"Science, Faculty of"@en . "Botany, Department of"@en . "DSpace"@en . "UBCV"@en . "Ratcliffe, Marilyn Jean"@en . "2010-04-21T20:12:50Z"@en . "1983"@en . "Master of Science - MSc"@en . "University of British Columbia"@en . "Three major alpine plant communities were identified on Lakeview Mountain, Cathedral Provincial Park, using multivariate analysis of percentage cover data. Communities were dominated by Kobresia myosuroides, Carex scirpoidea (with one transitional area dominated by both Kobresia myosuroides and Carex scirpoidea), or by Carex scirpoidea and Carex capitata (with Salix nivalis as an additional dominant at one site). Community composition and distribution had little relationship with aspect or with the soils and microclimatic factors measured. Phenology was recorded for vascular species during the summer of 1980. Later flowering times were observed for a number of species in Kobresia myosuroides or Carex scirpoidea/Carex capitata dominated vegetation, and plants generally flowered earlier on southern aspects. Small scale patterns in the form of significant associations between species-pairs were detected in all communities, using a plotless point-line sampling technique. Patterns were abundant at this scale, with a total of 182 significant positive associations and 103 significant negative associations recorded between different species pairs. These interspecific associations varied considerably between sampled sites in the study area, with many occurring only once. Possible association-generating mechanisms have been discussed, and characteristics of the genotype, rather than the taxonomic species, have been suggested as critical in the formation of associations. A competitive hierarchy of dominant species has also been proposed, based on interspecific association and phenological data. Soils within the study area are classified as Alpine Dystric Brunisols, and are coarse textured, strongly acidic, low in available nutrients, and high in organic matter. Climate was relatively uniform over the study area during the 1980 growing season, as were microclimatic air and soil temperature profiles and air humidity profiles. Lower soil temperatures, however, occurred beneath Kobresia myosuroides dominated vegetation."@en . "https://circle.library.ubc.ca/rest/handle/2429/23995?expand=metadata"@en . "INTERSPECIFIC ASSOCIATIONS, PHENOLOGY, AND ENVIRONMENT OF SOME ALPINE PLANT COMMUNITIES ON LAKEVIEW MOUNTAIN, SOUTHERN BRITISH COLUMBIA by MARILYN JEAN RATCLIFFE B.Sc, The University. Of V i c t o r i a , 1979 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES Botany Department We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA July 1983 \u00C2\u00A9 Marilyn Jean R a t c l i f f e , 1983 J I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e h e a d o f my d e p a r t m e n t o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f BOTANY The U n i v e r s i t y o f B r i t i s h C o l u m b i a 1956 Main Mall V a n c o u v e r , Canada V6T 1Y3 D a t e JULY 29, 1983 DE-6 (3/81) i i Abstract Three major alpine plant communities were i d e n t i f i e d on Lakeview Mountain, Cathedral Provincial Park, using multivariate analysis of percentage cover data. Communities were dominated by Kobresia myosuroides, Carex scirpoidea (with one t r a n s i t i o n a l area dominated by both Kobresia myosuroides and Carex scirpoidea), or by Carex scirpoidea and Carex capitata (with Salix n i v a l i s as an additional dominant at one s i t e ) . Community composition and d i s t r i b u t i o n had l i t t l e r elationship with aspect or with the s o i l s and microclimatic factors measured. Phenology was recorded for vascular species during the summer of 1980. Later flowering times were observed for a number of species in Kobresia myosuroides or Carex scirpoidea/Carex capitata dominated vegetation, and plants generally flowered e a r l i e r on southern aspects. Small scale patterns in the form of s i g n i f i c a n t associations between species-pairs were detected in a l l communities, using a p l o t l e s s p o i n t - l i n e sampling technique. Patterns were abundant at t h i s scale, with a t o t a l of 182 s i g n i f i c a n t p o s i t i v e associations and 103 s i g n i f i c a n t negative associations recorded between di f f e r e n t species pa i r s . These i n t e r s p e c i f i c associations varied considerably between sampled s i t e s in the study area, with many occurring only once. Possible association-generating mechanisms have been discussed, and c h a r a c t e r i s t i c s of the genotype, rather than the taxonomic species, have been suggested as c r i t i c a l in the formation of associations. A competitive hierarchy of dominant species has also been proposed, based on i n t e r s p e c i f i c association and phenological data. S o i l s within the study area are c l a s s i f i e d as Alpine Dystric Brunisols, and are coarse textured, strongly a c i d i c , low in available nutrients, and high in organic matter. Climate was r e l a t i v e l y uniform over the study area during the 1980 growing season, as were microclimatic a i r and s o i l temperature p r o f i l e s and a i r humidity p r o f i l e s . Lower s o i l temperatures, however, occurred beneath Kobresia myosuroides dominated vegetation. iv Table of Contents Abstract i i L i s t of Tables v i L i s t of Figures v i i Acknowledgements v i i i I. INTRODUCTION 1 THE ALPINE ZONE 2 LITERATURE REVIEW 4 OBJECTIVES 10 11 . STUDY AREA 11 LOCATION 11 LAND USE 13 GEOLOGY AND GEOMORPHOLOGY 15 GEOLOGY 15 GEOLOGICAL HISTORY 15 SOILS 16 CLIMATE 17 VEGETATION 18 ANIMALS 23 II I . METHODS 24 VEGETATION 24 TRANSECT PLACEMENT 24 QUADRAT SAMPLING DESIGN 26 ANALYSES OF QUADRAT DATA 28 POINT-LINE SAMPLING 33 ANALYSIS OF POINT-LINE DATA 34 PHENOLOGY 38 NOMENCLATURE 39 SOILS 39 CLIMATE 41 IV. RESULTS 43 VEGETATION 43 COMMUNITY TYPES 43 1 . Transect A: 43 2. Transect B: 46 3. Transect C: 48 4. Transect D: 51 5. Transect E: ..........54 6. Transect F: 57 7. A l l Transects: ..60 PHENOLOGY 67 1. Constant Aspect: ...74 2. Constant Community Type: 75 INTERSPECIFIC ASSOCIATIONS 77 1 . Transect A: 78 2. Transect B: ..' 81 3. Transect C: 81 4. Transect D: .84 5. Transect E: 90 6. Transect F: 93 7. A l l Transects: 97 POSITIVE ASSOCIATIONS: 97 V NEGATIVE ASSOCIATIONS: 115 CONSTANCY OF INTERSPECIFIC ASSOCIATIONS 129 SPECIES ORDINATIONS 132 SOILS 135 MORPHOLOGY 135 PHYSICAL AND CHEMICAL PROPERTIES 135 CLIMATE 138 MESOCLIMATE 138 MICROCLIMATE 138 V. DISCUSSION 146 COMMUNITIES 146 PHENOLOGY 150 INTERSPECIFIC ASSOCIATIONS 152 POSSIBLE MECHANISMS GENERATING POSITIVE ASSOCIATION 154 1. Niche D i f f e r e n t i a t i o n : 154 2. Balanced Competitive A b i l i t i e s : 158 3. Additional Mechanisms: 159 POSSIBLE MECHANISMS GENERATING NEGATIVE ASSOCIATION164 1. Morphology: 1 64 2. Abiotic E f f e c t s : 164 3. Competitive Exclusion: 165 GENOTYPIC RESPONSE 168 DOMINANT SPECIES 170 SOILS 175 CLIMATE 176 CONCLUSIONS 178 VI . SUMMARY 181 VEGETATION 181 SOILS 184 CLIMATE 184 VII. LITERATURE CITED 185 APPENDIX A - GEOLOGICAL HISTORY 213 APPENDIX B - SOILS 215 APPENDIX C - PERCENTAGE COVER DATA FOR SIX TRANSECTS ....217 APPENDIX D - PRINCIPAL COMPONENTS ANALYSIS OF SOIL DATA .224 v i L i s t of Tables I. Selected Climatic Data for Weather Stations in Southern B r i t i s h Columbia (within the 1941-1970 period) . 19 I I . Transect C h a r a c t e r i s t i c s 24 I I I . Methodology for Physical and Chemical S o i l Analyses 40 IV. Associated Species 77 V. Positive Associations for 11 Sample Groups 98 VI. Negative Associations for 11 Sample Groups 116 VII. Constancy of Positive Associations 130 VIII. Constancy of Negative Associations 131 IX. Species Pairs Associated Both P o s i t i v e l y and Negatively in Different Vegetation Groups 133 X. Physical and Chemical Properties from S o i l P r o f i l e s within 11 Vegetation Groups 136 XI. Mesoclimatic Data For Three Weather Stations, 1: S84\u00C2\u00B0W, 2481 m; 2: S2\u00C2\u00B0E, 2402 m; and 3: N29\u00C2\u00B0E, 2475 m. 139 v i i L i s t of Figures 1. Location of Study Site in Cathedral Provincial Park, B r i t i s h Columbia ..12 2. Position of Transects (A-F) in the Study Site 25 3. Quadrat Sampling Design 27 4. Transect A Multivariate Analyses 44 5. Transect B Multivariate Analyses 47 6. Transect C Multivariate Analyses 50 7. Transect D Multivariate Analyses 53 8. Transect E Multivariate Analyses 56 9. Transect F Multivariate Analyses 58 10. Centered PCA - A l l Data Sets 62 11. Centered and Standardized PCA - A l l Data Sets 63 12. RA - A l l Data Sets 64 13. Cluster Analysis - A l l Data Sets 66 14. Transect A Phenology 69 15. Transect B Phenology 69 16. Transect C Phenology 70 17. Transect D Phenology 71 18. Transect E Phenology 72 19. Transect F Phenology 73 20. Group A Positive and Negative Associations 80 21. Group B Positive and Negative Associations 82 22. Group C1 Positive and Negative Associations 83 23. Group C2 Positive and Negative Associations 85 24. Group D1 Positive and Negative Associations 87 25. Group D2 Positive and Negative Associations 88 26. Group D3 Positive and Negative Associations 89 27. Group E1 Positive and Negative Associations 91 28\". Group E2 Positive and Negative Associations ....92 29. Group F1 Positive and Negative Associations 94 30. Group F2 Positive Associations 95 31. Group F2 Negative Associations 96 32. Microclimatic data for 11 vegetation groups during summer 1980 140 v i i i Acknowledgement I wish to thank my supervisor, Dr. Roy Turkington, for his assistance, enthusiasm, and guidance throughout the course of t h i s study. Thanks are also extended to my commitee members, Drs. G. Bradfield and J. Maze, for providing valuable suggestions and c r i t i c a l l y reviewing the manuscript. I am grateful to Drs. Piet de Jong and Malcom Greig for s t a t i s t i c a l consultation, and to Dr. T. Ballard for advice regarding s o i l sampling and analysis and for providing laboratory f a c i l i t i e s . The computer program for analysis of i n t e r s p e c i f i c associations was written by Dave Zitton. I also thank Barry Wong and John Emanuael for computing consultation. Aid in the i d e n t i f i c a t i o n and v e r i f i c a t i o n of plant species was provided by Dr. G.W. Douglas and Terry Mcintosh. Immeasurable appreciation i s extended to Dr. G.W. Douglas for providing advice, i n s p i r a t i o n , and unt i r i n g interest during this research, p a r t i c u l a r l y in the f i r s t f i e l d season. I also thank George A. Douglas, Mr. A.G. R a t c l i f f e , Melanie M a d i l l , and Angela Chen for f i e l d and data manipulation assistance, and Tom Fleet and Karl Gehringer of Cathedral Lakes Resort for their interest in the study ix and for their friendship. F i n a l l y , very special thanks are due to Dr. K. Wilf N i c h o l l s . His assistance with f i n a l figures and, most importantly, his u n f a i l i n g patience, support, and understanding, made the completion of t h i s thesis possible. Financial assistance through a National Science and Engineering Research Council of Canada postgraduate scholarship i s g r a t e f u l l y acknowledged. 1 I . INTRODUCTION Alpine vegetation ecology has been e s s e n t i a l l y limited to the consideration of community patterns in r e l a t i o n to abio t i c factors, such as time of snow release, microclimate, and physical and chemical properties of the s o i l . Savile (1960) has stated that in severe environments such as the alpine, competition i s unimportant compared to physical factors, \"allowing e s s e n t i a l l y random occurrence of plants without d i s t i n c t associations and frequent coexistence of related species that have extremely similar requirements\". This opinion is supported by B l i s s (1962). Whittaker (1975) argued along similar l i n e s and considered evolution to be affected more strongly by selection for survival in rel a t i o n to problems of the physical environment and less strongly by selection involving interaction and competition with other species. Even Darwin (1859), who emphatically stressed the importance of b i o t i c factors such as competition, considered the \"struggle for l i f e \" to be almost exclusively with the elements when one reached the \"a r c t i c regions or snow-capped summits\". As well, studies of pattern in the alpine zone have mainly been done on a large community scale, with small-scale pattern within communities and b i o t i c interactions between neighbouring species rarely being investigated. In t e r r e s t r i a l ecosystems other than the alpine, however, the study of small-scale pattern or non-random species d i s t r i b u t i o n s within plant communities has received much attention. This pattern has been attributed to both abi o t i c 2 (Blaser and Brady 1950, Harper and Sagar 1953, Snaydon 1962) and b i o t i c factors (Watt 1947, Harper e_t a l . 1961, Mack and Harper 1976, Turkington and Harper 1979). In view of the lack of this type of approach in the alpine zone, and the untested assumptions of many workers, the study of small-scale pattern within alpine communities merits attention. THE ALPINE ZONE The term \"alpine\" i s defined here as the area above the elevational l i m i t of upright trees, where tree species, i f present, assume a dwarfed or krummholz appearance (Douglas and B l i s s 1977). This d e f i n i t i o n has wide application in the northern hemisphere and i s similar to an e a r l i e r recommendation made by Love (1970). The alpine zone may begin at elevations as low as 300 m in the extreme north, or as high as 3500-4000 m in t r o p i c a l areas, where a l t i t u d e compensates for latitude in lowering the average temperature ( B i l l i n g s 1974a). The alpine zone in the southern i n t e r i o r of B r i t i s h Columbia begins at approximately 2200 m. The alpine climate i s characterized by cool temperatures, both in winter and summer. With increasing a l t i t u d e , the temperature of the ambient a i r decreases at an average rate of 5-6\u00C2\u00B0 C per 1000 m, with a corresponding decrease in the diurnal temperature range ( B i l l i n g s 1973, Barry and Van Wie 1974, Bennett 1976). Mean annual temperatures, for example, can be as low as -2\u00C2\u00B0 C, with d a i l y maximums of 10-11\u00C2\u00B0 C for June through August, in south-central B r i t i s h Columbia 3 (B.C. Dept. Agri. 1974). The low density of the alpine atmosphere lessens i t s a b i l i t y to store heat (Bennett 1976), and the v e l o c i t y of wind increases with increasing a l t i t u d e , due to thermal discontinuity ( T r a n q u i l l i n i 1964, Flohn 1974). The intensity of solar radiation, p a r t i c u l a r l y in the u l t r a v i o l e t (U.V.) spectrum, also increases with a l t i t u d e ( i . e . , on average, a 50% increase in clear-sky U.V. from sea l e v e l to 3650 m in elevation) (Gates and Janke 1966, Caldwell 1968) and i s primarily due to a decrease in atmospheric scattering and absorption capacity (Terjung et a l . 