r r i e r against water e r o s i o n and may, on higher ground, provide a good seedbed f o r seeded s p e c i e s . Watson et a l . (1980) a l s o considers awned sedge to be a good 138 s o i l s t a b i l i z e r because o f i t s r h i z o m a t o u s growth and c o n t r i b u t i o n t o s o i l o r g a n i c m a t t e r . The bands o f v e g e t a t i o n r i n g i n g i s l a n d s a l s o p r o v i d e n e s t i n g c o v e r f o r ducks, such as l e s s e r scaup. Whitetop grass i s adapted t o s e a s o n a l l y f l o o d e d zones of s m a l l s l o u g h s o r th e s h a l l o w edges o f l a r g e r w a t e r b o d i e s ( N e c k l e s e t a l . 1985); c o n s e q u e n t l y on i s l a n d s i t i n h a b i t s s h o r e l i n e s and low ar e a s s u b j e c t t o f l o o d i n g . W h i t e t o p g r a s s i s s u c c e s s f u l on Houcher Lake i s l a n d s and t h e s u r r o u n d i n g marsh l a n d because i t f l o o d s r e g u l a r l y . I n t h e s p r i n g o f 1985, Houcher Lake i s l a n d s were under water f o r a s h o r t t i m e . W h i t e t o p g r a s s a c c o u n t e d f o r 22% and 40% o f t h e f o l i a r c o v e r f o r I s l a n d s 1 and 2 i n 1985, and 21% on I s l a n d 1 i n 198 6 (Appendix 3) . On Houcher F l a t i s l a n d s , w h i t e t o p g r a s s a v e r a g e d 6% c o v e r i n 1985. I n 1986, even though t h i s i s l a n d was h e a v i l y g r a z e d , w h i t e t o p g r a s s s t i l l a c c o u n t e d f o r 5% f o l i a r c o v e r . W h i t e t o p g r a s s was r e c o r d e d i n 34 and 20% o f q u a d r a t s i n 1985 and 1986, r e s p e c t i v e l y , and ra n k e d f i f t h i n f o l i a r c o v e r i n 1985 (3.5%) and s e v e n t h i n 1986 (2.5%), on I s l a n d No. 1. On I s l a n d No. 2 i n 1985 i t had t h e h i g h e s t mean f o l i a r c o v e r (8.6%) (Tables 6.1 and 6.2). W h i t e t o p g r a s s d i d p o o r l y on a l k a l i n e o r compacted s o i l s . I t was not r e c o r d e d on any o f t h e a l k a l i n e and compacted i s l a n d s , e x c e p t f o r P a u l g a a r d Marsh, where i t was found on I s l a n d 2 w i t h moderate f o l i a r c o v e r (3%) . I n 1985 and 1986, f o l i a r c o v e r improved w i t h i n c r e a s i n g l e v e l s o f 139 exchangeable Ca, Mg, and K, and EC. In 1986, exchangeable Na and satEC produced a s i m i l a r r e s u l t (Table 6.30). Neckles et a l . (1985) s t a t e d t h a t s a l i n i t y i s a major f a c t o r r e g u l a t i n g whitetop grass d i s t r i b u t i o n , and t h a t i t i s most abundant i n moderately s a l i n e (2.5-7.5 dS/m) h a b i t a t s . S i m i l a r t o other s h o r e l i n e species, whitetop grass cover d e c l i n e d towards the middle of the i s l a n d . Exchangeable Ca and Mg, and -height-above-water provided the strongest r e l a t i o n s h i p i n 1985, e x p l a i n i n g c l o s e to 40% of the species cover. In 1986, EC and exchangeable K e x p l a i n e d n e a r l y 60% of the v a r i a t i o n i n cover. Whitetop grass o f t e n forms homogeneous, r e l a t i v e l y dense swards, which provide good n e s t i n g cover and e r o s i o n p r o t e c t i o n f o r i s l a n d s . In shallow water areas, whitetop grass provides feeding and brood-rearing h a b i t a t f o r waterfowl. Canada t h i s t l e was the dominant nonseeded forb species found on the i s l a n d s , a f t e r s o w . t h i s t l e . Canada t h i s t l e was encountered i n about h a l f of the quadrats (48% i n 1985 and 52% i n 1986) (Table 6.1), and had good f o l i a r cover (Table 6.2). F o l i a r cover on I s l a n d No. 1 ranked f o u r t h o v e r a l l i n 1985 (4.7%) and second i n 1986 (9.1%), behind only t a l l wheatgrass. Canada t h i s t l e i s a noxious a g r i c u l t u r a l weed, c o l o n i z i n g and p e r s i s t i n g i n c u l t i v a t e d f i e l d s and d i s t u r b e d areas; consequently i t s success on these i s l a n d s i s not 140 s u r p r i s i n g (Figure 7) . The bare, moist and newly-cons t r u c t e d i s l a n d s are i d e a l f o r c o l o n i z i n g . The wetlands are o f t e n surrounded by c u l t i v a t e d lands supporting stands of t h i s species and provide a l a r g e seed source f o r i n v a d i n g new areas. A l k a l i n i t y (pH w) and high BD suppressed Canada t h i s t l e f o l i a r cover, and i t appears to be p a r t i c u l a r l y s e n s i t i v e to poor s o i l s t r u c t u r e (Table 6.20). This species was r a r e on the 4 a l k a l i n e , compacted i s l a n d s (Hebert Lake, Kingston Slough, Paulgaard and R o l l y v i e w Marshes) , being recorded i n one quadrat of each i s l a n d at the most (Appendix 3) . On these i s l a n d s i t s f o l i a r cover was 0%. Organic C and N, which are r e f l e c t i o n s of BD and s o i l s t r u c t u r e , had a p o s i t i v e i n f l u e n c e on t h i s t l e f o l i a r cover. Further, t o t a l and a e r a t i o n p o r o s i t y were s t r o n g l y c o r r e l a t e d w i t h f o l i a r cover. 141 Figure 7. Photograph of the dense, nonseeded v e g e t a t i o n on Louis Lake, August 1986. The v e g e t a t i o n has been removed from t h i s quadrat and provides a good view of the dense cover some nonseeded species provide. In t h i s photograph, Canada t h i s t l e , sow t h i s t l e , and mint are v i s i b l e . I n f i l t r a t i o n cans are a l s o v i s i b l e . The stepwise c o r r e l a t i o n r e s u l t s support the a s s e r t i o n that Canada t h i s t l e i s s e n s i t i v e to s o i l p h y s i c a l p r o p e r t i e s . In 1985, the combination of i n f i l t r a t i o n rate and C was i d e n t i f i e d , while i n 1986, a r e l a t i o n s h i p between Canada t h i s t l e and exchangeable Na and C was i d e n t i f i e d . Of course, i n f i l t r a t i o n r a t e r e f l e c t s pore volume and d i s t r i b u t i o n , and s o d i c i t y a f f e c t s both s o i l s t r u c t u r e and s o l u t i o n . These f i n d i n g s are supported by research 142 conducted elsewhere on Canada t h i s t l e . In general, Canada t h i s t l e i s found on open mesic areas. Well aerated, moist, unshaded environments produce good stands, whereas p o o r l y aerated or high water t a b l e s suppress growth (Moore 1975). Although Canada t h i s t l e was rare on the s o d i c - a l k a l i n e i s l a n d s ; i t e s t a b l i s h e d w e l l on i s l a n d s w i t h b e t t e r c o n d i t i o n s , o f t e n to the detriment of seeded s p e c i e s . Since these i s l a n d s had b e t t e r moisture and seedbed c o n d i t i o n s , one would expect seeded species to e s t a b l i s h r e a d i l y . I t appears, however, t h a t Canada t h i s t l e and other weedy species q u i c k l y invade, e s t a b l i s h , and out-compete seeded species f o r space, n u t r i e n t s , and water. F e r t i l i s i n g these i s l a n d s at seeding time probably enhances the weedy species because they can draw on the added n u t r i e n t s . There was only one other wetland, besides the 4 sodic wetlands, where Canada t h i s t l e was rare (recorded i n 0 or 1 quadrat) and had 0% f o l i a r cover — Waskwei Creek. Although the s o i l on t h i s i s l a n d s u i t a b l e f o r Canada t h i s t l e , i t seems th a t a w e l l e s t a b l i s h e d stand of domestic grasses (smooth brome grass, t a l l and c r e s t e d wheatgrasses, and creeping red fescue) prevented Canada t h i s t l e from e s t a b l i s h i n g and becoming predominant. Canada t h i s t l e d i sperses q u i c k l y and widely by wind and water. Once e s t a b l i s h e d at a s i t e , sexual reproduction and e s p e c i a l l y v e g e t a t i v e propagation w i t h creeping roots allows them to spread and p e r s i s t s u c c e s s f u l l y (Moore 1975). These q u a l i t i e s enable i t s success on e a r t h i s l a n d s . 143 Canada t h i s t l e i s considered a noxious weed by the F e d e r a l and most p r o v i n c i a l governments, so landowners or users are r e q u i r e d to c o n t r o l stands of t h i s t l e . These stands appear, however, to serve a u s e f u l purpose on i s l a n d s . F i r s t , t h i s species improves s o i l s t r u c t u r e through root and rhizome growth. I t a l s o provides quick s o i l cover t h a t minimizes s o i l e r o s i o n and i s l a n d d e t e r i o r a t i o n . F i n a l l y , rank, broad-leaved weeds, such as Canada t h i s t l e , provide good n e s t i n g cover (Hines and M i t c h e l l 1983) . A l l o w i n g the establishment of t h i s t l e stands on these grounds, however, i s probably not acceptable f o r p u b l i c r e l a t i o n and l e g a l reasons. I f these p l a n t s improve the seedbed and a l l o w seeded species t o e s t a b l i s h then Canada t h i s t l e may s t i l l be a u s e f u l f i r s t step i n . i s l a n d v e g e t a t i o n establishment. Because Canada t h i s t l e i s a p e r s i s t e n t p e r e n n i a l weed, some management a c t i o n , i n the form of mowing or spraying, would be r e q u i r e d . Sow t h i s t l e , l i k e Canada t h i s t l e , i s a p e r s i s t e n t , p e r e n n i a l weed with an extensive creeping root system. I t produces many seeds which disperse widely by wind and water and may l i e dormant i n the s o i l f o r many years (A l b e r t a A g r i c u l t u r e 1983) . Sow t h i s t l e was one of the most s u c c e s s f u l species on the i s l a n d s (Figure 7) . I t was the most frequent (70%) species i n 1985 and the second most (54%) i n 1986 (Table 6.1). I t s f o l i a r cover ranked second i n 1985 (6.8%) and t h i r d i n 1986 (7.7%) on I s l a n d No. 1 and f i f t h on I s l a n d No. 2 i n 1985 (4.6%) (Table 6.2). 144 Sow t h i s t l e d i d p o o r l y under a l k a l i n e , sodic and compacted c o n d i t i o n s , c o n d i t i o n s t h a t p r e v a i l e d during the drought of 1985 (Table 6.28). In 1986, w i t h b e t t e r r a i n f a l l , i t seemed to be a f f e c t e d only by s a l i n e and sodic c o n d i t i o n s . Sow t h i s t l e was s i m i l a r to Canada t h i s t l e not only i n i t s response to a l k a l i n i t y , s o d i c i t y and BD, but a l s o i n i t s s i g n i f i c a n t p o s i t i v e response to N and C (Tables 6.20 and 6.28). Both these species appear to p r e f e r the mesic i s l a n d s w i t h good s o i l s . F e r t i l i s i n g mesic i s l a n d s may only serve to enhance weed establishment, s i n c e both sow t h i s t l e and Canada t h i s t l e responded p o s i t i v e l y t o t o t a l N l e v e l s . With t h e i r numerous seeds these species can di s p e r s e widely, invade and e s t a b l i s h q u i c k l y and prevent more d e s i r a b l e species, seeded and nonseeded, from e s t a b l i s h i n g . F. WEATHER EFFECTS ON FOLIAR COVER None of the weather v a r i a b l e s r e l a t e d t o p r e c i p i t a t i o n or growing degree days (GDD) had a measurable i n f l u e n c e on f o l i a r cover. S i t e - s p e c i f i c measurements were not a v a i l a b l e f o r any of the i s l a n d s so weather summaries from nearby m e t e o r o l o g i c a l s t a t i o n s were used. Although there i s no doubt t h a t weather has a strong i n f l u e n c e on p l a n t growth, and, consequently, f o l i a r cover, i t i s u n l i k e l y t h a t the r e s o l u t i o n of weather and ve g e t a t i o n data was s u f f i c i e n t to detect c o r r e l a t i o n s . 145 Large d i f f e r e n c e s i n t o t a l monthly r a i n f a l l p a t t e r n s occurred between 1985 and 1986. Nineteen e i g h t y - f i v e was a drought year as the summer (May to July) r a i n f a l l at the Camrose m e t e o r o l o g i c a l s t a t i o n was only 51% of the 30year normal. In c o n t r a s t , the 1986 f i g u r e was 25% higher than normal. In the western p a r t of the study area, Camrose and S t e t t l e r N m e t e o r o l o g i c a l s t a t i o n s , the t o t a l r a i n f a l l f o r May t o J u l y increased 145% and 123%, r e s p e c t i v e l y from 1985 to 1986. In the eastern p a r t of the study area (Coronation A s t a t i o n ) , r a i n f a l l i ncreased 174%. The vast m a j o r i t y of the in c r e a s e d r a i n f a l l came during J u l y , which i n c r e a s e d by 520, 626 and 291% at the Camrose, Coronation A and S t e t t l e r N weather s t a t i o n s , r e s p e c t i v e l y . June r a i n f a l l i n c r e a s e d s l i g h t l y (Table 4.3). Despite l a r g e r a i n f a l l i n c r e a s e s , o v e r a l l t o t a l f o l i a r cover and nestingboard cover on I s l a n d Nos. 1 d i d not change ap p r e c i a b l y from 1985 to 1986 (50.5 & 51.7% mean t o t a l f o l i a r cover, and 48.9 & 49.5% nestingboard cover, r e s p e c t i v e l y ) (Table 6.4). On a p r o j e c t b a s i s , 7 of 11 p r o j e c t s (Reta P r o j e c t was not sampled i n 1986) showed an incr e a s e , but i n 3 of the 7 cases the increase was under 3 percentage p o i n t s . The J u l y , 198 6 r a i n s were probably too l a t e i n the year to s i g n i f i c a n t l y improve f o l i a r cover, because much of the ve g e t a t i v e growth i s complete by e a r l y J u l y . In t h i s study, f o l i a r cover was measured i n l a t e J u l y and e a r l y August. 146 Although the r a i n f a l l d i d not seem to d i r e c t l y a f f e c t p l a n t cover, the 1985 r a i n f a l l may have i n f l u e n c e d the v a r i a b l e s s i g n i f i c a n t l y c o r r e l a t e d w i t h cover i n 1986. For example, i n 1985 yellow sweet c l o v e r was n e g a t i v e l y c o r r e l a t e d w i t h BD, pH and Na, while i n 198 6 none of these v a r i a b l e s were important (Table 6.31). I t s p o s s i b l e t h i s response i s a t t r i b u t a b l e to yellow sweet c l o v e r ' s b i e n n i a l l i f e h i s t o r y , as the d i f f e r e n t stages may have d i f f e r e n t requirements. The r a i n f a l l may a l s o have ameliorated the s o i l c o n d i t i o n s by f l u s h i n g out some of the s o l u b l e s a l t s , although t h i s i s not supported by the data, or the a d d i t i o n a l moisture may j u s t have enabled the p l a n t s to overcome the chemical problems, such as osmotic s t r e s s . F i n a l l y , the d i f f e r e n c e s i n s e l e c t e d v a r i a b l e s between years may be a t t r i b u t a b l e s o l e l y to the n a t u r a l annual v a r i a t i o n i n p l a n t growth. F o x t a i l b a r l e y , s a l t meadow grass, sow t h i s t l e and, to a l e s s e r degree, smooth brome grass and whitetop grass show a s i m i l a r p a t t e r n between years to t h a t of sweet c l o v e r — t h a t i s , fewer c o r r e l a t i v e v a r i a b l e s i n 1986 (Tables 