1969, Barry and Van Wie 1974). P r e c i p i t a t i o n generally tends to increase with a l t i t u d e in mid-latitude mountains due to a i r mass l i f t i n g and cooling (Flohn 1974), and results in a high degree of snow accumulation compared to lower elevations (Barry and Van Wie 1974). Due to snow accumulation, the growing season for alpine plants rarely exceeds 90 days in mid-latitude areas ( B i l l i n g s 1973). Alpine areas are characterized by a r e l a t i v e l y small number of perennial vascular plant species, which include both evergreen and herbaceous growth forms. A t o t a l of 170 alpine vascular species have been reported from the Rocky Mountains of Colorado (Holm 1927), and 165 have been recorded for the eastern North Cascade Range in Washington and B r i t i s h Columbia (Douglas and B l i s s 1977). Rosette species, sedges, grasses, cushion plants, lichens, and mosses are common, with most species assuming a prostrate or dwarf growth form (B l i s s 1969, B i l l i n g s 1974a). The heterogeneity of alpine microtopography often results in marked changes in physical factors such as s o i l 4 temperature and moisture, depth of thaw, wind speed, and snowpack over distances of only a few centimeters (Marr 1961, B i l l i n g s 1973, B i l l i n g s 1974a). Steep environmental gradients such as th i s result in abrupt changes between plant communities, while areas with more gradual environmental changes tend to have t r a n s i t i o n zones between communities. (Bliss 1969). This mixture of abrupt and gradual environmental changes i s ref l e c t e d in a mosaic of r e l a t i v e l y small and often discrete communities over the landscape. LITERATURE REVIEW Plant ecologists have been investigating various aspects of the vegetation of alpine zones in North America since the early 1900's, e.g., Cooper (1908), Taylor (1922), Cox (1933), and Whitfield (1933). The majority of these studies emphasize community patterns and associated environmental parameters ( B l i s s 1956, B i l l i n g s and B l i s s 1959, Johnson and B i l l i n g s 1962, Mooney et a_l. 1962, Archer 1963, B l i s s 1963, Scott and B i l l i n g s 1964, K l i k o f f 1965, Beder 1967, Marr 1967, Bamberg and Major 1968, Eady 1971, Knapik et a l . 1973, Crack 1977, Douglas and B l i s s 1977, Hrapko and La Roi 1978, Helm 1982), and have been recently reviewed by B l i s s (1969). A few alpine studies document c y c l i c vegetation dynamics in r e l a t i o n to environmental factors such as freeze/thaw phenomena ( B i l l i n g s and Mooney 1959, Johnson and B i l l i n g s 1962, Mark and B l i s s 1970). This emphasis on community-orientated studies appears to be due to at least two factors. F i r s t , the v i s u a l l y obvious vegetation patterns 5 i n v i t e study, and t h e i r description i s a f i r s t step in ecological investigations. Second, the emphasis on a b i o t i c factors may be p a r t i a l l y due to alpine climatic extremes which are often severe from a human standpoint. This leads to the natural assumption that these conditions must be \"harsh\" or \" s t r e s s f u l \" for the plants, and therefore important determinants of d i s t r i b u t i o n . Alpine studies that have sh i f t e d emphasis away from community description f a l l into two camps. F i r s t , there are those that have considered the role of competition in vegetation that forms closed swards (Rochow 1970, B i l l i n g s 1974a, Callaghan 1976), but work in t h i s area has been extremely li m i t e d . Shaver et a l . (1979) have studied intergenotypic competition in Carex a q u a t i l i s Wahl. populations in a r c t i c vegetation. Grime (1979), however, uses a r c t i c and alpine vegetation as an example of stress-tolerant (S-selection) plants and suggests that competition (refering exclusively to the capture of resources) is r e l a t i v e l y unimportant in such high stress environments. Second, studies concerned with various functional or physiological aspects of the vegetation are common. For example, r e l a t i v e l y low photosynthetic temperature optima of 15\u00C2\u00B0 C - 20\u00C2\u00B0 C have been reported for alpine species (Hadley and B l i s s 1964, Mooney et a_l. 1964, Scott and B i l l i n g s 1964, Mark 1975), with vascular plant photosynthesis recorded at temperatures as low as 3\u00C2\u00B0 C (Anderson and McNaughton 1973) and -5\u00C2\u00B0 C (Mark 1975). Increased l i g h t i n t e n s i t i e s in the alpine l i k e l y contribute to the rapid summer growth rates ( T r a n q u i l l i n i 6 1964, Tieszen and Bonde 1967, B i l l i n g s 1974a). In Colorado, for example, the average growth rate of Saxifraga rhomboidea Greene early in the growing season- was 3.5 cm/week, while maximum peduncle elongation rates of 14 cm/week have been recorded for Polygonum bistortoides Pursh (Holway and Ward 1965). Due to thi s rapid growth, daily productivity rates for alpine herbaceous perennials are quite similar to those found for more temperate ecosystems ( B l i s s 1966), although average annual productivity of alpine vegetation as a whole i s comparatively low (Lieth 1975). For example, in the Wyoming alpine, values range from 1.2 g/m2/day on xeric s i t e s to 11.1 g/m2/day on mesic s i t e s (Scott and B i l l i n g s 1964), which i s comparable to values reported for temperate f i e l d situations (Odum 1 960, Ovington e_t a l . 1963). As well, alpine plants generally exhibit higher root and shoot respiration rates than do species from lower elevations (Mooney 1963, K l i k o f f 1968, Higgins and Spomer 1976), which has been interpreted as a metabolic adaptation to survival in cold temperatures (Mooney e_t al. 1964). In view of the physiological s p e c i a l i z a t i o n s found in alpine species, i t does not seem prudent to rule out the p o s s i b i l i t y of competitive interactions, p a r t i c u l a r l y since resources, such as available s o i l nutrients, may be in short supply (Bliss 1963, Nimlos and McConnell 1965, van Ryswk 1969, Bockheim 1972, Sneddon et a l . 1972, Knapik et a l . 1973). Recently, there has been a s h i f t in the nature of general plant ecological research from the early study of communities and continua (e.g., Clements 1904, Gleason 1926, Braun-Blanquet 7 1932, Tansley 1939), to the study of small-scale vegetation pattern involving populations of individuals within communities. A very limited number of early population and experimental studies were done (Tansley 1917, Clements and Weaver 1924, Sukatshew 1928), followed by approximately t h i r t y years in which this approach was v i r t u a l l y disregarded by plant ecologists, although population studies continued in systematics and the applied sciences of forestry and agriculture. The problem of i d e n t i f y i n g individuals and the lack of communication between investigators of natural vegetation and those of managed systems have been postulated by Harper (1977a) as possible reasons for th i s gap within plant ecology research. The population and individual approach has gained increasing popularity since the investigation by Watt (1947) of processes at t h i s scale within plant communities (see Newman 1982a). The methods used to describe and detect pattern have changed as the d e t a i l of enquiry by investigators has changed. V i s u a l l y obvious community patterns were i n i t i a l l y recorded subjectively. This was followed by more detailed scrutiny with species presence/absence or percentage cover recorded in quadrats or along a transect of points (Greig-Smith 1964). Patterns within grassland communities based on random or contiguous quadrat data have been documented by early ecologists (Blackman 1935, Clapham 1936, Archibald 1948). Later studies attributed small-scale patterns to such factors as s o i l nutrients (Blaser and Brady 1950, Kershaw 1958, 1959), s o i l pH (Snaydon 1962), microtopography (Harper and Sagar 1953, Kershaw 8 1963), species morphology (Kershaw 1963), and c y c l i c regeneration of species (Watt 1947, Goodall 1952, Greig-Smith 1952). The concept of plant species themselves influencing pattern has also been considered (Harper et al. 1961, Harper 1964, 1967). This conventional, quadrat approach has been c r i t i s i z e d by Greig-Smith (1961) who stated that the scale of study ( i . e . , the quadrat) i s imposed by the investigator and has l i t t l e relevance to the organisms l i v i n g within i t . Recently, a finer scale of discrimination considering above-ground physical contacts between di f f e r e n t species has been employed. This method detects patterns between species at the scale of the individual and has been used in bryophyte/1ichen communities (Yarranton 1966), and in temperate grasslands (Turkington et a l . 1977, Aarssen et a l . 1979, Turkington and Harper 1979a,b, Aarssen 1983). This methodology indicates a p a r t i c u l a r type of small-scale structure, which suggests, by i t s very nature, possible c a u s a l i t i e s . B i o t i c interactions between species (e.g., competition) and d i f f e r e n t i a l use of resources have been suggested as important factors influencing pattern in these studies. I n t e r s p e c i f i c associations do not prove the existence of b i o t i c interaction, but i t i s unlikely, for example, that two individuals growing in physical contact are not influencing each other to some degree. For example, Ross and Harper (1972) found the growth of individual Dactylis glomerata L. seedlings was greatly influenced by the distance and morphology of neighbouring plants, while Mack and Harper (1977) found proximity and placement of neighbouring species accounted for 9 69% of the growth and reproductive variation in a sand dune annual. Attitudes of plant ecologists are seemingly dependent on the scale of investigation. Harper and his students have been largely responsible for redirecting emphasis to the ecology of plant populations rather than communities and to the consideration of the role of natural selection in maintaining and changing these populations. As natural selection affects the i n d i v i d u a l , and evolution occurs within populations, the community i s determined by processes operating at the individual and populational l e v e l s . It is necessary to determine the processes that generate patterns in order to understand the structure of a community (Ricklefs 1979). Description alone w i l l not accomplish t h i s . The community as a \"whole\" must also be considered, however, as the evolution and variation of each species i s related to the community (Mcintosh 1970), and studies of species in i s o l a t i o n may have l i t t l e relevance to the behavior of the species in a community context. Greig-Smith (1979) has stressed the importance of bridging the gap between community and population ecology, stating that vegetation pattern i s a continuum of both scale and intensity, begining with the growth form of the i n d i v i d u a l . 10 OBJECTIVES The primary objective of this thesis i s to determine the nature and extent of patterning at a small scale within alpine plant communities, and to compare t h i s , as well as large-scale community patterns, to measured abio t i c and phenological data. It is hypothesized that vegetation patterns may, to some extent, be influenced by the plant species themselves. S p e c i f i c a l l y , the study objectives are to: (1) detect small-scale patterns in alpine vegetation, using a modified method of i n t e r s p e c i f i c association analysis for point sampling data; (2) relate s i g n i f i c a n t (p<0.05) i n t e r s p e c i f i c associations to community composition and phenology; (3) relate i n t e r s p e c i f i c associations and community composition to aspect, s o i l physical and chemical properties, and microclimate; and (4) interpret the results in terms of various a b i o t i c or b i o t i c processes p o t e n t i a l l y c o n t r o l l i n g species patterns in alpine vegetation. 11 II. STUDY AREA LOCATION The alpine zone of Lakeview Mountain in Cathedral Provincial Park, B r i t i s h Columbia, was chosen for study. Lakeview Mountain i s part of the Okanogan Range in the north-eastern portion of the Cascade Mountains, and i s located in the southern i n t e r i o r of B r i t i s h Columbia, at approximately 49\u00C2\u00B003'N, 120\u00C2\u00B009'W, just north of the Washington-British Columbia border (Fig. 1). The Cascade Mountains are separated from the Coast Mountains to the north by the Fraser River and merge into the Kamloops plateau to the east; they extend from th i s point through to southern Oregon. The alpine zone of Lakeview Mountain ranges from approximately 2200 m to 2600 m in elevation, and has continuous vegetation interspersed with boulder f i e l d s , rock r i v e r s , stone polygons, and other forms of patterned ground. The study s i t e l i e s to the north-east of Lakeview peak (Fig. 1), and has an elevation range of 2402 - 2500 m. This area was chosen for i t s r e l a t i v e l y diverse and continous dry sedge vegetation, present on v i r t u a l l y a l l aspects, and for the comparatively long snowfree or growing season. More western alpine areas are characterized by greater snow accumulation, later snowmelt, and r e l a t i v e l y cold, wet summers. In addition, species composition often changes more gradually in the eastern Cascades as environmental gradients are not as steep compared to more western areas (Douglas and B l i s s 1977). 1 2 Figure 1 - Location of Study Site in Cathedral Provincial Par B r i t i s h Columbia Br^TISH_CC^MBIA, CANADA . WASHINGTON~USA~ i _ 1 13 LAND USE On May 2, 1968, 16,480 ha of land were established as Cathedral Pr o v i n c i a l Park, 30 years after i t was f i r s t proposed. On May 6, 1969 an additional 703 ha were included, which previously contained mineral claims (Cartwright 1970). On September 11, 1975, approximately 25,911 ha were added to the park and the present area now comprises 33,468 ha (R.R. Howie pers. comm.). Cathedral Pr o v i n c i a l Park i s managed as a class 'A' wilderness park by the B r i t i s h Columbia Parks Branch, Dept. of Recreation and Conservation, with recreation as the primary use (Cartwright 1970). The park completely encloses a small recreational reserve in the Haystack Lakes area (Fig. 1), where management does not exclude resource extraction should t h i s later become feasible (Travers 1975). The Cathedral Lakes area has been used for recreation (e.g., hunting) since the late 1930's. In 1967, the main cabins of Cathedral Lakes Resort were b u i l t , and non-hunting, paying guests began to v i s i t the area ( B i l l Fleet pers. comm.). There is no motorized public access, although hiking t r a i l s are available and transport may be obtained through Cathedral Lakes Resort, which s t i l l retains two small l o t s within the park boundaries. An estimated 749 v i s i t o r s use the park annually (D a l z i e l 1971), but t h i s was before the main lodge was completed, and i s a modest estimate for present day use. Major a c t i v i t i e s for park v i s i t o r s include camping, f i s h i n g , and hiking (Cartwright 1970). The alpine and subalpine meadows within the park have had a 1 4 history of grazing by domestic sheep and c a t t l e . In the late 19'th and early 20'th century, sheep were grazed in the alpine zone (Cartwright 1970), with subsequent sheep grazing occurring for approximately 10 years in the 1940's, in both alpine and subalpine areas (Tom Fleet pers. comm.). Sheep were then replaced by c a t t l e , and grazing was generally limited to montane and subalpine meadows, with a few strays sometimes reaching the alpine zone ( B i l l Fleet pers. comm.). The class 'A' status of Cathedral Park excludes the grazing of domestic animals, although two leases in the park currently permit the grazing of 157 head of c a t t l e , the number maintained in the area before park establishment (R.R. Howie pers. comm.). The permit held by the Terbasket family includes the alpine zone on the east side of Lakeview Mountain, although t h i s area i s rarely used. Cathedral Park is not considered key rangeland for any major w i l d l i f e species, but i t is adjacent to range for a remnant herd of C a l i f o r n i a Bighorn Sheep (350-400 individuals) and hunting i s allowed in the park between August 31 and September 13 (Travers 1975). Recent disturbance within Cathedral Provincial Park appears limited to hiking, grazing, and frequent small f i r e s , caused primarily by lightning. Open, eroding s o i l p i t s carelessly l e f t by a previous researcher are an additional disturbance in the alpine zone of Lakeview Mountain. 