6.22, 6.25, 6.27, 6.28 and 6.30). G . DISCUSSION OF METHODS Two methods were used to measure v e g e t a t i v e cover on i s l a n d s : 1) the p o i n t - i n t e r c e p t and 2) nestingboard methods. Although both methods provide measures of cover, the p o i n t - i n t e r c e p t method can provide data on t o t a l and species f o l i a r cover, b a s a l cover and frequency. The 147 nestingboard can be used only f o r t o t a l f o l i a r cover, but i t i s a r a p i d survey technique. I f only t o t a l cover i s re q u i r e d , t h i s method may be appr o p r i a t e . The p o i n t -i n t e r c e p t method can a l s o be q u i t e f a s t i f p l a n t h i t s are not i d e n t i f i e d to species. This method, however, i s s t i l l slower than the nestingboard because the i n d i v i d u a l p i n -drops must be observed and recorded i n d i v i d u a l l y . Nestingboard and p o i n t - i n t e r c e p t f o l i a r cover was s t r o n g l y c o r r e l a t e d (p. 118). They were c o r r e l a t e d with almost e x a c t l y the same s o i l and s i t e v a r i a b l e s (Table 6.14 and 6.15), so f o r r a p i d s o i l and ve g e t a t i o n reconnaissance a nestingboard would be adequate (pp. 118 - 120). P h y s i c a l s o i l analyses i n c l u d e d measurements of bulk d e n s i t y , p o r o s i t y and i n f i l t r a t i o n . Most p h y s i c a l analyses are time-consuming and c o s t l y i n comparison w i t h chemical analyses. P h y s i c a l analyses have not been used as widely because of the cost and problems a s s o c i a t e d with r e p r o d u c i b i l i t y and s t a n d a r d i z a t i o n of methods (Sims et a l . 1984); consequently a l a r g e body of l i t e r a t u r e r e l a t i n g p l a n t p r o d u c t i v i t y parameters to p h y s i c a l s o i l c o n d i t i o n s has not been developed. In t h i s study, BD was a very important ' p r e d i c t o r v a r i a b l e f o r f o l i a r cover. Although the excavation method was time consuming, i t provided v a l i d , c o n s i s t e n t data. Pore d i s t r i b u t i o n was measured on only 21 s o i l cores. Although the sample i s s m a l l , i t was c o r r e l a t e d w i t h many species and t o t a l f o l i a r cover. A l a r g e r sample of a e r a t i o n 148 p o r o s i t y data would be worthwhile o b t a i n i n g , u n f o r t u n a t e l y , f o r management purposes, t h i s method i s too c o s t l y and time-consuming to use on a l a r g e s c a l e . Bulk d e n s i t y can be measured r e l a t i v e l y q u i c k l y , but compared to chemical analyses i t too i s time-consuming. Measuring i n f i l t r a t i o n r a t e s w i t h s i n g l e - r i n g i n f i l -trometers produced h i g h l y v a r i a b l e data, i n 1985 e s p e c i a l l y . E s t a b l i s h i n g steady-state i n f i l t r a t i o n was d i f f i c u l t i n 1985 because of the dry s o i l c o n d i t i o n s . H o r i z o n t a l flow was d i f f i c u l t t o c o n t r o l under these c o n d i t i o n s . In 1986, heavy r a i n f a l l i n J u l y maintained near s a t u r a t e d c o n d i t i o n s much of the time, and l a r g e underground cracks or holes were avoided. The r e d u c t i o n i n o v e r a l l mean i n f i l t r a t i o n rates, from 64.8 cm/h i n 1985 t o 13.0 cm/h i n 1986 r e f l e c t s the change i n i n f i l t r o m e t e r placement and the moister s o i l c o n d i t i o n s (Table 6.13) . The v a l i d i t y of a v o i d i n g cracks when p l a c i n g cans can be debated, but g e n e r a l l y these s i t u a t i o n s developed c l o s e to the s h o r e l i n e where muskrats were burrowing or the i s l a n d eroding and slumping. I t was decided these c o n d i t i o n s r e f l e c t e d only a short-term s i t u a t i o n , as the s o i l would soon slump and erode away; consequently s i t e s t y p i c a l of i s l a n d s i n good shape were chosen. Chemical analyses conducted on the i s l a n d s o i l s were standard t e s t s used i n a g r i c u l t u r a l research. Most of these analyses can be run r e l a t i v e l y cheaply on l a r g e numbers of samples. For example, pH can be done cheaply, and yet was 149 one of the most important p r e d i c t o r v a r i a b l e s . E l e c t r i c a l c o n d u c t i v i t y i s another example. Both exchangeable and s o l u b l e Ca, Mg, and Na are important analyses to conduct. Potassium i s r a r e l y d e f i c i e n t i n A l b e r t a . Soluble c a t i o n l e v e l s i n d i c a t e the q u a n t i t y of s a l t i n the s o i l s o l u t i o n and can be used to c a l c u l a t e the SAR. Although SAR could only be c a l c u l a t e d on 26 samples i n 1986, i t was an important p r e d i c t o r v a r i a b l e f o r t o t a l f o l i a r and nesting-board cover. Exchangeable c a t i o n measurements provide an estimate of the c a t i o n s on the exchange complex, thus they provide an i n d i r e c t measure of p o t e n t i a l s o d i c i t y and s a l i n i t y . Organic C and N were both measured on i s l a n d s s o i l s . Organic C was analysed u s i n g the Walkley-Black method (McKeague 1978) because i t measures only the organic C p o r t i o n , e x c l u d i n g CaC03 and carbonized m a t e r i a l (e.g. c o a l ) . T o t a l N, analyzed because i t i s l e s s v a r i a b l e than other forms of N, was found to c o r r e l a t e almost p e r f e c t l y ( r 2 = 0.99, See p. 95) w i t h C i n both years. Obviously only one measurement would be necessary i n subsequent years. Organic C would be a good choice f o r management purposes because most managers have an i n t u i t i v e understanding of t h i s v a r i a b l e . Carbon (%) i s u s u a l l y m u l t i p l i e d by 1.724 to convert i t to percent organic matter. Several c a t e g o r i c a l v a r i a b l e s were used i n the study but, being c a t e g o r i c a l , they could not be used i n the 150 c o r r e l a t i o n a n a l y s i s . These v a r i a b l e s , macrotopography and effervescence, served to the c o r r e l a t i o n r e s u l t s . H. SOIL VARIABILITY S o i l s are heterogenous bodies t h a t vary s p a t i a l l y and temporally. S p a t i a l l y , s o i l s vary h o r i z o n t a l l y and v e r t i c a l l y . S o i l v a r i a b i l i t y can be so great t h a t i t i s not f e a s i b l e to estimate d i f f e r e n c e s among the u n i t s w i t h any degree of accuracy (Petersen and C a l v i n 1965). This study was designed to e s t a b l i s h r e l a t i o n s h i p s between environmental p r o p e r t i e s and f o l i a r cover; consequently, c o r r e l a t i o n a n a l y s i s was employed and i s l a n d estimates of the p r o p e r t i e s were not needed. Comparisons between i s l a n d s and between years were not made p r i m a r i l y because the r e l a t i o n s h i p s between s o i l s and ve g e t a t i o n were of i n t e r e s t ; however, the l a r g e sample s i z e s r e q u i r e d a l s o precluded such an a n a l y s i s . To o b t a i n a s o i l estimate f o r a l l the i s l a n d s , between 60 and 4 500 samples are re q u i r e d , depending on the property of i n t e r e s t . For example, t o obta i n an o v e r a l l p o p u l a t i o n estimate w i t h i n 10% of the mean and with 95% confidence r e q u i r e s about 600 samples f o r t o t a l N (638 and 652 i n 1985 and 1986), 150 samples f o r EC (140 and 173 i n 1985 and 1986), 60 samples f o r BD (58 and 62 i n 1985 and 1986), 300 f o r exchangeable Na (178 and 313 i n 1985 and 1986), and about 4 000 f o r i n f i l t r a t i o n (4 481 and 2 550 i n 1985 and 1986) . f o r example, help e x p l a i n 151 Sample s i z e s f o r po p u l a t i o n estimates from i n d i v i d u a l i s l a n d s vary considerably a l s o . For most s o i l p r o p e r t i e s , between 20 and 100 samples would be r e q u i r e d to ob t a i n a s u i t a b l e i s l a n d estimate. For example, exchangeable Na re q u i r e s 76 samples at Waskwei Creek, but only 14 are needed at Kingston Slough. S o i l v a r i a b i l i t y i s a f a c t o r t h a t must commonly be d e a l t w i t h i n f i e l d s t u d i e s . S l a v i n s k i (1977) found t h a t to c h a r a c t e r i z e most s o i l p r o p e r t i e s i n a B r i t i s h Columbia c o a s t a l f o r e s t p l o t he needed 20 to 90 samples. These p l o t s were 0.4 ha i n area. In a f o r e s t p l a n t a t i o n i n New York, s o i l v a r i a b i l i t y was gre a t e s t w i t h i n 1 m of i n d i v i d u a l t r e e bases (Riha et a l . 1986). This area was more v a r i a b l e than the v a r i a b i l i t y between stands of d i f f e r e n t t r e e s p e c i e s . I s l a n d s o i l v a r i a b i l i t y i s p r i m a r i l y the r e s u l t of the c o n s t r u c t i o n method. Islands are const r u c t e d by dredging bottom sediment i n t o a p i l e and then shaping i t w i t h the backhoe's bucket. Since dredging i s n o n - s e l e c t i v e , the i s l a n d i s composed of organic m a t e r i a l s found i n the wetland and the d i f f e r e n t sediment l a y e r s t h a t form the wetland bottom. The patchiness of the i s l a n d surface v a r i e s from wetland . to wetland, depending upon the s k i l l of the equipment operator and the composition of the wetland bottom. In 1986, BD on Waskwei Creek ranged from 477 kg/m3 t o 1413 kg/m3, a d i f f e r e n c e of almost 200%. D i f f e r e n c e s of t h i s magnitude were r e l a t i v e l y common and e x p l a i n s why the lar g e sample s i z e s are r e q u i r e d . 152 Some s o i l properties showed large differences between years. For example, mean BD at Butter Lake was 838 kg/m3 i n 1985 and 1460 kg/m3 i n 1986 (Table 6.11). Mean annual pHw increased from 7.4 i n 1985 to 8.1 i n 1986 (Table 6.10). The biggest change occurred with steady-state i n f i l t r a t i o n . Mean annual i n f i l t r a t i o n was 64.8 cm/h i n 1985, but dropped to 13.0 cm/h i n 1986. These differences are probably the re s u l t of two factors: 1) natural s o i l v a r i a t i o n on the islands and 2) sampling and a n a l y t i c a l differences between years. The former f a c t o r , s o i l heterogeneity, was discussed above i n r e l a t i o n to i s l a n d s o i l s . The l a t t e r point i s relevant to both f i e l d and laboratory techniques. For example, pH meters are sensitive to s o i l p a r t i c l e s i n solution; consequently, s o i l pH readings involve some s u b j e c t i v i t y and can vary between pH meters. The v a r i a b i l i t y of s o i l i n f i l t r a t i o n readings was mentioned i n the discussion of methods (p. 14 9) . The large v a r i a b i l i t y i n i n f i l t r a t i o n rates within and between years was a consequence of in f i l t r o m e t e r placement. In 1985, Island No. 1 means ranged from < 0.1 cm/h to 130.0 cm/h, whereas i n 1986 a l l values were < 65 cm/h. More consistent placement i n 1986, reduced the v a r i a b i l i t y . In 1986 cracks were avoided, and a greater e f f o r t to achieve saturated s o i l conditions was made. At Houcher F l a t , mean i n f i l t r a t i o n dropped from 127.2 cm/h i n 1985 to 25.8 cm/h i n 1986 (Table 6.13) . 153 8. SUMMARY OF RESULTS 1. Vegetation - s o i l r e l a t i o n s h i p s were i n v e s t i g a t e d on 20 man-made ea r t h i s l a n d s b u i l t by Ducks U n l i m i t e d Canada f o r waterfowl n e s t i n g cover. 2. In 1985, 59 v a s c u l a r p l a n t species were recorded; 40 species were recorded i n 1986. 3. Sow t h i s t l e and t a l l wheatgrass were the most frequent species i n 1985 and 1986, r e s p e c t i v e l y . Yellow sweet c l o v e r and t a l l wheatgrass had the gre a t e s t mean f o l i a r cover i n those years. 4. T a l l wheatgrass and yellow sweet c l o v e r were the most s u c c e s s f u l seeded species, i n terms of f o l i a r cover and frequency. Sow t h i s t l e , Canada t h i s t l e and f o x t a i l • b a r l e y were the most s u c c e s s f u l nonseeded spec i e s . 5. I s l a n d f o l i a r cover was approximately 50% i n 1985 and . 1986. In 1985 f o l i a r cover ranged from 14% on Kingston Slough t o 89% i n Louis Lake. In 1986, i t ranged from 16% on R o l l y v i e w Marsh to 84% at Louis Lake. 6. Seeded and nonseeded coverage averaged approximately 20% and 30%, r e s p e c t i v e l y , i n 1985 and 1986. On Ro l l y v i e w Marsh I s l a n d No. 1, bare s o i l comprised 77% of the i s l a n d cover, whereas bare s o i l was only 1% of the cover at Butte r Lake, Houcher Lake, Louis Lake and Waskwei Creek. 7. E l e c t r i c a l c o n d u c t i v i t y (1:2 s o i l : w a t e r ) of the i s l a n d s o i l s averaged 2.5 dS/m and 2.4 dS/m i n 1985 and 1986, . r e s p e c t i v e l y . 154 8. Exchangeable Ca averaged 1.1.2 cmol/kg i n 1985 and 12.7 cmol/kg i n 1986. Mean exchangeable Mg was 3.4 cmol/kg i n 1985 and 3.8 cmol/kg i n 1986. 9. Exchangeable Na averaged 5.9 cmol/kg i n 1985 and 6.4 cmol/kg i n 1986. SAR averaged 12.9 and ESP 19.0% i n 1986 10. S o i l pH (measured i n water) averaged 7.4 and 8.1 i n 1985 and 1986. Organic carbon averaged 3.0% and 3.4% i n 1985 and 1986. T o t a l N averaged 0.24% and 0.29% i n those years. 11. Bulk d e n s i t y averaged 1045 kg/m3 and 1138 kg/m3 i n 1985 and 1986. T o t a l p o r o s i t y averaged 59.2% and a e r a t i o n p o r o s i t y averaged 11.1% i n 1986. Steady-state i n f i l t r a t i o n averaged 64.8 cm/h and 13.0 cm/h i n 1985 and 1986. 12. Most quadrats faced northwest or east on slopes averaging about 4°. They tended to be l o c a t e d i n the upper slope. Quadrat height averaged 0.66 and 0.52 m above the high water l i n e i n 1985 and 1986. 13. No a v a i l a b l e weather v a r i a b l e s were c o r r e l a t e d (P > 0.05) with i s l a n d f o l i a r cover, nor were i s l a n d age and the time-since-seeding c o r r e l a t e d w i t h any measure of f o l i a r cover. 14. Seven v a r i a b l e s (-BD, exchangeable -Na, -pH, organic C, t o t a l N, and exchangeable Ca and Mg) were c o r r e l a t e d w i t h t o t a l f o l i a r cover i n 1985 and 1986. Stepwise m u l t i p l e c o r r e l a t i o n i d e n t i f i e d the r e l a t i o n s h i p 155 between f o l i a r cover and -pHw, exchangeable -Na and -BD as the best i n 1985 (R 2 = 0.64, n = 78). The best (R 2 = 0.56, n = 80) r e l a t i o n s h i p i n 1986 was wi t h EC, -BD, exchangeable -Na, and -pH. 15. Nestingboard cover was c o r r e l a t e d w i t h 5 v a r i a b l e s i n both 1985 and 1986: -BD, exchangeable -Na, exchangeable Ca, organic C, and t o t a l N. pH (-) was c o r r e l a t e d i n 1985 only, whereas Mg was c o r r e l a t e d i n 1986 only. The best (R 2 =0.42, n = 78) r e l a t i o n s h i p i d e n t i f i e d i n 1985 by m u l t i p l e c o r r e l a t i o n was -BD, -Na, and i n f i l t r a t i o n . In 1986 the best (R 2 = 0.50, 'n = 80) r e l a t i o n s h i p was with -height-above-water, EC, - i n f i l t r a t i o n , -pH, and -Na. 16. A l k a l i n i t y , s o d i c i t y , and BD exerted a strong i n f l u e n c e on t o t a l f o l i a r cover. This i n f l u e n c e i s a l s o apparent on the i n d i v i d u a l species. Over h a l f of the species analyzed were e i t h e r p o s i t i v e l y or n e g a t i v e l y c o r r e l a t e d with pH i n 1985 and 1986. S i m i l a r l y , about 30% of the species were c o r r e l a t e d w i t h BD and exchangeable Na. Most species were n e g a t i v e l y c o r r e l a t e d with these two v a r i a b l e s . Exchangeable Ca and EC were next i n importance at i n f l u e n c i n g f o l i a r cover. 