15 GEOLOGY AND GEOMORPHOLOGY Geology The Cascade Mountains are characterized by folded, metamorphosed sedimentary \ and volcanic rocks of Paleozoic and Mesozoic o r i g i n , with intrusions of gr a n i t i c and granodiorite batholiths (Holland 1964, McTaggart : 1970). Paleozoic sedimentary and volcanic -rocks include a r g i l l i t e , cherty a r g i l l i t e , limestone, quartzite, andesite, and volcanic breccia. Mesozoic intrusive rock includes granodiorite, quartz monzonite, quartz d i o r i t e , granite, and syenite (Geol. Map Can., 1955). Most of the Princeton Map area (which includes Cathedral Park) is underlain by intrusive and extrusive igneous rocks (Rice 1960). Bodies of \"red\" and \"white\" granodiorite have been found, in addition to \"grey\", in the Cathedral Park area and are p a r t i a l l y derived from g r a n i t i z a t i o n of volcanic rocks (Rice 1960). Four geologic group members are exposed in Cathedral Park (1) Permian sediments, (2) T r i a s s i c lava, (3) Jurassic g r a n i t i c plutons, and (4) Eocene (Tertiary) sediments and volcanic material (Melcon 1975). Geological History Prior to the Pleistocene epoch, the Cascade Mountains experienced periods of marine sedimentation, vulcanism, compression, folding, erosion, and u p l i f t (Daly 1912, Rice 1960, Rudkin 1964, McTaggart 1970). It i s l i k e l y that the Pleistocene ice sheets did not at t a i n elevations over 2134 m in southern 16 B.C. (Nasmith 1962, Holland 1964), although Melcon (1975) gives evidence for a 2286-2377 upper l i m i t . Alpine g l a c i a t i o n , however, was extensive. S u r f i c i a l ash deposits from the late Pliocene to Recent times have been reported within and to the south of the study area (e.g., Powers and Wilcox 1964, F r y x e l l 1965, Wilcox 1965, van Ryswyk 1969, Bockheim 1972). A more detailed account of the geological history of Cathedral Pr o v i n c i a l Park i s given in Appendix A. Lesser landforms or microtopographical features within the study area on Lakeview Mountain include tors in areas of quartz monzonite bedrock (Melcon 1975) and patterned ground such as sorted stone polygons and stone s t r i p e s . Talus areas and felsenmeer of broken balsalt also occur. The majority of these features originated in p e r i g l a c i a l conditions accompanying the Fraser g l a c i a t i o n (Melcon 1975) and continue today as a result of frost action. Frost hummocks and s o l u f l u c t i o n lobes occur on lower alpine slopes where s o i l moisture i s adequate and result from freeze-thaw cycles in conjunction with gravity. SOILS S o i l s within the alpine zone of Lakeview Mountain have been examined in d e t a i l by van Ryswk (1969), who characterized the most extensive s o i l type as Alpine Brown with discontinuous ash layers - comparable to the Alpine Dystric Brunisol of the Canadian System. Structure s o i l s such as sorted stone patterns and stone r i v e r s are also found on Lakeview Mountain, as well as broken 17 rock, rock headwall, and talus units. A l l s o i l s have been influenced by volcanic ash, burying and mixing of horizons, frost heaving, s o l u f l u c t i o n , surface erosion, and c o l l u v i a l a c t i v i t y (van Ryswk 1969). Slow rates of chemical weathering due to cold temperatures and the erosive action of physical processes contribute to the general immaturity of s o i l p r o f i l e s found in alpine areas (Retzer 1974). Buried charcoal fragments (van Ryswyk 1971) may indicate that the tr e e l i n e was at higher elevations in the past (van Ryswyk and Okazaki 1979). A more detailed account of s o i l types within the study area i s presented in Appendix B. CLIMATE The study area l i e s within the south i n t e r i o r c l i m a t i c region of B r i t i s h Columbia described by Kendrew and Kerr (1955), which extends from the crest of the Coast Mountains east to the Rockies, and from the 49'th p a r a l l e l north to Prince George. The climate i s c l a s s i f i e d as mild continental with warm summers, cold winters, and low p r e c i p i t a t i o n due to the rainshadow e f f e c t of the Coast and Cascade Mountains. P r e c i p i t a t i o n i s well d i s t r i b u t e d over the year with some snow during winter and thunderstorms with rain and h a i l common in summer. Diurnal and seasonal temperature ranges are more extreme than those found in coastal areas to the west (Chilton 1981). Altitude and s i t e exposure can cause considerable variation within t h i s climatic regime. The closest weather stations to the study area are at 18 Hedley Nickle Plate (49\u00C2\u00B020'N, 119\u00C2\u00B059'W) and Hedley (49\u00C2\u00B021'N, 120\u00C2\u00B005'W), both approximately 50 km from the study s i t e . Selected climatic data for these stations i s shown in Table I., which includes data from the Old Glory weather station (49\u00C2\u00B009'N, 117\u00C2\u00B055'W), 160 km to the east. The Old Glory station is located above the tr e e l i n e and i s within the south i n t e r i o r c limatic region. It i s the closest approximation to the alpine climate on Lakeview Mountain. VEGETATION The alpine zone of Lakeview Mountain i s characterized by r e l a t i v e l y diverse dry sedge vegetation, with an average of 30-35 vascular plant species and 20-30 lichen and moss species occurring with each dominant. The t r e e l i n e i s at approximately 2200 m, with vegetation below this point dominated' by Abies lasiocarpa (Hook.) Nutt., Picea engelmani i Parry, and Larix l y a l l i i P a r i . , with Vaccinium scoparium Leiberg and Phyllodoce empetriformis (Sw.) D. Don common in the understory. Krummholz forms of these tree species occur at the alpine-subalpine t r a n s i t i o n . Carex scirpoidea Michx. var. pseudosc irpoidea (Rydb.) Cronq., i s the most ubiquitous dominant species on dry, well-drained Lakeview Mountain s i t e s , often co-dominanting with Carex capitata L. Vascular species occurring with these dominants include P o t e n t i l l a d i v e r s i f o l i a Lehm., Arenaria obtusiloba (Rydb.) Fern., and Festuca ovina L. Lichen species such as Cetraria islandica (L.) Ach., C. cucullata (Bell.) Ach., C. n i v a l i s (L.) Ach., and Thamnolina vermicular i s (Sw.) Schaer. TABLE I - SELECTED CLIMATIC DATA FOR WEATHER STATIONS IN SOUTHERN BRITISH COLUMBIA (WITHIN THE 1941-1970 PERIOD)* J -A DENOTES JUNE TO AUGUST. STATION TEMPERATURE ( C) AVERAGE FROST PRECIPITATION (CM) YEARS OF MEAN DAILY MIN. MEAN DAILY MEAN DAILY MAX. FREE PERIOD MEAN TOTAL MEAN RAIN RTAN SNOW RECORD ANN. J -A ANN. J -A ANN. J -A (DAYS) ANN. J - A ANN. J -A ANN. J -A HEDLEY 49\u00C2\u00B021 'N 120\u00C2\u00B005'W 2 10 8 18 14 26 148 29 10 22 10 75 0 524 m HEDLEY NICKEL PLATE 49\u00C2\u00B020'N 119\u00C2\u00B059'W -3 k 2 11 8 18 48 54 14 21 14 330 10 1769 m OLD GLORY 49\u00C2\u00B0g9'N 117 55'W -5 4 -2 8 1 1 1 20 73 16 18 12 558 44 23 2347 m * B .C. Dept . o f A g r i c u l t u r e , 1974 20 are also prevalent. Communities dominated by Carex scirpoidea have been reported for the North Cascades (Douglas and B l i s s 1977), the Snowy Mountains of central Montana (Bamberg and Major 1968), and for the Sierra Nevada Mountains of C a l i f o r n i a (Major and Bamberg 1963). The existence of Carex capitata as a dominant i s apparently limited to the North Cascades (Douglas and B l i s s 1977), and the St. E l i a s Mounatins, Yukon (Douglas, pe r s. c omm.). Vegetation dominated by Kobresia myosuroides ( V i l l . ) F i o r i i s r e l a t i v e l y frequent on similar dry well-drained s i t e s with early snowmelt, and includes species of lesser abundance such as Carex scirpoidea, Arenaria obtusiloba, Cetraria n i v a l i s , and C. cucu l l a t a. Kobresia myosuroides communities have been reported from the North Cascades (Douglas and B l i s s 1977), the Rocky Mountains (Cox 1933, Marr 1967, Bamberg and Major 1968, Knapik et a l . 1973, Hrapko and La Roi 1978, Komarkova and Webber 1978, B e l l and B l i s s 1979), the Sierra Nevada Mountains (Major and Bamberg 1963), and as far north as the St. E l i a s Mountains of the Yukon and Alaska (Hanson 1951, Douglas 1980). Dry, well-drained habitats are also dominated by Dryas octopetala L., Salix n i v a l i s Hook., or Salix cascadensi s Cockerell. Species occurring with Dryas octopetala include Lupinus l y a l l i i A. Gray, Arenaria obtusiloba, and P o t e n t i l l a d i v e r s i f o l i a . Dryas octopetala occurs as a dominant species over a wide geographical area, and has been reported from the North Cascades (Douglas and B l i s s 1977), the Rocky Mountains of Alberta (Beder 1967, Bryant and Scheinberg 1970, Hrapko and La 21 Roi 1978, Knapik et a_l. 1973), more southern Rocky Mountain regions (Johnson and B i l l i n g s 1962, Holway and Ward 1965, Marr 1967, Bamberg and Major 1968), and northern areas in Alaska and the Yukon (Hanson 1951, Price 1971). Salix n i v a l i s occurs with less abundant species such as Cerastium beeringianum Cham. & Schlecht., P o t e n t i l l a d i v e r s i f o l i a , and Lupinus l y a l l i i . Plant communities dominated by Salix n i v a l i s have been reported from alpine areas in the North Cascades (Douglas and B l i s s 1977), Montana (Bamberg and Major 1968), and Alberta (Knapik et a l . 1973). P o t e n t i l l a d i v e r s i f o l i a i s a major species in vegetation dominated by Salix cascadensis, with Silene acaulis, Carex sc i rpoidea, Dryas octopetala, Cetraria n i v a l i s , C. c u c u l l l a t a , and C. is l a n d i c a also common. This community has been reported from only two areas, the North Cascades of Washington and B r i t i s h Columbia (Douglas and B l i s s 1977), and the Medicine Bow Mountains of Wyoming ( B i l l i n g s and B l i s s 1959). Snowbed sit e s on Lakeview Mountain are dominated by Carex breweri Boott var. paddoensis (Suksd.) Cronq., Carex nigricans Retz., or Antennaria lanata (Hook.) Greene vegetation types. Carex breweri dominates s i t e s which are snowfree by late July and occurs with Sibbaldia procumbens L., Arenaria obtusiloba, Erigeron aureus Greene, and Polytrichum p i l i f e r u m Hedw. This community appears to be r e s t r i c t e d to the North Cascades (Douglas and B l i s s 1977). Vegetation dominated by Antennaria lanata also becomes snowfree by July, with dry conditions occurring by late summer. Other common species include Carex scirpoidea, Carex breweri, Carex nigricans, and Polytrichum 22 juniperinum Hedw. This community also occurs in the subalpine zone of Lakeview Mountain and has been reported from the alpine zone of the North Cascades (Douglas and B l i s s 1977), the Olympics (Bliss 1969), and the Rocky Mountains (Beder 1967, Hrapko and La Roi 1978, Knapik et a l . 1973). Carex nigricans dominates poorly-drained s i t e s where snow per s i s t s u n t i l early to late August. Greater than 90% cover of C. nigricans i s common, with r e l a t i v e l y few species occurring with this dominant, e.g., Salix cascadensis and Ranunculus es c h s c h o l t z i i Schlecht. This community is widespread and has been reported from the alpine and subalpine zones of the Cascade Mountains (Douglas and B l i s s 1977, Meredith 1972), the Olympic Mountains (Bl i s s 1969), Kuramoto and B l i s s 1970), and the Rocky Mountains (Beder 1967, Knapik et a l . 1973, Hrapko and La Roi 1978, Helm 1982). A brief account of vegetation within the study area has been included in a description of Similkameen Valley plant communities (McLean 1970). Nearby Red Mountain, also within Cathedral Park, has been sampled by Douglas and B l i s s (1977), contributing data to their alpine and subalpine zone plant community study of the North Cascade Mountains. The western North Cascades of Washington have been included in a general survey of Oregon and Washington vegetation (Franklin and Dyrness 1973), and alpine vegetation within the i n t e r i o r plateau region of south-central B r i t i s h Columbia has been studied by Eady (1971). The ecology of Larix l y a l l i i (Alpine Larch) within the eastern North Cascades has been considered by Arno and Habeck 23 (1972) . ANIMALS Hoary Marmot (Marmota caligata [Eschscholtz], Columbian Ground Squirrel (Spermophilus columbianus columbianus [Ord]), Mule Deer (Odocoileus hemionus hemionus [Rafinesque3), Pika (Ochontona princeps [Richardson]), C a l i f o r n i a Bighorn Sheep (Ovis canadensis c a l i f o r n i a n a Douglas), White-tailed Ptarmigan (Lagopus leucurus), and Mountain Goat (Oreamnus americanus [ B l a i n v i l i e ] ) have been observed grazing alpine vegetation within the study area. Other herbivorous mammals l i v i n g within or ranging into the alpine zone of Cathedral Park include Northwestern Chipmunk (Eutamias amoenus [A l l e n ] ) , Cascade Mantled Groundsquirrel (Spermophilus saturatus [Rhoads]), Deer Mouse (Peromyscus maniculatus [Wagner]), Vole (Microtus sp.), and Snowshow Hare (Lepus amer icanus Erxleben). Carnivores such as Lynx (Lynx canadensis Kerr), Black Bear (Ursus americanus P a l l a s ) , Coyote (Canis latrans Say), and Weasel (Mustela sp.) range in to the alpine zone (Chess Lyons unpubl.) 24 II I . METHODS VEGETATION Transect Placement The study s i t e i s located in the high alpine zone of Lakeview Mountain (Fig. 1). Six 2 m X 30 m belt transects were established at thi s s i t e - chosen to include the most common dominant species present, as well as a range of aspects, for comparative purposes (Table II, F i g . 2). Transects were positioned immediately following snow release in June, 1980, using the remains of the previous years vegetation as the primary placement c r i t e r i o n . Each transect was placed in an Table II - Transect Characteristics TRAN. ASPECT SLOPE ELEV. DOMINANT SPECIES A N58\u00C2\u00B0W 9% 2450 _ Carex scirpoidea & C. capitata 2447 m B S80\u00C2\u00B0W 1 3% 2438 2434 m C. scirpoidea & C. capitata C N29\u00C2\u00B0E 16% 2444 2439 m C. scirpoidea & C. capitata D S2\u00C2\u00B0E 14% 2405 2401 m C. scirpoidea & Kobresia myosuroides E N1 6\u00C2\u00B0W 1 0% 2426 2423 m C. scirpoidea & K. myosuroides F S56\u00C2\u00B0E 7% 2475 2473 m C. scirpoidea & K. myosuroides 25 Figure 2 - Position of Transects (A-F) in the Study S i t e . 26 attempt to include two areas dominated by d i f f e r e n t species and separated by a t r a n s i t i o n zone. Transects were 2 m wide as vegetation homogeneity tended to decrease with greater width and only one d i r e c t i o n of major variation ( v e r t i c a l or downslope) was desired. Downslope v a r i a t i o n was required to allow for future ease in i d e n t i f i c a t i o n of community types and t r a n s i t i o n zones, as well as for subsequent grouping of horizontal point-l i n e data corresponding to these communities. Point-line sampling and association analysis are described in later methods sections. Transects were limited to 30 m in length so that a variety of aspects and vegetation types could be sampled within p r e v a i l i n g time constraints. Quadrat Sampling Design At 1 m intervals along the length of each transect, a 2m sampling row was established across the transect. Along each row, three 20 X 50 cm quadrats were randomly selected (using random number tables) from a possible 10 and placed perpendicular to the slope contours (Fig. 3). Each quadrat was divided into 20 sections, each 5 X 1 0 cm, aiding in the v i s u a l estimation of crown cover to the nearest 5% (less than 5% = T [trace]) for each species. Crown cover i s the percentage of ground covered by a v e r t i c a l projection of the shoots of a plant species; i n t r a s p e c i f i c overlap i s ignored. A t o t a l of 90 quadrats were sampled per transect, giving a sampling intensity of 15% for percentage cover within each belt transect. Sample sizes of 6.2% (Bliss 1963) and 4% (Douglas and B l i s s 1977) have 27 F i g u r e 3 - Q u a d r a t S a m p l i n g D e s i gn 2 m 30 m 1 m SOIL PIT 1 m 0 \u00C2\u00A9 TEMPERATURE DIODES ROWS OF EQUIDISTANT POINTS (EVERY 2cm) QUADRATS (20 X 50cm) 28 been found to adequately describe similar vegetation and have s a t i s f i e d the minimal area c r i t e r i o n of Cain (1938). The 20 X 50 cm quadrat i s well suited to the small stature of herbaceous alpine species ( B l i s s 1963) and allows r e l a t i v e l y accurate v i s u a l cover estimates (Daubenmire 1968). Elongate or rectangular quadrats have been found to be the most e f f i c i e n t (fewer quadrats needed to obtain a representative sample) when orientated p a r a l l e l to the d i r e c t i o n of greatest change or variance in the sampling area (Clapham 1932, Bormann 1953). A greater number of d i f f e r e n t species are l i k e l y to be included in each quadrat with t h i s shape and placement (Kershaw 1973). Analyses Of Quadrat Data The multivariate techniques of ordination and cluster analysis were used with percentage cover data to a i d in the d e f i n i t i o n of community types within each transect. This was necessary to assess the variation of communities with aspect. As well, relationships between climate, s o i l s , and phenological data, and d i f f e r e n t communities or d i f f e r e n t stands of the same community could be determined. Division of transects was also needed so that small scale vegetation data (point-lines) recorded within transects could be grouped and analyzed separately, according to the community type in which they were col l e c t e d . This was done for comparative purposes. Also, a degree of vegetation homogeneity i s necessary to s a t i s f y s t a t i s t i c a l assumptions of the po i n t - l i n e or association analysis. The i d e n t i f i c a t i o n of community types must be made 29 with p r a c t i c a l considerations in mind, however, as too many units have limited comparative and general information value. In addition to separate multivariate analyses for each transect, data from a l l transects were combined for further analyses. This was done to a i d f l o r i s t i c and abundance data comparisons between d i f f e r e n t stands of each community, as well as for an o v e r a l l comparison of sampled communities within the study area. Cluster analysis i s a c l a s s i f i c a t i o n or data reduction technique used to separate data into homogenous groups (Everitt 1974), although groupings can often be arb i t r a r y where communities intergrade continuously (Goodall 1978b, Whittaker 1978). Ordination i s also a tool for data reduction, but i s generally used to depict the range of v a r i a t i o n in a data set rather than d i s c o n t i n u i t i e s . The two approaches of c l a s s i f i c a t i o n and ordination are, in theory, very, d i f f e r e n t , but may show similar trends in practice (Greig-Smith 1964) and can act to supplement and evaluate each other (Pritchard and Anderson 1971, Whittaker and Gauch 1978). Discontinuities in a data set w i l l be revealed as clu s t e r s in an ordination, often more c l e a r l y than with conventional c l u s t e r i n g procedures (Williams et a l . 1969, Goodall 1978b). Quadrats with 50% or more rock were deleted from each data matrix before any multivariate techniques or data transformations were applied. This was done to minimize the d i s t o r t i o n produced by extreme sample o u t l i e r s , p a r t i c u l a r l y evident with ordination methods (Gauch et a l . 1977). In 30 addition, species present in less than 5 quadrats were removed before ordination and c l u s t e r i n g . Such species tend to encode l i t t l e ecological information (Gauch 1977) and often d i s t o r t r e s u l t s , p a r t i c u l a r l y since centering and standardization techniques give equal weight to a l l species (Goodall 1978a, Whittaker and Gauch 1978, Pimentel 1979). Transect quadrat data were grouped and averaged for each sampling row (Fig. 2), producing composite samples (from three o r i g i n a l quadrats where rock was less than 50%). This resulted in t h i r t y composite samples or strata per transect, which were then used for ordination and c l u s t e r i n g . Grouping of samples can often c l a r i f y results by reducing the effects of sample error and chance differences in species abundances (Gauch 1973a, Gauch and Whittaker 1981). In addition, a large data set i s unwieldy when using two-dimensional scatter plots and cluster dendrograms. Multivariate ordination techniques used were centered p r i n c i p a l components analysis (PCA), centered and standardized (PCA) (Orloci 1966, G i t t i n s 1969), and reciprocal averaging (RA) - a term f i r s t used by H i l l (1973), although Hirschfeld (1935) proposed the o r i g i n a l algorithm. Data were analyzed by these ordination methods using the Ordiflex computer program package (Gauch 1977). This was used in conjunction with p l o t t i n g programs (Wong unpubl.) which provided scatter diagrams showing sample numbers. The indirect ordination methods used have been previously reviewed by Gauch and Whittaker (1972), Beals (1973), and Gauch et a l . (1977). P r i n c i p a l components analysis (PCA) i s limited 31 to r e l a t i v e l y homogenous samples as i t assumes a linear relationship amoung variables (Austin and Noy-Meir 1971, Orloci 1978) . Centered PCA subtracts the mean value for each species from the o r i g i n a l values before eigenanalysis. The contribution of each species i s therefore proportional to i t s variance and, as t h i s tends to increase with mean, abundant species are often stressed (Noy-Meir e_t a l . 1975, Pimentel 1979). Centered and standardized PCA standardizes species to unit variance, equalizing species contributions. This tends to emphasize rare and absent common species, rather than abundant ones (Goodall 1978a, Pimentel 1979). The variance accounted for by each axis i s t y p i c a l l y reduced by centering and standardizing (Austin and Greig-Smith 1968). Involution of axes i s more common with non-standardized data (Austin and Noy-Meir 1971), as are d i s t o r t i o n due to sample c l u s t e r s , and point scatter due to noise (Gauch et' a l . 1977). When species abundances are important c r i t e r i a , however, data standardization often gives poor re s u l t s , as the single presence of a species receives a large score (Pimentel 1979) . Reciprocal averaging (RA) i s useful when r e l a t i v e l y high sample heterogeneity i s present, with the resulting sample clusters producing less d i s t o r t i o n than with PCA. A curvature of sample positions i s produced by the second axis, however, and the ordination of outlying samples near the periphery of the scatter plot may cause compression of remaining samples in the opposite d i r e c t i o n (Gauch et_ a l . 1 977). In addition, the simultaneous double standardization of species and samples employed by RA tends to emphasize rare species and unique s i t e s 32 (Pimentel 1979). RA i s more suited to the non-linearity of ecological data than i s PCA, however, with the f i r s t axis producing more accurate sample placement with- less d i s t o r t i o n (Whittaker and Gauch 1978). The application of a variety of multivariate techniques to each data set i s advisable for comparative purposes. An agglomerative h i e r a r c h i a l c l u s t e r i n g method was employed using the MIDAS s t a t i s t i c a l package (Fox and Guire 1976). Ward's method of minimum variance was used with a Euclidean distance measure. Cophenetic c o r r e l a t i o n was calculated for each clu s t e r analysis. This measure of \"best f i t \" was developed by Sokal and Rohlf (1962) and relates o r i g i n a l distances (from the secondary distance matrix) to distances (cophenetic values) indicated by the cluster dendrogram. This product-moment cor r e l a t i o n c o e f f i c i e n t tends to vary between 0.6 and 0.95 depending on the c l u s t e r i n g technique and data structure, with high values implying that the dendrogram i s a reasonable i l l u s t r a t i o n of sample a f f i n i t i e s based on species d i s t r i b u t i o n s and abundances (Sneath and Sokal 1973). Clustering techniques have been reviewed by Sneath and Sokal (1973) and E v e r i t t (1974), and the application of these methods occurs frequently within the l i t e r a t u r e . Clustering methods w i l l tend to find groupings within a data set, regardless of the structure (Orloci 1975, Gauch and Whittaker 1981) and the comparison of c l u s t e r i n g results with those from ordination i s advised as groupings are not so r i g i d l y defined in the l a t t e r . Recognition of sample groups can be f a c i l i t a t e d i f 33 the dendrogram i s examined for large changes between fusions (Everitt 1974). Ward's method of minimum variance maximizes the variance between classes and minimizes that between them at each computational step, an optimal feature in a c l a s s i f i c a t i o n technique (Goodall 1978). Although groups or differences tend to be greatly emphasized with t h i s method (Everitt 1974), consistently useful and interpretable results are found (Pritchard and Anderson 1971). This algorithm gives results that are consistent with an analysis of Euclidean distances between samples in a data set (Orloci 1975). Point-line Sampling A p l o t l e s s l i n e sampling system described by Pielou (1967) and Stowe and Wade (1979) was used to detect the presence or absence of small scale associations between plant species. Quadrats are generally not suitable to test for t h i s scale of association, as results w i l l depend on the size of quadrat used. With r e l a t i v e l y large quadrats, for example, s p a t i a l l y separated species appear p o s i t i v e l y associated, and, as quadrats approach the size of individual plants, associations become negative due to species exclusions (Greig-Smith 1964). Plotless techniques, using points rather than quadrats, therefore are more appropriate. Three 2 m long lines of equidistant points (every 2 cm) were placed 15 cm apart at each 1 m i n t e r v a l along each transect (Fig. 3). A fourth l i n e was placed within t h i s area i f >25% of 34 any of the three lines contacted rock. The species occurring nearest to each sampling point, but within a radius of 1 cm from this point, was recorded. Any portion of the shoot constituted an occurrence and mosses.and lichens were also recorded. If no species occurred within 1 cm, then a blank was recorded and and treated as a species in the subsequent analysis. Vegetation of low stature, such as grassland, alpine, and bryophyte communities, are best suited to this sampling method, especially i f there are extensive bare patches within the vegetation. Approximately 9000 points were sampled per transect. The 2 cm int e r v a l was chosen because the average diameter of most of the vascular plant species present was estimated to be s l i g h t l y greater than t h i s . Each successive point at thi s scale was found to contact either the same individual plant contacted previously or the closest d i f f e r e n t i n d i v i d u a l . There are no s t a t i s t i c a l l i m i t s on the choice of a distance between points, however, i f the distance i s too small, i n e f f i c i e n t sampling may resu l t , with many blanks recorded or the same individual plant recorded many times. If the distance i s too large, the species recorded w i l l not necessarily be adjacent. Analysis Of Point-line Data Lines of point data were grouped within each 2 m X 30 m transect according to the vegetation types.and t r a n s i t i o n zones suggested by multivariate analysis of quadrat data. Homogeneity of grouped l i n e s is required to s a t i s f y the s t a t i s t i c a l assumptions of thi s analysis. The t r a n s i t i o n from the la s t 35 species of one l i n e to the f i r s t species of the next i s necessarily ignored during analysis. The chains of species occurrences were collapsed so that sequential occurrences of the same species became a single record. This process l i m i t s the results to i n t e r s p e c i f i c associations only. At the present time, no adequate method exists to sample for i n t r a s p e c i f i c associations, primarily because of the extreme d i f f i c u l t y in determining individuals, p a r t i c u l a r l y in species with extensive vegetative growth. The algorithm for analysis of p o i n t - l i n e data was o r i g i n a l l y proposed by Pielou (1967), and was subsequently used by Stowe and Wade (1979), where i t was termed the species juxtapositions method. A species juxtaposition i s , simply, the side by side occurrence of two d i f f e r e n t species, or a t r a n s i t i o n between them. This algorithm has since been restructured by de Jong and Greig (1983), because Pielou's (1967) method i s not correct for a l l possible cases. As well, the model of randomness i s d i f f i c u l t to interpret, and the tests for randomness are less than rigorous and do not allow for the e s s e n t i a l l y d i r e c t i o n l e s s nature of p o i n t - l i n e data. The new algorithm (de Jong and Greig 1983) i s based on a f i r s t order Markov chain model, as i s Pielou's (1967) method. The sequence of species in a Markov chain i s random - the t r a n s i t i o n from one species (e.g., 'A') to any d i f f e r e n t species has the same pro b a b i l i t y , provided the species are present in equal proportions. Successive observations are dependent only in that the t r a n s i t i o n from 'A' must be to a species other than 'A' - no 36 two adjacent species are the same in a Markov sequence. The Markov sequence becomes the expected values for the analysis, with p r o b a b i l i t i e s dependent on the r e l a t i v e abundance of each species in the data matrix. For example, two common species are expected to follow each other more often than would two rare species. The actual c a l c u l a t i o n of expected values begins with the number of times each species is involved in a t r a n s i t i o n and uses an i t e r a t i v e procedure (de Jong and Greig 1983) to arrive at the expected number of transitions between each species-pair. As the analysis i s less accurate when very low observed values are present, rare species (recorded less than 6 times in the data set) were grouped into a miscellaneous category before the ca l c u l a t i o n of expected values. This cut-off point was suggested by Pielou (1967). The matrix of expected values is then compared to the observed t r a n s i t i o n frequencies in a goodness of f i t or chi-square test. S i g n i f i c a n t l y large c h i -square values (p<0.05) indicate departures from the Markov model, and, therefore, s i g n i f i c a n t non-random structure within the data set. This analysis d i f f e r s from that proposed by Pielou (1967) in that symmetrically opposed elements in both matrices (observed and expected) are combined (the matrix i s folded) before the chi-square analysis. This removes the d i r e c t i o n a l aspect of the data. For example, t r a n s i t i o n s from species 'A' to species 'B' are grouped with transitions from 'B' to 'A', as no b i o l o g i c a l d i s t i n c t i o n can be made between the two. The analysis proposed by Pielou (1967) determined non-37 randomness of the entire data set only. Stowe and Wade (1979) extended the analysis of s i g n i f i c a n t l y non-random data sets with the application of a matrix-residual, to test for deviations from randomness for each species-pair. The appropriate standardized residual for folded matrices i s given by de Jong and Greig (1983). This s t a t i s t i c i s normally d i s t r i b u t e d and may be compared to the standard normal table to determine i f s i g n i f i c a n t (p<0.05) differences exist between observed and expected values for each species-pair. A positive residual value indicates p o s i t i v e association between two species, and a negative residual value indicates negative association. Positive and negative associations mean that two species tend to occur together more often, or less often, respectively, than would be expected i f their d i s t r i b u t i o n were random. Species with both observed and expected values of less than 5 i n t e r s p e c i f i c t r a n s i t i o n s were not considered in the presentation and interpretation of re s u l t s , so as to eliminate s i g n i f i c a n t associations with no b i o l o g i c a l or p r a c t i c a l meaning. For example, a spurious, though highly s i g n i f i c a n t , p o s i t i v e association would be detected between two species with an observed value of 1 and and expected value of 0.0001. This p l o t l e s s p o i n t - l i n e or species juxtapositions method is a l l i e d to the contact sampling method developed by Yarranton (1966) for bryophyte/lichen communities and subsequently used in pastures (Turkington et a l . 