156 9. CONCLUSIONS AND MANAGEMENT RECOMMENDATIONS Vegetation responds to a complex v a r i e t y of environmental v a r i a b l e s . On man-made e a r t h i s l a n d s a complex r e l a t i o n s h i p between f o l i a r cover and s o i l and s i t e c o n d i t i o n s i s evident; consequently, N u l l Hypothesis No. 1 was r e j e c t e d — i s l a n d f o l i a r cover i s r e l a t e d t o s o i l and s i t e c o n d i t i o n s . The c o r r e l a t i o n a n a l y s i s i n d i c a t e s t h a t three s o i l v a r i a b l e s have an o v e r - r i d i n g i n f l u e n c e : a l k a l i n i t y , s o d i c i t y and bulk d e n s i t y . Although other v a r i a b l e s p l a y important r o l e s through t h e i r a f f e c t on i n d i v i d u a l species and d i f f e r e n t measures of f o l i a r cover, the three p r o p e r t i e s i d e n t i f i e d above predominate. Seeded species, t a l l wheatgrass and yellow sweet c l o v e r i n p a r t i c u l a r , were important c o n s t i t u e n t s of i s l a n d v e g e t a t i o n ; however, nonseeded species provided more than h a l f (60%) of the f o l i a r cover. The nonseeded ve g e t a t i o n component was r i c h i n species, and s e v e r a l of them, f o r example Canada t h i s t l e , sow t h i s t l e and f o x t a i l b a r l e y , were frequent w i t h high f o l i a r cover. Unfortunately, many of the su c c e s s f u l nonseeded species are al s o considered noxious weeds, which, f o r a g r i c u l t u r a l reasons, l i m i t s t h e i r u s e f u l -ness. The f o l i a r cover of the nonseeded species, s e p a r a t e l y and together, responded p r i m a r i l y to the s o i l v a r i a b l e s l i s t e d above.. As a consequence, N u l l Hypothesis No. 2 was r e j e c t e d — nonseeded species f o l i a r cover i s r e l a t e d to s o i l and s i t e c o n d i t i o n s . 157 In general, the poo r l y vegetated i s l a n d s have high or extreme l e v e l s of two or three of the three predominant f a c t o r s . Most i s l a n d s w i t h high pH are a l s o h i g h l y sodic and have a high BD, but not a l l of the i s l a n d s w i t h high BD are sodic or s a l i n e . The s t u d y - i s l a n d s o i l s f i t a continuum ranging from n e u t r a l pH, low s a l t and good s t r u c t u r e t o h i g h l y s o d i c , a l k a l i n e and compacted. The a r i d environment i n which many of the i s l a n d s are constructed aggravates the already harsh growing c o n d i t i o n s . Although i s l a n d c o n d i t i o n s are harsh, n a t u r a l veg-e t a t i o n can t h r i v e under s i m i l a r c o n d i t i o n s . Reclaiming severe environments, such as the i s l a n d s , r e q u i r e s r e c o g n i t i o n of not only the adverse growing c o n d i t i o n s , but a l s o the costs and e f f o r t r e q u i r e d to ameliorate, these c o n d i t i o n s . The major problem w i l d l i f e managers face i s the i n i t i a l establishment of vegetation on the i s l a n d s . Seedlings are' more s e n s i t i v e to both p h y s i c a l and chemical s o i l c o n d i t i o n s , t h e r e f o r e the management e f f o r t must be made at the seeding stage. Before making management recommendations i t i s important to i d e n t i f y the o b j e c t i v e s of the i s l a n d seeding, or reclamation, p r o j e c t . F i r s t , the i s l a n d s should be vegetated as q u i c k l y as p o s s i b l e (< 3 years) to minimize e r o s i o n and maximize waterfowl p r o d u c t i v i t y and i s l a n d l o n g e v i t y . Secondly, the vegetation should be composed p r i m a r i l y of d e s i r a b l e species. " D e s i r a b l e " excludes noxious weeds, such as Canada t h i s t l e , and species which 158 provide poor n e s t i n g cover, such as f o x t a i l b a r l e y . With these o b j e c t i v e s i n mind, management recommendations can be made tha t w i l l enable the o b j e c t i v e s to be reached. Revegetation e f f o r t s must address the environmental c o n s t r a i n t s when fo r m u l a t i n g appropriate recommendations f o r 1) seedbed p r e p a r a t i o n , 2) seeding techniques and t i m i n g , and 3) species s e l e c t i o n . Seedbed p r e p a r a t i o n r e q u i r e s t h a t the s o i l c o n d i t i o n s be known beforehand. Although three s o i l problems ( s o d i c i t y , a l k a l i n i t y , and BD) were i d e n t i f i e d , only BD can be e a s i l y d e a l t w i t h on i s l a n d s . High Na and pH can be reduced by l e a c h i n g the s o i l w ith water and Ca and Mg s a l t s . ' With t h i s method, d i v a l e n t c a t i o n s replace Na on the exchange complex and the Na s a l t s are washed out. F a i l i n g to replace the Na w i t h a d i v a l e n t c a t i o n before i r r i g a t i n g allows the s o i l aggregates to d e f l o c c u l a t e and d i s p e r s e , c r e a t i n g an impervious s o i l s t r u c t u r e . On i s l a n d s t h i s approach may not be a f e a s i b l e a l t e r n a t i v e because of the cost, l o g i s t i c s , and l a c k of a s u i t a b l e water supply. Gypsum (CaSO^, however, i s a r e l a t i v e l y inexpensive s a l t t h a t i s o f t e n used f o r t r e a t i n g sodic s o i l s . Working gypsum i n t o the i s l a n d s o i l s at seeding time might ameliorate the sodic c o n d i t i o n s s u f f i c i e n t l y to a l l o w v e g e t a t i o n t o e s t a b l i s h . Except where the s o i l s are non-sodic and the water non-saline, i r r i g a t i o n i s not a f e a s i b l e a l t e r n a t i v e . To enhance n a t u r a l l e a c h i n g , i s l a n d s could be b u i l t with more freeboard (so that the 159 water t a b l e i s lower i n the i s l a n d ) ; however, t h i s i n v o l v e s g r e a t e r expense and i t may be l e s s a t t r a c t i v e to waterfowl. Although reducing s o d i c i t y and a l k a l i n i t y d i r e c t l y i s d i f f i c u l t , they can be ameliorated while addressing the problem of compaction (high BD). In f a c t , a l l three p r o p e r t i e s are so c l o s e l y r e l a t e d t h a t i t i s almost impossible t o i n f l u e n c e one without i n f l u e n c i n g the others somewhat. Because the l o g i s t i c s of i s l a n d work o f t e n preclude many management options, such as i r r i g a t i o n and t o p s o i l i n g , seedbed p r e p a r a t i o n of i s l a n d s w i t h high BD only i s s i m i l a r to those w i t h high BD and high Na and pH, except that gypsum i s not r e q u i r e d . To e s t a b l i s h v e g e t a