1977, Aarssen et a l . 1979, Turkington and Harper I979a,b, Aarssen 1983). The method of c a l c u l a t i n g the chi-square s t a t i s t i c i s these studies was 38 modified by de Jong et a l . (1983). Coincidentally, the analysis and methods of calc u l a t i o n used in th i s thesis (de Jong and Greig 1983) are very similar to the method proposed by de Jong et a l . (1983), although both the method of data c o l l e c t i o n , models for randomness, and subsequent interpretation are d i f f e r e n t . Yarranton's (1966) method was not used in t h i s study because i t depends on a r e l a t i v e l y continuous ground cover - a c r i t e r i o n not often met in alpine areas, due to extensive patterned ground (e.g., stone c i r c l e s , rock r i v e r s , frost b o i l s , etc.) Phenology Phenological data were recorded during the 1980 growing season for vascular plant species at a l l transect s i t e s . Plots (2 m X 2 m) were established in each subjectively determined vegetation type in June, 1980. When a l l transects were completely snowfree (June 18, 1980), the times of vegetative growth, flowering, f r u i t i n g , seed dis p e r s a l , and dormancy stages were recorded at weekly intervals u n t i l September 4, 1980. At thi s point, a l l species were in late f r u i t i n g , seed dis p e r s a l , or dormancy stages. Stages were recorded when at least 50% of a species population (estimated v i s u a l l y ) had reached that point. 39 Nomenclature Nomenclature and taxonomy follows, with some exceptions, Hitchcock and Cronquist (1973) for vascular plants, Lawton (1971) for mosses, and Hale and Culberson (1970) for lichens. The use of Lupinus l y a l l i i A. Gray follows Dunn and G i l l e t t (1966), Oxytropis monticola Gray ssp. monticola follows Elisens and Packer (1980), and Draba cana Rydberg follows Mulligan (1971). Thamnolina vermicular is (Sw.) Schaer. has been included with T. subuliformis (Ehrh.) W. Culb. as they are not distinguishable in the f i e l d , requiring chemical tests for positive i d e n t i f i c a t i o n . In the text, only the binomial i s used, omitting the variety or subspecies, i f the species has only one variant in the study area. Voucher specimens have been deposited in the herbarium of the University of B r i t i s h Columbia. SOILS S o i l p i t s were established in June 1980 within each subjectively determined vegetation type in each transect. A and B horizons were described in each p r o f i l e to minimum depths of 30 cm. Composite samples were c o l l e c t e d from both A and B horizons and laboratory analysis conducted on the fine (<2 mm) f r a c t i o n (Table I I I ) . S o i l color was described using Munsell color charts with moist and dry s o i l in natural l i g h t . 40 Table III - Methodology for Physical and Chemical S o i l Analyses ANALYSIS METHOD OR TECHNIQUE REFERENCE Texture Hydrometer Method Bouyoucous (1951) pH pH Meter-Glass Electrode Type 29b Bates (1954) Total Carbon & % Organic Matter Leco Induction Furnace (Model 521) and Leco Carbon Analyzer (572-200) Described in Black (1965) Total Cation Exchange Ammonium Acetate Method (pH 7.0)-Technicon Autoanalyzer II (NH4+-N) Schollenberger and Simon (1945) Exchangeable Cations (K, Ca, Mg) Ammonium Acetate Method (pH 7.0)-Perkin-Elmer Atomic Absorption Spectrophotometer (KC1 extraction) Schollenberger and Simon (1945) Total Nitrogen Macrokjeldahl Method - A c i d Digestion. Colorimetric Analysis -Technicon Autoanalyzer II Kjeldahl (1883), Bremner (1960) Available Phosphorus NH4F in HC1 Extraction Colorimetric Determination with Spectrophotometer Bray and Kurtz (1945) 41 CLIMATE The climate of Lakeview Mountain in summer (1980) was monitored at three stations with aspects and elevations corresponding to Transects B, C, and D. Temperature and atmospheric moisture were recorded with Schreibstreifen R. Fuess hygrothermographs placed in white Steveson screens (louvered boxes) with double tops, allowing a i r to c i r c u l a t e , and minimizing surface heating. Sensors were between 18 and 25 cm above the ground. P r e c i p i t a t i o n was co l l e c t e d with a Tru-check raingauge set 60 cm above the ground surface. Windspeed was measured with Belfort 3-cup t o t a l i z i n g anemometers set 60 cm above the ground. Station 1 was located S84\u00C2\u00B0W at 2481 m, above Transect B, with a hygrothermograph, anemometer, and raingauge. Station 2 was located S2\u00C2\u00B0E at 2402 m, below Transect E, with a hygrothermograph and anemometer. Station 3 was situated above Transect C at an aspect of N29\u00C2\u00B0E and an elevation of 2475 m, with a hygrothermograph only. Microclimate was recorded at each s o i l p i t s i t e in each transect (a t o t a l of 14 sites) at weekly intervals during the summer of 1980. S o i l temperatures were measured with laboratory ca l i b r a t e d Varah FD 300 diodes sealed with s i l i c o n . Diodes were placed at depths of 2, 10, and 20 cm below the surface in r e l a t i v e l y undisturbed s o i l approximately 10 cm from the p i t edge (Fig. 2). Resistances were measured with a battery powered 6.75 V bridge-meter. Air temperature and humidity were monitored with a battery powered fan psychrometer at heights of 2, 10, and 20 cm above ground. S o i l moisture was determined for 42 June 25 - July 1, 1980, and September 6 - 7 , 1980 by gravimetric samples taken at depths of 5-10 cm and 20-30 cm at each p i t s i t e . Percent water was obtained after drying s o i l s at 110\u00C2\u00B0 C for 24 hours. 43 IV. RESULTS VEGETATION Community Types 1. Transect A; A l l data from the 90 quadrats in transect A were used to form t h i r t y composite samples or strata (Appendix C). The 13 species having less than 5 occurrences in these composite samples were removed, leaving 43 species (variables) for analysis. The data matrix i s characterized by f a i r l y consistent high cover values for Carex sc irpoidea (mean 28%), Carex capitata (mean 28%), and Cetraria i s l a n d i c a (mean 24%), with P o t e n t i l l a d i v e r s i f o l i a and Cetraria n i v a l i s both averaging 15% (Appendix C). Total species cover in samples ranged from 170-293% (mean 220%), with the highest t o t a l cover found in samples 20-30 (262%). Multivariate Analyses: Analysis by centered p r i n c i p a l components analysis (PCA), centered and standardized PCA, and reciprocal averaging (RA) (Fig. 4), accounted for 47%, 29%, and 35% of sample variation in the f i r s t two axes, respectively. Axis 3 accounts for only a small amount of additional variance. A l l three analyses and axes combinations indicate l i t t l e structure within t h i s data set. Samples 20-30, however, i l l u s t r a t e a f f i n i t y (possibly due to the presence of Carex nardina), as do anomalous samples 1 and 17-19 which contain less than 12% Carex capitata. Samples 6 and 44 F i g u r e 4 - T r a n s e c t A M u l t i v a r i a t e A n a l y s e s CENTERED PRINCIPAL COMPONENTS ANALYSIS CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS . 5 . 13 U 15 . 1 6 \u00E2\u0080\u00A220 .11 . 18 . 1 9 . 1 7 \u00E2\u0080\u00A2 21 23* 2 6 * ,5 *9 . 1 * *7 \u00E2\u0080\u00A2 2 7 . 6 RECIPROCAL AVERAGING 9 2 . . 5 * 20 28 % . -22 29 MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE f*\ \C S >J\ \D O \u00E2\u0080\u0094 rsj u** t\u00C2\u00A3 _^r*\u00C2\u00BB CT* CO O 45 10 o c c u r at a l a r g e d i s t a n c e from o t h e r sample p o i n t s i n the RA s c a t t e r p l o t - b oth have a h i g h (30%) c o v e r of P o l y t r i c h u m p i l i f e r u m , which averages 2% i n the r e m a i n i n g samples. \u00E2\u0080\u00A2 A c l u s t e r a n a l y s i s u s i n g minimum v a r i a n c e or Ward's Method i n c o n j u n c t i o n w i t h E u c l i d e a n d i s t a n c e i s i l l u s t r a t e d i n F i g . 3. D i s t a n c e s drawn between f u s i o n s i n t h i s and subsequent c l u s t e r dendrograms a r e p r o p o r t i o n a l t o the a c t u a l E u c l i d e a n d i s t a n c e s . The c l u s t e r of samples 20-30 o c c u r s a t a r e l a t i v e l y l a r g e d i s t a n c e from the f i n a l f u s i o n of a l l samples i n F i g . 3. C l u s t e r s w i t h i n the r e m a i n i n g samples a r e l e s s d i s t i n c t . C o p h e n e t i c c o r r e l a t i o n r e l a t e s o r i g i n a l E u c l i d e a n d i s t a n c e s t o t hose r e s u l t i n g from dendrogram c o n s t r u c t i o n , where d i s t a n c e s are r e c a l c u l a t e d a t each s t e p . The v a l u e f o r t h i s c l u s t e r a n a l y s i s i s r e l a t i v e l y low a t .4966. H i g h v a l u e s ( e . g . , >.6) imply t h a t the dendrogram i s a r e a s o n a b l e i l l u s t r a t i o n of sample a f f i n i t i e s . V e g e t a t i o n \"Groups: L i t t l e s t r u c t u r e i s apparent i n t h i s d a t a s e t , a l t h o u g h the c o v e r of dominant s p e c i e s v a r i e s c o n s i d e r a b l y i n some samples. A n a l y s e s i n d i c a t e , however, t h a t t h i s v a r i a b i l i t y does not w a r r e n t d a t a s e t d i v i s i o n . The e n t i r e d a t a s e t i s c l a s s e d as one community t y p e , dominated by Carex c a p i t a t a and Carex s c i r p o i d e a . Thus, p o i n t - l i n e d a t a f o r t h i s t r a n s e c t w i l l not be s u b - d i v i d e d b e f o r e a s s o c i a t i o n a n a l y s i s . 46 2. Transect B: Thirty composite samples, formed from a t o t a l of 90 o r i g i n a l quadrats, (Appendix C) were used for multivariate analysis. Thirty-nine species were used after the 6 species with less than 5 occurrences in these samples were removed. The data matrix i s characterized by uniformly high cover values for both Carex scirpoidea (mean 26%) and Carex capitata (mean 40%) (Appendix C). Cetraria i s l a n d i c a averages 22% cover, and Cetraria n i v a l i s , 10%. Multivariate Analyses: Analysis by centered PCA, centered and standardized PCA, and RA (Fig. 5), accounted for 48%, 34%, and 37% of sample var i a t i o n in the f i r s t two axes, respectively. Sample points form no d i s t i n c t groups with the f i r s t three axes of these ordinations. Sample 1 occupies an outlying position, possibly due to the absence of Cetraria cucullata, a low value for P o t e n t i l l a d i v e r s i f o l i a (9%), and r e l a t i v e l y high cover of Cladonia sp. (18%). RA produced a number of o u t l i e r s , which include samples 6, 8, and 23, perhaps due to their r e l a t i v e l y high cover values for Silene ac a u l i s. The dendrogram resulting from cluster analysis (Fig. 5) shows a small cluster of samples 14 and 22-27 a r e l a t i v e l y large distance from the f i n a l fusion. The remaining samples fuse close to this f i n a l linkage. The cophenetic c o r r e l a t i o n is low at .5010, implying that some d i s t o r t i o n of sample a f f i n i t i e s has occurred during dendrogram construction. 47 F i g u r e 5 - Transect B M u l t i v a r i a t e Analyses CENTERED PRINCIPAL COMPONENTS ANALYSIS CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS *27 21 ' 1 . 1 6 3 28 \"2 13 * 2 0 \u00E2\u0080\u00A2 1 8 29* 17 I f ' 9 * 2} 2t \u00E2\u0080\u00A2 2 5 26 18 \u00E2\u0080\u00A2 2 , \u00C2\u00AB \u00E2\u0080\u00A2 30 1 4 . RECIPROCAL AVERAGING MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE . 6 2 9 . 30 . II 19 * * \u00C2\u00BB 15 21 \u00C2\u00AB26 28 13 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 20 27 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2\u00C2\u00AB 12 \u00E2\u0080\u00A2 3 : m n r n I r ^ n [ i i i ^ ^ tt \u00E2\u0080\u0094 c^< r n - y r * \u00E2\u0080\u0094 O \u00E2\u0080\u0094 CO O \"\ \u00E2\u0080\u00A2\u00E2\u0080\u00A2D U~\ o J \ CTNtnrv. \o 49% rock were omitted. Forty-four species were used for multivariate analysis, after the removal of 4 infrequent species (<5 occurrences). High cover values for both Carex scirpoidea (range 8-45%; mean 26%) and Carex capitata (range 5-60%; mean 30%) dominate th i s data matrix. A distinguishing feature i s the presence of Salix n i v a l i s in 12 composite samples (2-8, 13-15, and 21-22), with percentage cover ranging from 8-48%, with a mean of 25%. On average, these samples are also characterized by low cover values for both Carex scirpoidea and Carex capitata, which range at higher values of 22-60% and 20-53%, respectively, in the remaining samples. 49 Multivariate Analyses: The application of a centered PCA, a centered and standardized PCA, and RA (Fig. 6), resulted in 64%, 29%, and 46% of sample variation explained by the f i r s t two axes, respectively. The a f f i n i t y of samples 2-8, 13, 14, and 21-22 (containing Salix n i v a l i s ) , i s i l l u s t r a t e d with axes 1 and 2. Sample 14 (a lower amount of Salix n i v a l i s ) is often positioned midway between this group and the remaining samples. Sample 15 (containing 13% Salix n i v a l i s ) occurs closest to the samples dominated solely by Carex capitata and Carex sc i rpoidea, possibly due to i t s 47% cover of Carex capitata. The presence of Penstemon procerus in samples 11, 16, 20, and 25 (25% in sample 25), l i k e l y accounts for their outlying positions in the RA scatter p l o t . Scatter plots of the f i r s t and t h i r d axes were very similar to t h i s , although sample a f f i n i t i e s were not i l l u s t r a t e d with axes 2 and 3 - possibly due to the small amount of v a r i a t i o n accounted for. Cluster analysis produced two major clusters fusing a large distance from the f i n a l cluster of a l l samples (Fig. 6). Samples containing Salix n i v a l i s (2-8, 13-14, and 21-22) form one of these d i s t i n c t groups, with sample 15 included with the remaining data points. The cophenetic c o r r e l a t i o n i s .6330, implying that the dendrogram i s a reasonable i l l u s t r a t i o n of sample a f f i n i t i e s . Vegetation Groups: On the basis of these analyses, i t i s proposed that transect C be grouped as follows: 50 Figure 6 - Transect C Multivariate Analyses CENTERED PRINCIPAL COMPONENTS ANALYSIS CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS 18 \u00E2\u0080\u00A2 i 19 . 2 5 16 . 2 7 \u00C2\u00AB . 2 3 . 2 6 . 2 . 2 9 . 1 3 22 * . 2 3 . . ' 9 3 * 18 ^ \u00E2\u0080\u00A2 27 . 2 0 26 *10 RECIPROCAL AVERAGING MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE 2 3 1 5 2 9 \" .V . 3 0 2 7 io* \u00E2\u0080\u00A2 3 6 * - 7 \u00E2\u0080\u00A2 \u00C2\u00BB \u00E2\u0080\u00A2 20 51 1) Samples 2-8, 13, 14, and 21-22, characterized by medium to high cover (mean 26%) of Salix n i v a l i s , with correspondingly lower values for Carex scirpoidea and Carex capitata. 2) Samples 1, 9-12, 15-20, and 23-30, characterized by r e l a t i v e l y high cover (>17%) of both Carex scirpoidea and Carex capitata. Point-line data w i l l therefore be analyzed for associations separately within these groups. 4. Transect D: A composite data matrix of 30 samples (Appendix C) was formed from 74 of the o r i g i n a l quadrats; as sixteen quadrats with >50% rock were removed. Forty-three species were used for analysis, after the 6 species having less than 5 occurrences were deleted. The transect i s characterized by a high proportion of both rock (3-45%; mean 12%), and bare or disturbed ground (5-30%; mean 8%), in the quadrats used for analysis. Cover values' for vascular plants and cryptogams are r e l a t i v e l y low as a r e s u l t , with t o t a l cover of species in composite samples ranging from 110-130%, compared to an average t o t a l plant cover of 220% in Transect A samples. Carex scirpoidea occurred in a l l samples with a range of 5-25% cover (mean 17%), as did Arenaria obtusiloba (mean 12%), and P o t e n t i l l a d i v e r s i f o l i a (mean 8%). The lichens, Cetraria n i v a l i s and Cetraria i s l a n d i c a , occurred in a l l samples with average cover of 5% and 4%, respectively. 