t i o n s u c c e s s f u l l y a s u i t a b l e seedbed must be prepared. I t should have an open, granular s t r u c t u r e t h a t permits adequate i n f i l t r a t i o n , a e r a t i o n and root growth p e n e t r a t i o n . I s l a n d s o i l s with high BD, Na and pH tend to be compacted, cloddy and o f t e n w i t h a surface c r u s t . None of these c o n d i t i o n s are acceptable f o r s e e d l i n g establishment. Because l e a c h i n g the excess Na i s not f e a s i b l e , the seedbed can only be p h y s i c a l l y manipulated. I d e a l l y , t o p s o i l should be spread over an i s l a n d ' s surface and then seeded. The t o p s o i l may e v e n t u a l l y be a f f e c t e d by the u n d e r l y i n g s a l t - a f f e c t e d s o i l , but i t gives the v e g e t a t i o n a chance to e s t a b l i s h . DU has used t h i s approach q u i t e s u c c e s s f u l l y f o r i s l a n d s b u i l t i n a dry b a s i n , where they 160 can save the t o p s o i l for subsequent placement on the i s l a n d surface. Unfortunately, the cost and l o g i s t i c s involved i n doing t h i s for established wetlands are p r o h i b i t i v e , unless a t o p s o i l source i s available for winter a p p l i c a t i o n . Mulching the i s l a n d surface with manure or some other organic material i s an alte r n a t i v e to t o p s o i l a d d i t ion. Mulching opens the s o i l , conserves moisture, minimizes wind and water erosion, improves i n f i l t r a t i o n , prevents s o i l physical damage and provides nutrients. Manure i s the most l i k e l y mulch. It can be hauled from, a l o c a l source during the winter, and l a t e r spread and incorporated with a r o t o t i l l e r . Manuring, and mulching i n general, provides long-term b e n e f i t s , so one application should be s u f f i c i e n t . Plants w i l l benefit from the slow release of nutrients from organic mulches. The addition of organic matter to sodic s o i l s helps of f s e t s t r u c t u r a l damage caused by Na, by promoting aggregation. Disadvantages of mulching include the cost and l o g i s t i c problems associated with i s l a n d work. Mulching blankets can provide a f a s t e r , less labour intensive a l t e r n a t i v e to mulching, and s t i l l help i n erosion control and vegetation establishment on DU i s l a n d s . These blankets consist of mats of straw, or other organic or synthetic f i b r e , held i n place by ne t t i n g . Mulching blankets can also contain seed and f e r t i l i s e r . Mulching blankets should be considered for i s l a n d shores and for sodic and compacted s o i l s . 161 Some i s l a n d s o i l s have low BD, good organic matter l e v e l s and r e l a t i v e l y good s t r u c t u r e . These s o i l s , of course, r e q u i r e no mulching, although r o t o t i l l i n g the i s l a n d surface before seeding would be b e n e f i c i a l . P l a n t growth a l s o improves the seedbed, because roots penetrate and open the s o i l . P i o n e e r i n g , weedy species, such as Canada t h i s t l e , sow t h i s t l e and f o x t a i l b a r l e y , are b e n e f i c i a l i n t h i s regard. Subsequent and more d e s i r a b l e seedlings b e n e f i t from the improved s o i l s t r u c t u r e , and may a l s o b e n e f i t from the shading and p r o t e c t i o n from wind and geese t h a t t h i s v e g e t a t i o n a f f o r d s . Despite the b i o l o g i c a l value of noxious weeds as a nurse crop, the p o l i t i c a l costs a s s o c i a t e d w i t h these species have to be considered. Seeding the i s l a n d s i n e i t h e r e a r l y s p r i n g ( A p r i l to May) or l a t e f a l l (September to October) enhances establishment success i n dry years. E s t a b l i s h i n g v e g e t a t i o n i n extreme environments n e c e s s i t a t e s seeding at optimal or near optimal times. I d e a l l y the seedbed should be moist, w i t h good t i l t h . I f the s o i l i s clayey and unmulched, seeding i n t o wet s o i l i s i n a p p r o p r i a t e , because the wet s o i l b a l l s up and forms c l o d s . These clods subsequently harden and become v i r t u a l l y impenetrable to water or r o o t s . The d i f f i c u l t y i n handling sodic s o i l s was demonstrated when seeding i s l a n d s , i n a separate wetland, i n southern A l b e r t a (Fehr and P i t t 1988). These i s l a n d s were s a l i n e -s o d i c , but had been t r e a t e d w i t h manure and r o t o t i l l e d . Areas of the i s l a n d where manure was present and w e l l 162 i n c o r p o r a t e d were easy to seed and rake, even a f t e r a r a i n shower. Manure a p p l i c a t i o n , however, was patchy and s e v e r a l areas lacked manure. These areas were cloddy and hard when dry, and became extremely s t i c k y and unmanageable when only moist. The manured areas developed s t a b l e aggregates and macropore space, p e r m i t t i n g i n f i l t r a t i o n and h a n d l i n g . F e r t i l i s i n g i s l a n d s i s a management option f o r i s l a n d v e g e t a t i o n . The d e c i s i o n t o f e r t i l i s e must be considered c a r e f u l l y f o r two reasons. F i r s t , f e r t i l i s e r s a l t s can increase s a l i n i t y problems by i n c r e a s i n g osmotic s t r e s s around the seed. Secondly, f e r t i l i s i n g at seeding time may b e n e f i t only the p i o n e e r i n g species, s i n c e they can q u i c k l y e s t a b l i s h and u t i l i z e the n u t r i e n t s . T o t a l N had almost a p e r f e c t r e l a t i o n s h i p w i t h organic C ( r 2 = 0.99, P < 0.001). This suggests t h a t , compared to f e r t i l i s e r s , the a d d i t i o n of manure or some other organic m a t e r i a l w i l l have a l o n g - l a s t i n g e f f e c t t h a t improves the n u t r i e n t s t a t u s and p h y s i c a l c o n d i t i o n of the s o i l . Species s e l e c t i o n must be r e l a t e d to the i s l a n d c o n d i t i o n s encountered. Non-sodic and non-saline i s l a n d s can be seeded to a v a r i e t y of agronomic and n a t i v e species, i n c l u d i n g the species discussed i n t h i s r e p o r t . Under clayey and sodic or s a l i n e c o n d i t i o n s , species must be chosen to t o l e r a t e these c o n d i t i o n s . For example, t a l l wheatgrass, western wheatgrass (Agropyron smithii), slender wheatgrass (Agropyron trachycaulum), A l t a i w i l d r y e (Elymus 163 angustus) , Russian w i l d r y e (Elymus juncea) and kochia (Kochia scoparia) are a l l appropriate choices. In a d d i t i o n to herbaceous species, shrubs should be considered for- use on these man-made i s l a n d s . Shrubs provide good n e s t i n g cover, v e g e t a t i v e heterogeneity, and s o i l e r o s i o n c o n t r o l . Several species have p o t e n t i a l f o r i s l a n d use: western snowberry, p r i c k l y rose (Rosa acicularis), common w i l d rose, fourwing s a l t b u s h (Atriplex canescens), s i l v e r s a l t b u s h ( A t r i p l e x n u t t a l l i i ) , and kochia spp. (e.g. Kochia americana) . This l i s t i s not exhaustive and reclamation personnel should always be l o o k i n g f o r s u i t a b l e n a t i v e and agronomic species. A more complete d i s c u s s i o n of shrub use i s provided i n a report by Fehr and P i t t (1987). Herbaceous ve g e t a t i o n can be e s t a b l i s h e d not only by seeding, but a l s o by sodding, s p r i g g i n g and container-grown p l a n t s . These techniques, while more c o s t l y and labour-i n t e n s i v e than seeding, e l i m i n a t e the h i g h l y s e n s i t i v e stages of germination and root establishment, when m o r t a l i t y i s g r e a t e s t . Transplants a l s o provide immediate cover, w i t h normally high s u r v i v a l r a t e s . Success has been achieved by sodding and c o n t a i n e r - p l a n t i n g on many extreme a l p i n e s i t e s (Sims et a l . 1984). C o n t a i n e r - p l a n t i n g i s considered s u p e r i o r to s p r i g g i n g and sodding because the stock i s easy to handle, i s more r e s i s t a n t to d e s i c c a t i o n and disturbance, and produces seed a f t e r one growing season. These techniques are best used when quick establishment and cover 164 are r e q u i r e d , p a r t i c u l a r l y under severe p l a n t i n g c o n d i t i o n s . Complementing a seeding program wi t h sodding or c o n t a i n e r -p l a n t i n g might be a s u c c e s s f u l approach f o r i s l a n d s . As with any p l a n t i n g procedure, container stock must be s t o r e d p r o p e r l y , and t r a n s p l a n t e d at the appropriate time of year, p r e f e r a b l y when the p l a n t s are dormant. Water e r o s i o n causes s e r i o u s damage t o many DU i s l a n d s before they are vegetated. Improving v e g e t a t i o n establishment, through b e t t e r seeding techniques or t r a n s p l a n t s , w i l l reduce surface e r o s i o n and provide s t r u c t u r a l support f o r the i s l a n d . U n f o r t u n a t e l y , the unvegetated s h o r e l i n e s are d i r e c t l y exposed t o e r o s i v e wave a c t i o n , causing the i s l a n d s t o cut and slump. Using t r a n s p l a n t techniques, e r o s i o n could be reduced. Estab-l i s h i n g emergent and s h o r e l i n e v e g e t a t i o n on the windward si d e of i s l a n d s may be accomplished by t r a n s p l a n t i n g s p r i g s , rhizomes, or sod-clumps. P o t e n t i a l emergent species i n c l u d e a l k a l i , hard-stem and soft-stem bulrush, spike rush and c a t t a i l . P o t e n t i a l s h o r e l i n e species i n c l u d e salt-meadow grass, western wheatgrass, manna grass (Glyceria spp.), reed grass (Calamagrostis spp.), whitetop grass, and sedges. The most appropriate species depend on s i t e - s p e c i f i c s o i l and water c h a r a c t e r i s t i c s . 165 To make management d e c i s i o n s about i s l a n d reclamation, the s p o i l m a t e r i a l should be c h a r a c t e r i z e d . A number of c r i t e r i a should be used t o evaluate the s p o i l m a t e r i a l : 1) pH, 2) s a l i n i t y ( e l e c t r i c a l c o n d u c t i v i t y ) , 3) s o l u b l e c a t i o n s , 4) s o d i c i t y (SAR), and 5) organic carbon (Walkley-B l a c k ) . These analyses can be completed r e l a t i v e l y cheaply, yet a l l o w the manager to c h a r a c t e r i z e the s o i l as s o d i c , s a l i n e , s o d i c - s a l i n e , or n e i t h e r sodic or s a l i n e . From t h i s sampling, a course of management can be e s t a b l i s h e d . For example, i f analyses from the s p o i l m a t e r i a l i n d i c a t e a severe s o d i c i t y problem, the manager may decide against b u i l d i n g i s l a n d s , or decide to in c o r p o r a t e the cost of gypsum. Because C i s s t r o n g l y a s s o c i a t e d w i t h N, i t i s not necessary t o t e s t f o r both. Organic C i s a more f a m i l i a r measure and i s more r e a d i l y i n t e r p r e t a b l e . I t a l s o tends to be a l e s s c o s t l y t e s t . T e x t u r a l a n a l y s i s i s va l u a b l e , but expensive. Of most importance i s the amount of c l a y present i n the s p o i l . Knowing the % c l a y enables the manager to p r e d i c t the response of s o i l s to d i f f e r e n t a c t i o n s . Although BD i s a va l u a b l e property to know, i t i s expensive and time consuming. I t i s safe to assume that sodic s o i l s have poor s t r u c t u r e and probably r e q u i r e mulching. V i s u a l i n s p e c t i o n of the seedbed should be s u f f i c i e n t to decide i f r o t o t i l l i n g and mulching are needed. 166 I f a number of i s l a n d s are to be evaluated, a minimum of two s o i l samples should be taken from each i s l a n d . This l e v e l of sampling should be s u f f i c i e n t to e s t a b l i s h a management p l a n . I f the r e l a t i o n s h i p between s o i l s and ve g e t a t i o n i s d e s i r e d , the veg e t a t i o n can be sampled w i t h a nestingboard. 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Island Seeding His t o r i e s The following mixture was seeded on Butter Lake (22 kg/ha, seeded May 1981), Hebert Lake (22 kg/ha, November 1981), Houcher F l a t and Lake (39 kg/ha, October 1981), Marstrand Project (22 kg/ha, May 1981), Paulgaard Marsh (58 kg/ha, June 1981), and Reta Project (22 kg/ha, May 1981) islands: a l f a l f a (20% by mass), creeping red fescue (10%), crested wheatgrass (20%), smooth brome grass (15%), t a l l wheatgrass (25%), and yellow sweet clover (10%). The following mixture was seeded on Louis Lake (96 kg/ha) June 1982) and Zilke Marsh (17 kg/ha, June 1982) islands: a l f a l f a (20%), creeping red fescue (10%), crested wheatgrass (20%), intermediate wheatgrass (25%) smooth brome grass (15%) and yellow sweet clover (10%). Rollyview Marsh (45 kg/ha, May 1983) and Waskwei Creek (45 kg/ha, November 1982) islands were seeded with the following mixtures: a l f a l f a (10%), creeping red fescue (20%), crested wheatgrass (16%), smooth brome grass (20%) , t a l l wheatgrass (24%), and yellow sweet clover (10%). Kingston Slough islands (17 kg/ha, A p r i l and May 1980), were seeded to al s i k e clover (25%), intermediate wheatgrass (20%), smooth brome grass (45%), and yellow sweet clover (10%) . 179 B . L o c a t i o n s - o f study i s l a n d s i n wetlands. The study i s l a n d s are numbered. Le v e l d i t c h i n g i s represented by a broken l i n e and north i s at the top of the page. 180 181 182 183 184 11. Z i l k e Marsh 185 Appendix 2. Species recorded i n quadrats on i s l a n d s i n 1985 and 1986. Unless i n d i c a t e d by a date i n brackets, the species were recorded i n both years. Family and Species Common Name Typhaceae Typha latifolia Gramineae Agrohordeum macounii Agropyron cristatum Agropyron elongatum Agropyron intermedium Agropyron repens Agropyron trachycaulum Alopecurus aequalis Beckmannia syzigachne Bromus inermis Calamagrostis stricta Elymus sp. Festuca rubra Glyceria grandis Hordeum jubatum Poa p a l u s t r i s Poa pratensis P u c c i n e l l i a n u t t a l l i a n a Scolochloa festucacea Cyperaceae Carex atherodes Carex rostrata Carex sychnocephala Eleocharis p a l u s t r i s Scirpus acutus Scirpus paludosus Scirpus validus Juncaceae Juncus b a l t i c u s Juncus nodosus Polygonaceae Polygonum amphibium Rumex maritimus common c a t t a i l (1985! Macoun's w i l d r y e c r e s t e d wheatgrass t a l l wheatgrass intermediate wheatgrass quack grass (1985) slender wheatgrass (1985) water f o x t a i l (1985) slough grass smooth brome grass narrow reed grass w i l d r y e (1986) creeping red fescue t a l l manna grass (1985) f o x t a i l b a r l e y fowl bluegrass (1985) Kentucky