52 Multivariate Analyses: Analysis by centered PCA, centered and standardized PCA, and RA, a l l i l l u s t r a t e two major groups in th i s data set with axes 1 and 2 (Fig. 7) and with axes 1 and 3, with a smaller, intermediate group apparent with centered PCA and RA. Axes 2 and 3 do not i l l u s t r a t e these groups, however, possibly because of the small amount of t o t a l variation they explain. The f i r s t two axes of each ordination account for 65%, 26%, and 36% of sample v a r i a t i o n , respectively. Samples 9, 20-21, 23, and 26-29 form a group characterized by high values for Kobresia myosuroides (25-38%) and correspondingly low values for Carex scirpoidea (7-12%; mean 8%). Samples 1-7, 11-18, and 25 form a second group dominated by Carex scirpoidea (13-30%; mean 21%), with v i r t u a l l y no Kobresia myosuroides present. The remaining samples contain intermediate values for both Carex scirpoidea (mean 15%), and Kobresia myosuroides (mean 13%), a group which includes sample 23 (\"high Kobresia\") in the centered and standardized PCA and RA scatter p l o t s . Sample 7 i s outlying in the RA scatter diagram, possibly due to the r e l a t i v e l y high cover of Carex nardina\u00E2\u0080\u00A2 The cluster analysis dendrogram groups \"high Kobresia myosuroides\" samples in a d i s t i n c t cluster a large distance from the f i n a l fusion. The cluster of remaining samples has two major d i v i s i o n s which separate samples with intermediate values for Carex scirpoidea and Kobresia myosuroides (8, 10, 19, 22, 24, and 30) from samples dominated solely by Carex scirpoidea. The cophenetic c o r r e l a t i o n i s .8144, implying that the 53 F i g u r e 7 - T r a n s e c t D M u l t i v a r i a t e A n a l y s e s CENTERED PRINCIPAL COMPONENTS ANALYSIS *23 \u00E2\u0080\u00A2 1 7 . 12 2 7 * \u00E2\u0080\u00A2 , \u00E2\u0080\u009E 2 / CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS \"28 \u00E2\u0080\u00A2 16 \u00E2\u0080\u00A2 1 7 L5 . 1 3 5 . \u00E2\u0080\u00A2 * 3 ' . . 10 RECIPROCAL AVERAGING MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE \u00E2\u0080\u00A2 9 \u00E2\u0080\u00A2 2 9 \u00E2\u0080\u00A2 2 * \u00E2\u0080\u00A2 2 3 \u00E2\u0080\u00A2 1 9 \u00E2\u0080\u00A2 1 5 18 co j - p-j o o en o \u00E2\u0080\u00A2 54 dendrogram is a good i l l u s t r a t i o n of sample a f f i n i t e s . Vegetation Groups: Sample groupings for Transect D are as follows: 1) Samples 9, 20, 21, 23, and 26-29, dominated by Kobresia myosuroides. 2) Samples 8, 10, 19, 22, 24, and 30, characterized by intermediate values for both Kobresia myosuroides and Carex scirpoidea, and appearing to form a \" t r a n s i t i o n zone\" to either side of samples containing extremely high cover values for Kobresia myosuroides (Appendix C). 3) Samples 1-7, 11-18, and 25, dominated by Carex scirpoidea. Point-line data w i l l be sub-divided into these three groups before association analysis. 5. Transect E: Eighty o r i g i n a l quadrats were used to form a composite data matrix of 30 samples (Appendix C), as 10 quadrats had 50% or more rock. Multivariate analyses were applied to 47 species out of a t o t a l of 54, as 7 species occurred in less than 5 composite samples. The transect i s characterized by high cover values for Kobresia myosuroides in samples 1-11 (range 13-58%; mean 40%), with t h i s species v i r t u a l l y absent from the remaining samples. Carex scirpoidea occurs in a l l samples with cover values ranging from 6-48% (mean 28%). Cetraria n i v a l i s (6-30% cover), Cetraria cucullata (5-20%), Cornicularia aculeata (5-20%), and Arenaria obtusiloba (5-20%) are s i m i l a r l y ubiquitous. Multivariate analyses: 55 A centered PCA was applied to the data set, and the resulting f i r s t two component axes accounted for 77% of sample v a r i a t i o n . The f i r s t two axes of a centered and standardized PCA, and a RA accounted for 32% and 52% of sample v a r i a t i o n , respectively (Fig. 8). Each of these analyses (including plots of axes 1 and 3) indicated two large, d i s t i n c t groups of samples 1-11 (dominated by Kobresia myosuroides) and samples 12-30 (dominated by Carex scirpoidea [mean 36% cover]). These groups were not clear with axes 2 and 3. Low values for Carex scirpoidea (mean 16%) occur in the 1-11 group, as well as consistently high values for Cetraria cucullata (mean 14%), compared to the remaining samples (mean 5%). Samples 19 and 26 are outlying in the centered PCA and RA scatter plots (30% and 22% cover of Silene acaulis, respectively), as i s sample 1 (12% Carex capitata, a species otherwise absent or present only in trace amounts). Cluster analysis resulted in two groups of samples 1-11 and samples 12-30, both a r e l a t i v e l y large distance from the f i n a l fusion of a l l samples. Within the 12-30 sample c l u s t e r , a subset of samples 13, 16, 19, 21, 23, and 26 appears, possibly due to their r e l a t i v e l y high Silene acaulis component. The cophenetic correlation for t h i s dendrogram i s .7646, implying a f a i r l y good i l l u s t r a t i o n of sample a f f i n i t i e s . Vegetation Groups: Sample groups for Transect E are as follows: 1) Samples 1-11, characterized by high cover of Kobresia myosuroides and correspondingly low cover of Carex scirpoidea. 56 Figure 8 - Transect E Multivariate Analyses CENTERED PRINCIPAL COMPONENTS ANALYSIS CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS . 2 3 *3 1 8 . 2 5 . 27 . 15 30 , 29 . 2 2 * 9 2* ' 3 2 3 . . 1 8 *27 ' 12 \u00E2\u0080\u00A2 1 6 2f to RECIPROCAL AVERAGING MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE . 16 24 . 1 8 27 14 15 . 22 2 8 * 10 2 9 . ' 17 . 8 . 9 -47 57 2) Samples 12-30, characterized by high cover of Carex scirpoidea, with l i t t l e or no Kobresia myosuroides. Corresponding po i n t - l i n e data w i l l be sub-divided into these two groups before association analysis. 6. Transect F; Thirty composite samples were formed from the complete o r i g i n a l data matrix of 90 quadrats (Appendix C). Forty-three species were used for multivariate analyses after the 3 species with less than 5 occurrences in the composite samples were deleted. The data set i s characterized by high cover values for Kobresia myosuroides (mean 49%) in samples 1-4, and 6-7, with lower amounts in samples 5, 8, and 9 (mean 18%). The remaining samples average 32% Carex capitata, with no Kobresia myosuroides. Carex scirpoidea i s a variable dominant throughout the data set, ranging from 5-43% cover and averaging 24%. Multivariate Analyses: Analysis by centered PCA, centered and standardized PCA, and RA (Fig. 9) resulted in the f i r s t two axes accounting for 68%, 31%, and 47% of sample v a r i a t i o n , respectively. The v a r i a b l i l i t y of samples i s indicated, p a r t i c u l a r l y in the standardized PCA scatter diagram. Samples 1-4, 6, and 7 show a f f i n i t y in a l l three analyses. Samples 5, 8, and 9 (averaging 20% Carex capitata, 24% Carex scirpoidea, and 18% Kobresia myosuroides) occur in a somewhat intermediate position between t h i s group and the remaining sample points in the centered PCA and RA scatter plots, with samples 25 and 26 included with these intermediates 5 8 Figure 9 - Transect F Multivariate Analyses CENTERED PRINCIPAL COMPONENTS ANALYSIS CENTERED AND STANDARDIZED PRINCIPAL COMPONENTS ANALYSIS 2 9 . , , 22 \u00E2\u0080\u00A2 . * 2 ' . 8 \u00E2\u0080\u00A2 9 * 3 0 \u00E2\u0080\u00A224 \u00E2\u0080\u00A2 2 6 . 2 5 . 30 \"28 2 3 * \u00C2\u00BB 9 . 18 * 1 5 , 16 *5 ' 7 . 6 . 26 RECIPROCAL AVERAGING MINIMUM VARIANCE CLUSTER ANALYSIS USING EUCLIDEAN DISTANCE * 3 0 28* 27 \ 'A \u00E2\u0080\u00A2 III . '5 59 in the centered PCA scatter plot of axes 1 and 3. Samples 25 and 26 are outlying in most ordinations, and have an average 42% cover of Carex scirpoidea with no Carex capitata or Kobresia myosuroides present. Sample 15 has high Carex capitata (57%) and low Carex scirpoidea (6%). The above a f f i n i t i e s were not i l l u s t r a t e d with axes 2 and 3 in any of the analyses. Cluster analysis produced a d i s t i n c t group of samples 1-4, and 6-7, a large distance from the f i n a l fusion of a l l samples. Samples 5, 8, and 9 group with the remaining sample points, which also fuse a large distance from the f i n a l linkage. The cophenetic c o r r e l a t i o n i s .8163, indicating that the dendrogram is a good i l l u s t r a t i o n of sample s i m i l a r i t i e s and differences. Vegetation Groups: Sample groups within Transect F: 1) Samples 1-4, 6, and 7, dominated by Kobresia myosuroides, and averaging 16% Carex scirpoidea, with l i t t l e or no Carex capitata. 2) Samples 5, and 8-30, with an average of 30% Carex capitata and 27% Carex scirpoidea. Kobresia myosuroides i s absent in a l l samples except 5, 8, and 9. Point-line data for these two vegetation groups w i l l therefore be analyzed for associations separately. 60 7. A l l Transects: Composite samples from a l l six transects were compiled into one data set of 180 cases for additional multivariate analyses, to compare d i f f e r e n t stands of each community and to determine ov e r a l l relationships between sampled areas. Sixty-three species were used after deletion of 5 species which occurred in less than 5 of the 180 composite samples. Correspondence of sample points to o r i g i n a l data sets in Figures 10-13 i s indicated by symbols. Multivariate Analyses: Analysis with centered PCA resulted in 56% of sample va r i a t i o n accounted for by the f i r s t two axes (Fig. 10), while centered and standardized PCA and RA accounted for only 22% and 30%, respectively (Figs. 11, 12). The a f f i n i t y of samples dominated by Carex capitata and Carex scirpoidea (data sets A, B, C2, and F2) i s apparent with the f i r s t three axes of a l l three ordinations, with no samples grouped according to their o r i g i n a l data matrix. Group C1, with the additional dominant, Salix n i v a l i s , has the majority of i t s samples clustered together in the two PCA scatter plots, but a d i s t i n c t group of a l l these points occurs only with RA. Samples with high values for Kobresia myosuroides (data sets D1, E1, and F1) appear together in a l l ordinations. Samples co-dominated by Carex scirpoidea and Kobresia myosuroides (data set D2) occurred in an intermediate position between th i s group and samples dominated sol e l y by Carex scirpoidea (data sets D3 and E2) in the centered PCA and RA scatter pl o t s . Separation of Carex scirpoidea 61 Figures 10-13 - Ordination and Cluster Analysis of 11 Data Sets. Data sets are indicated by the following symbols in these figures: Data set A: \u00E2\u0080\u00A2 ; B: o ; C1: 0 ; C2: \u00E2\u0080\u00A2 ; D1: v ; D2: 4 \u00E2\u0080\u00A2 D3: \u00E2\u0080\u00A2 ; E l : + ; E2: t ; F1: * ; and F2: \u00E2\u0080\u00A2 . 62 Figure 10 - Centered PCA - A l l Data Sets AXIS 1 63 Figure 11 - Centered and Standardized PCA - A l l Data Sets \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 * + , 4 ! ' \u00E2\u0080\u00A2 v V o\u00C2\u00B0 \u00E2\u0080\u00A2 R?l \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 V V o *o * o \u00C2\u00B0 + + \u00C2\u00B0 o \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 o \u00E2\u0080\u00A2\u00E2\u0080\u00A2 mmom 0 v T \u00E2\u0080\u00A2 *\u00C2\u00BB\u00E2\u0080\u00A2 \u00E2\u0080\u00A2 o \u00E2\u0080\u00A2 00 AXIS 1 64 Figure 1 2 - RA - A l l Data Sets A X I S 1 65 dominated sample points from data sets D3 and E2 i s apparent with a l l analyses ( p a r t i c u l a r l y RA), possibly because of the appreciable Cornicularia aculeata and Silene acaulis components and higher t o t a l cover found in E2 (Appendices 1D and 1E). Cluster analysis (Fig. 13), corroborates sample a f f i n i t i e s i l l u s t r a t e d by ordination, with four major groups apparent. The two groups to the l e f t comprise Carex capitata/Carex scirpoidea dominated samples with the majority of samples containing Salix n i v a l i s forming a sub-cluster. Samples with high values for Kobresia myosuroides cluster to the right, a very large distance from the f i n a l fusion of a l l samples, with sub-groups cor r e l a t i n g to the o r i g i n a l data sets. The remaining samples are contained within a cluster a large distance from the cluster of samples high in Kobresia myosuroides, with further d i v i s i o n separating d i f f e r e n t Carex scirpoidea dominated data sets (D3 and E2). Intermediate Kobresia myosuroides/Carex scirpoidea dominated samples (with 1 \"high Kobresia myosuroides\" sample) form a small cluster within the larger grouping containing data set D3. The cophenetic c o r r e l a t i o n i s r e l a t i v e l y low at .5736, implying that some d i s t o r t i o n of sample a f f i n i t e s has l i k e l y occurred during dendrogram construction. Vegetation Groups: Analysis of compiled transect data sets supports the v a l i d i t y of vegetation groups determined by individual transect analysis. S i m i l a r i t y between Carex capitata/Carex scirpoidea dominated data sets i s i l l u s t r a t e d , as well as between s i t e differences in Carex scirpoidea dominated and Kobresia FIGURE 13 - CLUSTER A N A L Y S I S - A L L DATA SETS H39 67 myosuroides dominated vegetation. Phenology Phenological stages for a t o t a l of 45 vascular plant species were recorded during the summer of 1980, within permanent 2 m square plots in each sampled transect. Data corresponding to the 11 vegetation groups previously outlined are presented in Figs. 14-19. As phenology was, on average, recorded weekly, differences of less than 10 days in these figures w i l l not be discussed. The timing of phenological phases was quite d i f f e r e n t between species within each vegetation group. Although i n t r a s p e c i f i c differences were observed in vegetation sampled at d i f f e r e n t aspects, the duration of each phenological phase was comparatively consistent within a species. Snow release for a l l transects took place between June 16 and 18 in 1980. Most species flowered 15-40 days after snow release - a l l except Carex capitata had assumed at least vegetative growth at t h i s time. In general, flowering occurred for 18-40 days and f r u i t i n g for 10-30 days before seed d i s p e r s a l . Consistent exceptions to t h i s general trend include the late development of Sedum lanceolatum, P o t e n t i l l a f r u t i c o s a , and Solidago multiradiata (mid to late J u l y ) , and the early f l o r a l maturation of Draba incerta, Draba paysoni i , and Draba lonchocarpa, which flowered immediately after snow release. In addition, Taraxacum ceratophorum has a r e l a t i v e l y short flowering period ranging from 8-14 days and Dryas octopetala and Agoseris glauca flower for 10 days only. The f r u i t i n g period 68 Figures 14-19 - Phenology of vascular species within 11 vegetation groups from June 20 to Sept. 10, 1980. Soli d bars indicate the flowering period, and open bars containing D, V, F, and S indicate dormant, vegetative, f r u i t i n g , and seed dispersal stages, respectively. Vegetation was completely snowfree by JUne 20, 1980. 