bluegrass (1985) s a l t meadow grass whitetop grass awned sedge beaked sedge long-beaked sedge spike rush hardstem b u l r u s h a l k a l i b u l r u s h softstem b u l r u s h (1985) B a l t i c rush (1985) knotted rush (1985) water smartweed golden dock (1985] 186 Chenopodiaceae Chenopodium fremontii Chenopodium rubrum Chenopodium salinum Caryophyllaceae Stellaria longipes Ranunculaceae Ranunculus cymbalaria Ranunculus sceleratus C r u c i f e r a e Rorippa p a l u s t r i s Thlaspi arvense Rosaceae P o t e n t i l l a anserina P o t e n t i l l a norvegica Leguminosae Medicago sativa Melilotus officinalis Trifolium repens Onagraceae Epilobium ciliatum Hippuridaceae Hippuris vulgaris Primulaceae Glaux maritima Labiatae Galeopsis tetrahit Mentha arvensis Stachys p a l u s t r i s Plantaginaceae Plantago major Fremont's goosefoot red goosefoot oak-leaved goosefoot l o n g - s t a l k e d chickweed (1985) creeping buttercup cursed crowfoot (1985) yellow cress stinkweed (1985) sil v e r w e e d (1986) rough c i n q u e f o i l a l f a l f a y ellow sweet c l o v e r white c l o v e r northern willowherb (19 m a r e ' s - t a i l sea milkwort hemp n e t t l e (1985) w i l d mint hedge n e t t l e (1985) common p l a n t a i n (1986) 187 Compositiae Antennaria p a r v i f l o r a Artemisia absinthium Artemisia biennis Aster brachyactis Aster ericoides Aster hesperius . Cirsium arvensis Crepis tectorum Erigeron canadensis Erigeron lonchophyllus Senecio congestus Sonchus uliginosus Taraxacum officinale small-leaved e v e r l a s t i n g (1986) wormwood (1985) b i e n n i a l sagewort r a y l e s s a s t e r (1985) t u f t e d white p r a i r e a s t e r western w i l l o w a s t e r (1985) Canada t h i s t l e annual hawksbeard horseweed (1985) h i r s u t e fleabane (1985) marsh ragwort (1985) p e r e n n i a l sow t h i s t l e common dandelion 188 Appendix 3. Percent f o l i a r cover (not bracketed) and frequency ( i n brackets) of i n d i v i d u a l species on each i s l a n d and o v e r a l l , i n 1985 and 1986. a Species^ 3 B u t t e r Lake Hebert Lake 1985 1986 1985 1986 Islands I s l a n d Islands I s l a n d 1 2 1 1 2 1 AGCR 0(0/12) 0 (0/6) 0 (0/8) 1 (5/6) 2 (4/6) 1 (7/8) AGEL 1(3/12) 6 (1/6) 0 (3/8) 9 (6/6) 10 (6/6) 14(6/8) AGIN NS C NS NS NS NS NS BRIN 2(4/12) . 1 (2/6) 0 .8 (3/8) 4 (5/6) 3 (4/6) 0 .4 (7/8) CASP 4 (7/12) 14 (4/6) 2 (4/8) 0 (0/6) 0 (0/6) 0(0/8) CIAR 15(10/12) 6 (6/6) 24 (8/8) 0 (0/6) 0 (1/6) 0 (0/8) FERU 0.3.(1/12) 0 (2/6) 0 (2/8) 1 (2/6) 0.6 (2/6) 0 .4(6/8) HOJU 3(6/12) 7 (6/6) 0 .4 (5/8) 6 (3/6) 1 (5/6) 13 (5/8) MEOF 21(11/12) 0.3 (1/6) 0 (2/8) 9 (5/6) 8 (4/6) 12 (7/8) MESA 10(5/12) 0 (0/6) 0 (0/8) 0.6 (2/6) 1 (2/6) 0 -4 (2/8) PUNU 2 (3/12) 0 (0/6) 0 . 4 (2/8) 1 (4/6) 0 (3/6) 0 (2/8) SCFE 0(0/12) 0 (0/6) 0 (0/8) 0 (0/6) 0 (0/6) 0(0/8) SOUL 18(12/12) 19 (6/6) 34 (8/8) 0.6 (2/6) 2 (2/6) 1(5/8) Houcher F l a t Houcher Lake AGCR 0 (0/6) 0 (0/6) 0 (0/8) 0 (0/8) 0 (0/6) 0(0/8) AGEL 1 (3/6) 0.6 (1/6) 0 (0/8) 0 (3/8) 0.6(1/6) 0 .4 (2/8) AGIN NS NS NS NS NS NS BRIN 0 (2/6) 2 (2/6) 2 (3/8) 0 (2/8) 0.6 (4/6) 0 .4 (2/8) CASP 0 (0/6) 0 (0/6) 0 (1/8) 0 (0/8) 0 (0/6) 0 (0/8) CIAR 2 (4/6) 2 (5/6) 14 (8/8) 7 (7/8) 4(6/6) 12 (7/8) FERU 0(0/6) 0 (0/6) 0 (0/8) 0 (0/8) 0(0/6) 0(0/8) HOJU 20 (6/6) 25 (6/6) 9 (8/8) 6 (8/8) 1(4/6) 10(8/8) MEOF 2 (3/6) 0 (1/6) 2 (3/8) 22 (8/8) 0 (0/6) 20 (7/8) MESA 0 (0/6) 0 (0/6) 0 (0/8) 0 (1/8) 0 (0/6) 0 (1/8) PUNU 0 (1/6) 0 (0/6) 0 (1/8) 0 (1/8) 0 (2/6) 0 (0/8) SCFE 16 (5/6) 17 (5/6) 5 (6/8) 22 (8/8) 40 (6/6) 21 (8/8) SOUL 2 (6/6) 2 (6/6) 0 (1/8) 1 (7/8) • 3(6/6) 0 .4 (3/8) 189 Appendix 3. continued. Species Kingston Slough Louis Lake 1985 1986 1985 1986 Islands I s l a n d I slands I s l a n d 1 2 1 1 2 1 AGCR NS NS NS 0 (0/10) __d 0(0/8) AGEL NS NS NS NS NS NS AGIN 3 (5/6) 7(6/6) 3(8/8) 0 (0/10) — 0 (0/8) BRIN 1 (2/6) 0.6 (4/6) 1 (3/8) 0 (0/10) — 0 (0/8) CASP 0 (0/6) 0 (0/6) 0 (0/8) 0(3/10) — 0 (2/8) CIAR 0 (1/6) 0 (0/6) 0(0/8) 5 (8/10) — 28 (7/8) FERU NS NS NS 3 (10/10) — 4(8/8) HOJU 7 (6/6) 1 (5/6) 3 (8/8) 0 (2/10) — 0(0/8) ME OF 0 (0/6) 2 (2/6) 0(1/8) 11 (10/10) — 0(0/8) MESA NS NS NS 0 (0/10) -- 0(2/8) PUNU 3 (5/6) 3 (5/6) 5 (8/8) 0 (0/10) — 0(0/8) SCFE 0 (0/6) 0 (0/6) 0(0/8) 3 (.9/10) — 2 (4/8) SOUL 2(6/6) 0.6 (6/6) 5 (5/8) 23 (10/10) — 23 (8/8) Marstrand P r o i e c t Paulgaard Marsh AGCR 0(0/12) 0 (0/8) 0 (0/6) 0 (0/6) 0(0/8) AGEL 2(9/12) 3 (7/8) 27 (6/6) 22 (6/6) 45 (8/'8) AGIN NS NS NS NS NS BRIN 2(12/12) 5 (8/8) 2 (5/6) 0.6 (4/6) 4 (5/8) CASP 0.3(12/12) 3 (5/8) 0 (0/6) 0 (0/6) 0(0/8) CIAR 11(12/12) 17 (8/8) 0 (0/6) 0 (1/6) 0(0/8) FERU 0.6(5/12) 0 (4/8) 0. 6 (2/6) 0 (5/6) 1 (2/8) HOJU 0(0/12) 0 (0/8) 1 (5/6) 0 (5/6) 5(6/8) ME OF 0(0/12) 0 (0/8) 8 (5/6) 0 (0/6) 1 (3/8) MESA 0 (0/12) 0 (0/8) 0 (0/6) 0 (2/6) 0(0/8) PUNU 0(0/12) 0 (1/8) 1 (2/6) 0 . 6 (3/6) 1 (4/8) SCFE 1(3/12) 0 (0/8) 0 (0/6) 3 (3/6) 0(0/8) SOUL 10(12/12) .15 (8/8) 5 (6/6) 6(6/6) 5 (5/8) 190 Appendix 3. continued. Species Reta P r o i e c t e R o l l v v i e w Marsh 1985 1986 1985 1986 Islands I s l a n d I slands I s l a n d 1 2 1 1 2 1 AGCR 0 (0/6) 0(0/6) 0(2/6) 0 (0/8) AGEL 1 (3/6) — 4(6/6) 6(6/6) 11 (8/8) AGIN NS -- NS NS NS BRIN 2 (3/6) — 0(0/6) 0(0/6) 0 (1/8) CASP 9 (6/6) — 0(0/6) 0(0/6) 0(0/8) CIAR 6 (6/6) — 0(0/6) 0.(1/6) 0(0/8) FERU 0 (2/6) — 0(0/6) 0(0/6) 0 (0/8) HOJU 2 (3/6) — 0(0/6) 0(2/6) 0(0/8) MEOF 0 (1/6) — 0(0/6) 4(3/6) 0 (2/8) MESA 0 (0/6) — 0(0/6) 0(2/6) 0 (0/8) PUNU 0 (0/6) — 1(6/6) 1(5/6) 1(8/8) SCFE 0 (2/6) -- 0(0/6) 0(0/6) 0(0/8) SOUL 8 (6/6) — ~ 0(0/6) 0(0/6) 0 (0/8) Waskwei Creek Z i l k e Marsh AGCR 15 (10/12) 4 (6/8) 0 (0/10) 0 (0/8) AGEL 9(11/12) 3 (6/8) NS NS AGIN NS NS 1(8/10) 0 (2/8) BRIN 14 (11/1.2) 7 (7/8) 0 (0/10) 0 (2/8) CASP 12(7/12) 7 (4/8) 0 (0/10) 1 (3/8) CIAR 0 (0/12) 0 (2/8) 0.3 (1/10) 5(6/8) FERU 12(12/12) 21 (8/8) 11 (10/10) 14 (7/8) HOJU 0(3/12) 0 (0/8) 0 (5/10) 0(5/8) MEOF 4(11/12) 0 (3/8) 57 (10/10) 38 (8/8) MESA 1(5/12) 0 (0/8) 0 (0/10) 0(0/8) PUNU 0(0/12) 0 (0/8) 0(0/10) 6(4/8) SCFE 4 (8/12) 0 (0/8) 0 (0/10) 0 (0/8) SOUL 0(1/12) 1 (2/8) 0(1/10) 0(0/8) 191 Appendix 3. continued. Species Annual T o t a l s 1985 1986 Islands I s l a n d 1 2 1 AGCR 1.6 (15/94) 0.3(6/36) 0 .5 (13/80) AGEL 5.1 (50/74) 6.6 (21/36) 9 .6 (40/64) AGIN 1.1 (13/26) 7.0 (6/6) 1 . 0 (10/24) BRIN 2.4 (46/100) 1.1 (20/42) 1 . 9 (41/88) CASP 2.2(25/100) 2.0 (4/42) 1 .2 (19/88) CIAR 4.7 (49/100) 1.7 (20/42) 9 . 1 (46/88) FERU 3.0 (44/94) 0.6 (9/36) 4 .0 (37/80) HOJU 3.0 (39/100) 5.0 (33/42) 5 . 8 (45/88) MEOF 12.6(64/100) 2.0 (11/42) . 6 . 6 (36/88) MESA 1.4 (13/94) 0.2 (6/36) 0 .1 (5/80) PUNU 0.6(22/100) 0.6 (18/42) 1 .2 (30/88) SCFE 3.5 (35/100) 8.6(14/42) 2 .5(18/88) SOUL 6.8(69/100) 4.6(30/42) 7 .7 (48/88) Frequency i s the number of records of a species i n a quadrat over the t o t a l number of quadrats where i t could be found. F o l i a r cover was determined w i t h the p o i n t -i n t e r c e p t method. Species: AGCR - c r e s t e d wheatgrass, AGEL - t a l l wheatgrass, AGIN - intermediate wheatgrass, BRIN - smooth brome grass, CASP - sedge species, CIAR - Canada t h i s t l e , FERU - creeping red fescue, HOJU - f o x t a i l b a r l e y , MEOF -yellow sweet c l o v e r , MESA - a l f a l f a , PUNU — s a l t meadow grass, SCFE - whitetop grass, and SOUL - sow t h i s t l e . NS - Not seeded. Dashes i n d i c a t e that the i s l a n d s were not sampled. 1985 - Reta Islands 1 and 2 are combined. 1986 - not sampled. 192 

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