69 Figure 14 - Transect A Phenology ANDROSACE SEPTENTRI ONAI IS ANTENNARIA ALP INA ARENARIA OBTUSILOBA CAREX CAPITATA CAREX NARDINA CAREX SCIRPOIDEA CERASTIUM BEER INGIANUM DRABA INCERTA DRABA PAYSONII ERIGERON AUREUS FESTUCA OVINA HAPLOPAPPUS LYALLI I LUPINUS LYALLI I LUZULA CAMPESTRIS OXYTROPIS MONT I COLA PENSTEMON PROCERUS POA RUPESTRIS POLEMONIUM PULCHERRIMUM POLYGONUM VIVIPARUM POTENTILLA DIVERS IFOLIA POTENTILLA NIVEA SALIX NIVALIS SEDUM LANCEOLATUM SENECIO LUGENS SILENE ACAULIS SOL I DAGO MULT I RAD I ATA STELLARIA LONGIPES TRISETUM SPICATUM Figure 15 - Transect B Phenology 10/8 20/8 30/8 10/S 70 Figure 16 - Transect C Phenology GROUP C1 GROUP C2 20/6 30/6 i r 10/7 20/7 I F IS Ll_ s s F s \u00E2\u0080\u00A2 P i S 30/7 10/8 20/8 30/8 10/9 71 Figure 17 - Transect D Phenology GROUP D1 GROUP D2 ANTENNARIA ALP INA ARENARIA OBTUSILOBA CALAMAGROSTIS PURPURASCENS CAREX SCIRPOIPEA CERASTIUM BEER INGIANUM DRABA CANA DRABA INCERTA DRABA PAYSONI I ERIGERON COMPOSITUS FESTUCA OVINA HAPLOPAPPUS LYALLI I KOBRESIA MYOSUROIDES OXYTROPIS MONT I COLA POTENTILLA DI VERS IFOL tA POTENTILLA NIVEA SEDUM LANCEOLATUM SILENE ACAULIS SOL I DAGO MULT I RAD I ATA TARAXACUM CERATOPHORUM TRISETUM SPICATUM GROUP D3 20/6 30/6 10/7 20/7 30/7 30/8 10/9 72 Figure 18 - Transect E Phenology GROUP GROUP 20/6 3o\"/6 \U/7 20/7 30/7 10/8 20/8 30/8 10/9 73 Figure 19 - Transect F Phenology GROUP F1 GROUP F 2 CAREX NARDINA I CAREX PHAEOCEPHALA CAREX SCIRPOIDEA I CERASTIUM BEER INGIANUM I DRABA INCERTA J DRABA PAYSONII I ANDROSACE SEPTENTRIONALIS ANTENNARIA UMBRINELLA ARENARIA OBTUSILOBA CAREX CAPITATA ERIGERON AUREUS FESTUCA OVINA HAPLOPAPPUS LYALLI I LUPINUS LYALLI I LUZULA CAMPESTRIS OXYTROPIS MONT I COLA PENSTEMON PROCERUS POA SP. POTENTILLA DIVERSIFOLIA POTENTILLA NIVEA SEDUh LANCEOLATUM SENECIO LUGENS SILENE ACAULIS SOL I DAGO MULTIRAD I ATA STELLARIA LONGIPES TRISETUM SPICATUM 20/6 \u00E2\u0080\u0094 i ' r 30/6 10/7 20/7 30/7 10/8 20/8 30/8 10/9 74 for Taraxacum ceratophorum i s 6-10 days, and the complete f r u i t i n g period for Sedum lanceolatum lasted less than 6 days when observed. Major phenological differences between vegetation groups at a constant aspect and between the same community types at d i f f e r e n t aspects w i l l be outlined in the following sections. 1. Constant Aspect; Transect C (N29\u00C2\u00B0E): The phenology of vascular species in groups C1 and C2 i s es s e n t i a l l y the same, with only two species d i f f e r i n g by 10 days or more. Poa alpina flowers 16 days e a r l i e r , and Carex nardina 10 days l a t e r , in C1 than in C2. Flowering periods for these two species terminate at the same time in both groups. Transect D (S2\u00C2\u00B0E): Three species have major phenological differences within th i s transect. Arenaria obtusiloba and Oxytropis monticola flower an average of 15 days e a r l i e r in group D3. Kobresia myosuroides flowers 14 days longer in group D2 than in group D1, with f r u i t i n g beginning 10 days later as well. Transect E (N16\u00C2\u00B0W): The majority of species within t h i s transect have similar phenological timing. A few species, however, tend to flower e a r l i e r in group E2 than in group E1. Senecio lugens, Haplopappus l y a l l i i , \u00E2\u0080\u00A2 and Carex scirpoidea flower 10 days 75 e a r l i e r , although the duration of flowering i s the same in both groups. Trisetum spicatum flowers 16 days e a r l i e r and Cerastium beeringianum 20 days e a r l i e r in E2. Transect F (S56\u00C2\u00B0E): \u00E2\u0080\u00A2 ' Many species have similar phenological timing within this transect, although several species flower later in group F1 than in group F2. Carex nardina, Carex scirpoidea, Cerastium beeringianum, and P o t e n t i l l a d i v e r s i f o l i a flower 10-16 days later in F1 . 2. Constant Community Type: Carex capitata/Carex scirpoidea Community Type (Groups A, B, C2, F2): Species generally begin periods of flowering and f r u i t i n g sooner in group F2 (S56\u00C2\u00B0E) than in groups A (N58\u00C2\u00B0W), B (S80\u00C2\u00B0W), and C2 (N29\u00C2\u00B0E). For example, P o t e n t i l l a d i v e r s i f o l i a , P o t e n t i l l a nivea, Oxytropis monticola, Haplopappus l y a l l i i , Erigeron aureus, and Androsace septentrional i s flower and/or f r u i t 10-16 days e a r l i e r in F2 than in the other groups. A few species flower 12-18 days later in C2 than in the remaining groups (e.g., Cerastium beeringianum, Carex scirpoidea, and Carex nardina). The duration of flowering i s 16-20 days longer for S t e l l a r i a longipes in thi s group. Some exceptions to thi s general trend are evident. Flowering occurs l a t e s t in group B (14-20 days) for Solidago multiradiata, Polemonium pulcherrimum, and Trisetum spicatum, 76 and la t e s t in group A (10-12 days) for Penstemon procerus. Seed dispersal of Draba paysonii occurs 10 days e a r l i e r in north-facing groups (A and C2) than in south-facing groups (B and F2), while Silene acaulis begins seed dispersal 10 days e a r l i e r in F2 than in C2. Carex scirpoidea Community Type (Groups D3 and E2): In general, species begin phenological phases e a r l i e r in group D3 (S2\u00C2\u00B0E) than in group E2 (N16\u00C2\u00B0W), or at similar times in both groups. A number of species flower 10-20 days sooner in group D3: Festuca ovina, Draba paysoni i , Polemonium pulcherrimum, Oxytropis monticola, Silene acaulis, Taraxacum ceratophorum, P o t e n t i l l a d i v e r s i f o l i a , and P o t e n t i l l a nivea. In addition, Taraxacum ceratophorum and P o t e n t i l l a nivea f r u i t 10 days e a r l i e r and Silene acaulis and Erigeron compositus begin seed dispersal 10 days e a r l i e r in D3. Kobresia myosuroides Community Type (Groups D1, E1, and F1): Phenological stages tend to be i n i t i a t e d e a r l i e s t in group D1 (S2\u00C2\u00B0E) and la t e s t in group E1 (N16\u00C2\u00B0W). For example, Trisetum spicatum flowers 10 days sooner in D1 than in F1 (S56\u00C2\u00B0E), and 18 days e a r l i e r in D1 than in E1. Silene acaulis, P o t e n t i l l a d i v e r s i f o l i a , P o t e n t i l l a nivea, and Kobresia myosuroides a l l flower 10-16 days e a r l i e r in D1 than in the remaining groups and Sedum lanceolatum flowers 24 days l a t e r in E1 than in D1 and F1. Cerastium beeringianum flowers 12 days sooner in Fl than E1 ( i t does not occur in D1). Carex scirpoidea i s an exception to t h i s 77 trend, flowering 12-15 days later in F1 than in E1 and D1. I n t e r s p e c i f i c Associations Positive and negative associations for 11 vegetation groups are given in Figs. 20-31. Species are indicated by three-letter codes in these figures and are l i s t e d in Table IV. Table IV - Associated Species AGL - Agoseris glauca (Pursh) Raf. AAL - Antennaria alpina (L.) Gaertn. AOB - Arenaria obtusiloba (Rydb.) Fern. CPU - Calamagrostis purpurascens R. Br. *CAL - Caloplaca sp. Th. Fr. *CAN - Candelariella sp. Mull. Arg. CCA - Carex capitata L. CNA - Carex nardina Fries CPH - Carex phaeocephala Piper CSC - Carex scirpoidea Michx. CBE - Cerastium beeringianum Cham. & Schlecht *CCU - Cetraria cucullata (Bell.) Ach. *CIS - Cetraria islandica (L.) Ach. *CNI - Cetraria niva1is~T l.) Ach. *CMI - Cladina mitis (Sandst.) Hale & Culb. *CCH - Cladonia chlorophaea (Florke ex Somm.) Spreng. *CLA - Cladonia sp. Wigg. *CAC - Cornicularia aculeata (Schreb.) Ach. nDES - Desmatodon sp Br i d . DIN - Draba incerta Pays. DLO - Draba lonchocarpa Rydb. DPA - Draba paysoni i Macbr. DOC - Dryas octopetala L. EAU - Erigeron aureus Greene ECO - Erigeron compositus Pursh FOV - Festuca ovina L. HLY - Haplopappus l y a l l i i Gray KMY - Kobresia myosuroides ( V i l l . ) F i o r i *LVU - Letharia vulpina (L.) Hue LLY - Lupinus l y a l l i i A. Gray LCA - Luzula campestris (L.) DC. *OUP - Ochrolechia upsaliensis (L.) Mass. OMO - Oxytropis monticola Gray *PCA - Peltigera canina (L.) Willd. PPR - Penstemon procerus Dougl. PRU - Poa rupestris Vasey POA - Poa sp. L. 78 PPU - Polemonium pulcherrimum Hook. nPJU - Polytrichum juniperinum Hedw. nPPI - Polytrichum p i l i f e r u m Hedw. PDI - P o t e n t i l l a d i v e r s i f o l i a Lehm. PFR - P o t e n t i l l a f r u t i c o s a L. PNI - P o t e n t i l l a nivea L. SNI - Salix n i v a l i s Hook. SLA - Sedum lanceolatum Torr. SDE - Selaqinella densa Rydb. SLU - Senecio lugens Rich. SAC - Silene acaulis L. SMU - Solidaqo multiradiata A i t . SLO - S t e l l a r i a lonqipes Goldie TCE - Taraxacum ceratophorum (Ledeb.) DC. *TVE - Thamnolina vermicular i s (Sw.) Ach. ex TSP - Trisetum spicatum (L.) Richter BLA - Bare ground Schaer, Lichen species in thi s l i s t are i d e n t i f i a b l e by a *, and moss species by a n. Of the species sampled, 88% had at least one association in at least one vegetation group. 1 . Transect A: Point-line data from the entire transect were used in association analysis. This data set of 9285 points comprised 41 vascular, lichen, and moss species (species which had less than 5 occurrences were grouped into a miscellaneous category). A t o t a l of 38 s i g n i f i c a n t (p<0.05) posit i v e associations and 31 si g n i f i c a n t (p<0.05) negative associations (Fig. 20) were detected, out of a possible 861 d i f f e r e n t species-pair combinations. Carex capitata, one of two dominant vascular species, i s s i g n i f i c a n t l y p o s i t i v e l y associated with 3 lichens and 2 vascular species, while co-dominant, Carex scirpoidea, i s p o s i t i v e l y associated with 5 vascular plants. Carex capitata and Carex scirpoidea are negatively (p<0.05) associated with 7 and 3 species, respectively. The lichen, Cetraria i s l a n d i c a , i s 79 Figures 20-31 - Positive and negative associations between species pairs in 11 vegetation groups. Species are indicated by three-letter codes and are connected by , , or , indicating p<0.05, p<0.0l, and p<0.00l levels of significance, respectively. 80 F i g u r e 20 - G r o u p A P o s i t i v e a n d N e g a t i v e A s s o c i a t i o n s P O S I T I V E S D E CCH NEGATIVE L L Y P D T V E _ \" _ ' _ _ ecu P P C N I S L O S N I C C H O U P \u00E2\u0080\u00A2 A O B OMO 81 negatively associated with 7 species (including 2 lichens) as well as bare ground. 2. Transect B: The p o i n t - l i n e data set of 9298 points was not subdivided before analysis of the 40 plant species. Forty-four s i g n i f i c a n t positive and 27 s i g n i f i c a n t negative associations (Fig. 21) occurred out of the 820 d i f f e r e n t species-pair combinations possible. Carex scirpoidea was p o s i t i v e l y associated with 5 vascular species and negatively associated with 2 lichens. Co-dominant, Carex capitata, was involved in 4 p o s i t i v e associations (3 with lichen species) and 7 negative associations (6 vascular species and 1 moss). Other major species include Arenaria obtusiloba (6 p o s i t i v e associations), Cetraria cucullata (5 negative associations), and Selaginella densa (5 negative associations). 3. Transect C: Based on results of quadrat data analysis, p o i n t - l i n e data were sub-divided into two groups before analysis. Group C1 was dominated by Salix n i v a l i s , Carex scirpoidea, and Carex capitata. Group C2 was dominated by Carex scirpoidea and Carex capitata but had no Salix n i v a l i s . Group C1: Data involving 3897 points and 44 species were used in association analysis. A t o t a l of 40 s i g n i f i c a n t (p^0.05) positive and 18 s i g n i f i c a n t negative associations (Fig. 22) were 82 Figure 21 - Group B Positive and Negative Associations P O S I T I V E D E S T V E C I S C M I C N A \u00E2\u0080\u00A2\u00E2\u0080\u00A2\u00E2\u0080\u00A2 A O B . \u00E2\u0080\u00A2 \u00E2\u0080\u00A2' t '\u00E2\u0080\u00A2 / ' P P R C S C T S P / \ / _ _ S A C C B E S M U ecu / ^ P D I \ A . . E A U P P I C C H P C A S D E 0 U P C C A _ _ _ _ _ ' C A C . - C N I H LY NEGATIVE C N I 83 F i g u r e 22 - G r o u p C l P o s i t i v e a n d N e g a t i v e A s s o c i a t i o n s P O S I T I V E p D , D O C C N I P PR E A U C C A C I S C S C C A C C NA L C A A O B ecu- TVE B L A OMO X ^ S L U \" S L O O U P SOE P P I C L A L L Y P C A A A L . .': S N I F O V _ _ - - S A C D P A T S P P R U NEGATIVE D PA S O E \" C I S - - ' . P P I S L O T V E S A C C C A L L Y / C N I C L A C S C B L A ecu 84 detected out of 990 possible species-pair combinations. Salix n i v a l i s has the greatest number of s i g n i f i c a n t associations: 11 positive with vascular species and bare ground and 5 negative -4 with lichens and 1 with Carex capitata. Carex capitata i s p o s i t i v e l y associated with 4 lichens and 3 vascular species and negatively associated with 2 lichens and 3 vascular plants. Carex scirpoidea has 3 posit i v e associations with vascular species and 1 negative association with bare ground. Cetraria islandica has a t o t a l of 7 negative associations. Group C2: Point-line data comprising 5470 points and 43 species were analyzed. Thirty-four s i g n i f i c a n t p o s i t i v e associations and 17 s i g n i f i c a n t negative associations (Fig. 23) occurred out of 946 possible species pair combinations. The co-dominant vascular species, Carex capitata and Carex scirpoidea, were p o s i t i v e l y associated with vascular species only; 3 and 2, respectively. Carex capitata has 5 negative associations, including 1 lichen and Carex scirpoidea i s negatively associated with 2 vascular species. Other major species include Arenaria obtusiloba (4 positive associations), and Cetraria islandica (4 negative associations). 4. Transect D: Point-line data were sub-divided into three groups based on quadrat data analysis. Kobresia myosuroides i s the vascular dominant of group D1, and Carex scirpoidea of group D3. Group D2 is a t r a n s i t i o n zone with Kobresia myosuroides and Carex 85 Figure 23 - Group C2 Positive and Negative Associations P O S I T I V E NEGATIVE KMY C N I I I I I C A C C N A ecu C I S S L U O U P T V E / / / B L A L L Y S D E C L A S L O *~ P P I P PR I T S P A O B ' E A U C P H C C A I I I C S C / I I L C A P D I \" C B E O M O .. S A C \u00E2\u0080\u00A2 F O V S L O C L A C N I P D I O M O C S C C I S C P H C C U F O V T S P S D E C C A T V E S A C K MY C A C P P I A 0 B P P R 86 scirpoidea as co-dominants. Group D1: This data set comprises 25 species (2122 points) and has comparatively few s i g n i f i c a n t associations - 13 p o s i t i v e and 4 negative (Fig. 24), with 325 species-pair combinations possible. Kobresia myosuroides was p o s i t i v e l y associated with 2 lichens and 1 vascular species and negatively associated with only 1 lichen species. Group D2: The t r a n s i t i o n a l grouping of 1303 points includes data for 25 species. A t o t a l of 11 s i g n i f i c a n t positive and 3 s i g n i f i c a n t negative associations were detected (Fig. 25), with 325 species-pair combinations possible. Kobresia myosuroides has 3 p o s i t i v e associations (with 2 lichens and 1 vascular species) and 2 negative associations, with 1 lichen and with Carex scirpoidea. Carex scirpoidea i s p o s i t i v e l y associated with 2 vascular species. Group D3: This larger data set (4362 points) contains data for 38 species. Twenty-five s i g n i f i c a n t positive and 6 s i g n i f i c a n t negative associations (Fig. 26) occurred out of 741 possible species-pair combinations. The dominant vascular species, Carex scirpoidea, was p o s i t i v e l y associated with 2 vascular species and negatively associated with bare ground. Other major species include Arenaria obtusiloba (4 positive associations), Selaginella densa (5 p o s i t i v e , 3 negative), and Cetraria islandica (3 p o s i t i v e ) . 87 Figure 24 - Group D1 Positive and Negative Associations P O S I T I V E ecu C A C L V U C N I K M Y A A L P D I A O B C S C S M U / B L A P J U T C E O U P S D E C L A C A N NEGATIVE A \u00C2\u00B0 B C L A K M Y C N I S D E C S C B L A 88 Figure 25 - Group D2 Positive and Negative Associations P O S I T I V E A O B P N I C L A B L A S L A T C E C S C S M U C A N C A C H L Y P D I K M Y NEGATIVE C I S C N I e c u C L A K M Y C S C C A C P D I 89 Figure 26 - Group D3 Positive and Negative Associations P O S I T I V E C S C A G L O M O C L A C A N p p i B L A -S M U P N I A O B T C E A A L P C A S O E T S P P D I C C U C N A O U P P F R F O V S A C C A C C N I C I S C P U NEGATIVE C S C B L A S M U C C U C L A A O B S D E T C E 90 5. Transect E: Sub-division of poi n t - l i n e data into two groups occurred before association analysis. Group E1 was dominated by Kobresia myosuroides and group E2 by Carex scirpoidea, with Kobresia myosuroides v i r t u a l l y absent. No t r a n s i t i o n zone was i d e n t i f i e d . Group E1: Data comprising 3447 points and 35 species were analyzed. A t o t a l of 30 s i g n i f i c a n t positive and 14 s i g n i f i c a n t negative associations were detected (Fig. 27), with 630 di f f e r e n t species-pair combinations possible. Kobresia myosuroides was p o s i t i v e l y associated with 4 lichen species and negatively associated with 3 vascular species, 1 lichen, 1 moss, and bare ground. Nine species were p o s i t i v e l y associated and 2 species negatively associated with bare ground. Other major vascular species include Selaginella densa (4 positive associations, 1 negative), Arenaria obtusiloba (4 po s i t i v e , 2 negative), and Carex scirpoidea (4 pos i t i v e , 1 negative). Group E2: This data set contained 6117 points for 43 species. Thirty-eight s i g n i f i c a n t p o s i t i v e assocations and 17 s i g n i f i c a n t negative associations (Fig. 28) occurred out of 946 possible species-pair combinations. The dominant vascular species, Carex scirpoidea, has no s i g n i f i c a n t p o s i t i v e associations and only 1 s i g n i f i c a n t negative association with a moss (Polytrichum p i l i f e r u m ) . Several less abundant species had a r e l a t i v e l y large number of associations, for example, Silene acaulis (8 91 Figure 27 - Group E1 Positive and Negative Associations P O S I T I V E L V U O U P T S P P D 1 C M I NEGATIVE S D E C S C C C U C N I T V E \ \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \ .\u00E2\u0080\u00A2 \u00E2\u0080\u00A2 N s \ A O B ' / P I O U P / / / . . K M Y B L A C I S F O V \" / / C L A L C A 92 Figure 28 - Group E2 Positive and Negative Associations P O S I T I V E D L O E A U A O B \u00E2\u0080\u009E E C O D I N T C E L L Y C A C ... O U P \ \ \ C A L C N A C I S C N I i I S D E P P I C L A ' S L O B L A I i C C U ~ ~ - S A C .. F O V T V E S M U T S P \u00E2\u0080\u00A2 H L Y C B E P R U O M O L C A NEGATIVE P P I C S C B L A P D C L A P N I A O B C A C C N A S D E T V E S A C C N I / F O V C C U L L Y ^ O U P -93 positive associations, 4 negative), Selaginella densa (6 pos i t i v e , 5 negative), Arenaria obtusiloba (4 p o s i t i v e , 4 negative), and Ochrolechia upsaliensis (5 p o s i t i v e , 4 negative). 6. Transect F; Based on results of quadrat data analysis, p o i n t - l i n e data were sub-divided into two groups. Kobresia myosuroides i s the vascular dominant of group F1 and Carex scirpoidea and Carex capitata are vascular co-dominants of group F2. Group F1: Data involving 1822 points and 27 species were used in association analysis. Seventeen s i g n i f i c a n t p o s i t i v e and 8 s i g n i f i c a n t negative associations (Fig. 29) were detected from 378 possible species-pair combinations. Kobresia myosuroides was p o s i t i v e l y associated with 3 vascular species and bare ground and negatively associated with 2 vascular species and 1 lichen. Other major species include Selaginella densa (4 positi v e associations, 4 negative), and Cetraria is l a n d i c a (4 po s i t i v e , 2 negative). Group F2: The data set of 8178 points comprised 39 plant species. The largest number of s i g n i f i c a n t associations occurred in this data set - 54 posit i v e (Fig. 30) and 43 negative (Fig. 31), out of 780 possible species-pair combinations. Carex scirpoidea i s p o s i t i v e l y associated with 4 vascular species and 1 moss and negatively associated with 2 lichens and the vascular co-dominant, Carex capitata. Carex capitata i s p o s i t i v e l y 94 Figure 29 - Group F1 Positive and Negative Associations P O S I T I V E B L A P C A A O B K M Y L L Y S D E C L A P O A C A C O U P C S C C C A C I S C C U S L O P J U F O V C N I T V E NEGATIVE C A C C I S A O B I S D E K M Y C C A C C U C L A 95 Figure 30 - Group F2 Positive Associations L L Y 96 Figure 31 - Group F2 Negative Associations 97 associated with 2 vascular species and 5 lichens and negatively associated with 5 vascular species, one lichen, and bare ground. Other important species include Arenaria obtusiloba (6 positive associations, 6 negative associations), Polytrichum p i l i f e r u m (7 po s i t i v e , 5 negative), Cornicularia aculeata (6 pos i t i v e , 6 negative), Ochrolechia upsaliensis (7 pos i t i v e , 3 negative), Cladonia sp. (5 pos i t i v e , 7 negative), and Sel a g i n e l l a densa (5 pos i t i v e , 4 negative). 7. A l l Transects: Positive Associations: S i g n i f i c a n t positive associations for 11 data- sets consist of 182 d i f f e r e n t species pair combinations (including bare ground), and are presented alphabetically, by species, in Table V. These comprise 4.4% of the t o t a l number of possible species-pair combinations summed over a l l data sets. Abundant species, other than dominants, tend to have a greater number of di f f e r e n t associations than species with lower counts. The ubiquitous Arenaria obtusiloba had the largest number of d i f f e r e n t p o s i t i v e associations (22), while some rare species such as Calamagrostis purpurascens, Draba lonchocarpa, and P o t e n t i l l a fruticosa were p o s i t i v e l y associated only once. Carex scirpoidea has very few posit i v e associations where i t i s the vascular dominant - 2 in group D3 and zero in group E2. Many more associations occurred where thi s species was a co-dominant with Carex capitata. 98 Table V - Positive Associations for 11 Sample Groups. These are presented alphabetically with respect to species. Numerals refer to the number of times each species was contacted in each data set. Lichen species are indicated by a \u00E2\u0080\u00A2 and moss species by a n. Species codes are given under each species heading and are formed from the f i r s t l e t t e r of the generic epithet and the f i r s t two l e t t e r s of the s p e c i f i c . Associations for each species are indicated by codes, with *, **, and *** refering to p<0.05, p^O.01, and p^O.001 levels of significance, respectively. 99 POSITIVE INTERSPECIFIC ASSOCIATIONS TRANSECT A B Cl C2 01 D2 D3 El E2 Fl F2 DOMINANT CSC CSC SNI CSC KMY CSC CSC KMY CSC KMY CSC VASCULAR CCA CCA CSC CCA KMY CCA SPECIES CCA Agoser fs - - - - - - 31 gl auca CSC* (AGL) CLA* Antennar la 17 - 13 11 10 16 62 49 a l p l n a SNI* (AAJL) AOB*** PNI*** A rena r l a 402 410 208 299 244 128 460 192 390 105 501 o b t u s i l o b a FOV*** FOV* FOV*** (AOB) CSC** CSC* CSC** CSC** CSC*** PDI* LCA* LCA* LCA** CCU** CCU* CCU** TVE* CNA* CBE* TSP*** TSP* TSP* TSP*** TSP*** CAC* SNI*** SLO** E AU* EAU* SLU* TCE** TCE* TCE* AAL*** PNI* SMJ* SMJ* BLA* BLA*** BLA*** DLO** LLY*** KMY*** Cal an ag ros t i s - - - - 13 9 72 purpurascens CIS*** (CPU) 1 00 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT CI C2 DI D2 D3 El E2 Fl F2 Ca lop I aca sp . (CAL) 17 SAC*** 18 29 OUP*** CLA*** C a n d e l a r l e l l a sp . (CAN) 17 17 CLA*** KMY* 33 BLA* 1 7 Carex 1186 1709 310 784 - - 1 6 - 36 1312 c a p i t a t a ecu*** ecu*** ecu** ecu** (CCA) CNI*** CNI** CNI* CNI** CBE* CBE*** SL0**\u00C2\u00BB CIS* CIS*** CIS*** CIS* CIS*** HLY* PDI*** PDI** EAU* TVE** DOC* CPH** PPI CSC* PDI CMI * * LLY** CAC* Carex nardIna (CNA) 254 CAC*** OUP*** PPR** 46 AOS* 1 8 CAC*** 1 6 44 CNI 78 CAC** CNI SDE* 207 CAC*** OUP*** CN I * * * OMO*** PDI*** Carex phaeocephal a (CPH) 43 CCA** -j-yjr*** 1 5 101 TRANSECT Cerastium POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) B Cl C2 0! D2 D3 El E2 Fl F2 Carex 1088 962 230 677 120 s c i r p o i d e a 0M0*** OMO* (CSC) O O* PDI** poi* PDI\u00C2\u00BB* AOB** AOB* AOB** SAC*** SAC* PPR*** PPR*** PPR** 168 812 227 854 OMO*** PDI* AOB** SAC** PPU* SMJ* EAU\u00C2\u00AB SMU** SMU*** TCE** 42 beer i ng I an un CCA* (CBE) CNI* AOB* 1 7 CCA*** AGL* PNI* 106 780 CCA* 23 HLY*** AOB*** PPR*** DES*** HLY** TSP** 26 C e t r a r i a 620 768 176 349 54 26 52 261 195 100 589 cucul 1 ata CCA*** CCA*** CCA** CCA** (CCU) PDI * PDI** FOV** FOV* AOB** AOB* AOB** TVE** TVE*** SLU* SLU*** CIS** CIS* C l S * * * CIS*** CIS** CIS*** KMY*** KMY* KMY*** KMY*** CMI** SLO*** Cetrar1 a 1261 869 294 504 83 44 134 192 100 1 1 1 687 Is1 and ica CNI*** CN1*** CN1*** CNI** CN1** CNI** CNI*** (CIS) TVE*** j y \u00C2\u00A3 * * * TVE*** TVE*** CCA* CCA*** CCA*** CCA* CCA*** CMI*** CCU* CCU* ecu*** ecu*** ecu*** ecu*** PFR*** CPU*** LVU* 1 02 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 DI D2 D3 El E2 F2 (CNI ) Ce t r a r I a 479 536 189 401 114 50 138 391 541 96 431 niva l Is CCA*** CCA** CCA* CCA** CIS*** CIS*** CIS*** CIS** CIS** CIS*** CIS*** CAC*** CAC* CAC* CAC* CBE* FOV* CNA** CNA* CNA*** KMY*** KMY* KMY** LVU** LVU** PPI PPI 1 PDI 1 CI adIna m I t l s (CMI ) 39 71 CIS*** 1 5 ecu* 1 5 CCA** CAC*** C ladon ia 26 37 chiorophaea SDE** (CCH) CLA*** CLA*** CAC* PPI*** 28 CLA** PPI*** CIadon ia sp. (CLA) 1 1 5 147 89 54 78 43 138 67 1 1 1 60 208 SDE*** SDE*** SDE*** SDE* SDE** SDE*** SDE*** SDE*** SDE*** SDE*** CCH*** CCH*** CCH** EAU*** CAC* PPI*** p p | * * * DPA** PPI*** BLA* BLA* PCA*** PPI** BLA** PPI*** BLA** PCA*** PPI*** PCA*** CAN*** PNI* AGL* CAL*** OUP** OUP** 103 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 01 D2 03 El E2 Fl F2 C o r n t c u l a r l a 322 232 54 93 114 82 449 327 682 97 470 acu lea ta PPI*** (CAC) CNA*** CNA*** CNA*** CNA*** SDE*** SDE*** SDE*** SDE* SDE*** SDE* OUP*** OUP** OUP* OUP** TVE** CNI*** CNI* CNI* CNI* CCH* CLA* AOS1 LLY*** LLY* KMY*** KMY* LVU** HLY**\u00C2\u00BB PNI CMI * * * CCA*** Degnatodon 11 13 1 5 30 9 7 6 sp . TVE* (DES) f SC* * * Draba 12 - 7 - - - 1 6 1 5 20 1 ncer ta BLA*** (DIN) OUP** Draba - 6 - - - - 6 - 20 I one hocarpa AOB** (DLO) Draba payson 11 (DPA) 40 1 8 33 SNI*** CLA** 1 1 24 3LA* 39 Dryas octopeta l a (DOC) 47 PDI*** CCA* E r lge ron aureus (EAU) 80 123 CLA*** FOV* FOV** PPI* 85 CCA* CSC* 71 11 25 6 73 PPI AOB* AOB* LLY* 1 04 TRANSECT POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) B Cl C2 01 02 D3 El E2 Fl F2 Er Igeron con pos l tus (ECO) 75 68 LLY** SDE*** OUP*** Festuca ov ina (FOV) 427 344 88 191 41 SAC*** SAC*** SAC** SAC*** AOB*** PPR*** OMO** OMO* EAU* EAU** SNI*** CNI* CCU** 39 1 12 73 201 57 SAC*** SAC*** SAC*** OMO* 255 SAC*** AOB*** CCU* SMU** SLU* PJU* Haplopappus lyal I i i (HLY) 16 11 14 CCA* 20 33 29 152 CAC* CBE*** LCA* SAC* Kobres ia myosuroides (KMY) 1 70 CCU*** 28 497 CCU*** CCU' CAC*** CNI*** CNI* PDI*** PDI** CAN* 558 ecu*** CAC* CNI** TVE* 476 CSC* 83 LLY* AOB*** BLA* POA* OUP** Le the r t a vul p ina (LVU) 14 27 CAC** CNI** 13 52 34 CIS* 55 28 CNI** 1 05 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 DI D2 03 El E2 LupInus lyal I I I (LLY) 58 SNI* 139 SNI*** p p , \u00C2\u00BB * \u00C2\u00BB 42 31 113 45 CAC*** SLO*** SDE*** 54 CAC* SDE*** SDE* SDE* BLA*** AOB*** ECO** KMY* CCA** EAU** Luzu la can pestr 1 s (LCA) 253 SAC** AOB* 179 19 65 12 30 AOB* AOB** 156 HLY* 20 112 OUP* Ochro lech la 42 45 13 20 69 31 99 76 238 40 127 u p s a l l e n s l s CAC*** CAC** CAC* CAC** (OUP) CNA*** CNA*** PPI*** PPI** SDE*** SDE** SDE*** SDE** SDE*** SDE*** SDE*** CLA** CLA** CAL*** DIN*** ECO*** LCA* KMY*** OxytropIs mont i co l a (OMO) 65 105 48 CSC*** CSC* FOV** SMJ*** SAC** SNI* 74 FOV* SAC* SLO* 74 CSC*** 34 12 FOV*** SAC*** 76 SMJ\u00C2\u00AB TSP* BLA*** CNA*** Pel t i g e r a - 13 16 12 8 9 30 14 8 11 28 canIna SDE*** SDE*** (PCA) SNI*** CLA*** CLA*** CLA*** PPI*** 106 POSITIVE INTERSPECIFIC ASSXIATIONS (continued) TRANSECT A B Cl C2 Dl D2 D3 E1 E2 Fl . F2 Penstemon 44 31 17 91 - - - - 40 163 procerus FOV*** (PPR) CSC*** CSC*** CSC** CSC*** CNA** SLO* PJU** SDE** Poa - 9 22 18 - - - - 50 rupes t r I s SNI* (PRU) SAC*** Poa 6 - - - - - - - - 1 0 1 4 sp . KMY* (POA) Polemon inn 21 23 pu lcher r in un CSC* (PPU) P o l y t r Ichum j un I per i nun (PJU) 13 22 BLA*** 34 46 54 FOV* PFR* Po ly t r i chun p i I i ferun (PPI ) 149 257 172 181 SNI*** CAC*** SDE* SDE*** SDE** SDE*** CLA*** CLA*** CLA*** CCH*** EAU* OUP*** LLY*** TVE** CNI*** 24 73 268 SDE* CLA** CLA*** 1 1 BLA*** BLA*** CCA*** CNI* 192 SDE*** CCH*** EAU** OUP** TVE** PCA* 1 07 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B Cl C2 Dl D2 D3 El E2 Potent 1 I la 551 641 128 341 137 65 207 37 144 d i v e r s l f o l la CSC** CSC* CSC** CSC* (PDI) AOB* CCU* CCU** CCA*** CCA** DOC*** SAC* SAC** KMY*** KMY** CNI** Potent I I la - - - - 17 - 22 f r u t i c o s a CIS*** (PFR) Potent I I la - - - - 25 40 165 25 96 n ivea AOB* (PNI) CLA* AAL*** TCE** SMJ* BLA*** CAC* CSC* Sa l Ix 73 - 607 niva l Is LLY*** LLY*** (SNI) PPI*** FOV*** BLA** AAL* SLO** AOB*** PRU* SAC*** OMO* TSP* PCA*** DPA*** Seduii 1 6 - 7 - - 9 - - 6 I anceol atun BLA*** (SLA) 1 0 8 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 01 D2 03 El E2 Fl F2 Se lag lne l la 299 205 62 104 148 49 268 98 296 101 269 densa CLA*** CLA*** CLA*** CLA* CLA** CLA*** CLA*** CLA*** CLA*** CLA*** (SDE) CCH** CAC*** CAC*** CAC*** CAC* CAC*** CAC* TVE* TVE* PPI* PPI*** PPI** p p | * * * PPI * p p , * * * PCA*** PCA*** OUP*** OUP** OUP*** OUP** OUP*** OUP*** OUP*** LLY*** LLY*** LLY* LLY* CNA* BLA* BLA** ECO*** PPR** Seneclo 27 39 38 33 - - 8 43 - 42 lugens CCU* CCU*** (SLU) AOB* FOV* S i I ene 117 96 113 131 - 12 27 68 205 10 86 acaul Is LCA** LCA* (SAC) FOV*** FOV*** FOV** FOV*** FOV*** FOV*** FOV*** FOV*** CSC*** CSC* CSC** CAL*** \u00E2\u0080\u00A2J-3P*** ygp*** TSP** OMO** OMO* OMO*** SMJ** SNI*** PDI* PDI** PDI * BLA** BLA** PRU*** SLO*** HLY* Sol tdago 69 192 - 18 13 26 146 - 24 17 125 m u l t i r a d l a t a OMO*** OMO** (SMU) SAC** CSC** CSC** CSC*** PNI* AOB* AOB* FOV** 1 09 TRANSECT POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) B Cl C2 Dl D2 03 El E2 Fl F2 S te l I a r i a long I pes (SLO) 99 106 CCA*** 38 AOB** SNI** 85 LLY*** OMO*** PPR* 33 198 SAC*\" CCU* Taraxacum - 19 26 77 23 ceratophorun AOB** AOB* AOB* (TCE) CSC** PNI** Thannol ina 777 796 259 451 verm i c u l a r i s Cl S*** Cl S*** Cl S*** CIS*** (TVE) CAC** SOE* AOB* DES* SDE* CCU** CCA** BLA CPH PPI** ** 1 5 I 46 90 38 212 CIS*** CIS*** ecu* CCU* KMY* Tr isetun 49 66 51 96 11 10 20 17 51 14 117 spicatuti SAC*** SAC*** SAC** (TSP) AOB*** AOB* AOB* AOB*** AOB*** SNM CSC** OMO* 1 10 POSITIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 DI D2 D3 El E2 Fl F2 Blank 49 20 138 29 178 133 333 265 477 16 219 (BLA) SNI** TVE** PJU*** CLA* CLA* CLA** CLA** SLA*** CAN* PPI*** p p | * * * SDE* SDE** AOB* AOB*** SAC** OMO*** KMY* DIN*** LLY*** DPA** 111 The positive associations detected by association analysis are too numerous to discuss i n d i v i d u a l l y . The following categories consider possible trends within these associations, based on their locations in the study area and gross species morphology. 1) Community and Aspect Relationships: Positive associations varied considerably between sampled s i t e s , with the majority showing no relationship to s p e c i f i c community types or aspects, or even the r e l a t i v e abundances of the species involved. Examples include the p o s i t i v e association of Arenaria obtusiloba with Trisetum spicatum (groups B, C2, D3, E1, and E2), and Lupinus l y a l l i i with Selaginella densa (groups C2, E1, E2, and F1). As well, associations e x i s t i n g each time a species pair occurs together are limited to very rare species (present in one or two data sets). Examples include the p o s i t i v e associations of Agoseris glauca with Carex scirpoidea and Cladonia sp. in group D3, Dryas octopetala with Arenaria obtusiloba in group C1, and Salix n i v a l i s with Lupinus l y a l l i i in groups A and C1. Only two associations between common species occurred everywhere counts greater than 25 were attained for both - Silene acaulis with Festuca ovina and Cladonia chorophaea with Cladonia sp. A small number of associations, however, do indicate trends based on certain communities and/or aspects. Nine positive associations are e s s e n t i a l l y r e s t r i c t e d to vegetation dominated by Carex capitata and Carex scirpoidea, although a few also 1 1 2 occur in group Fl , where these species are present, but not dominant. Several of these nine associations are r e s t r i c t e d to north aspects (e.g., Carex capitata with Cerastium beeringianum) or to south aspects (e.g., Erigeron aureus with Polytrichum p i l i f e r u m ) . No positive associations appear r e s t r i c t e d to the remaining vegetation types, although a small number appear excluded from them. For example, the association between Arenaria obtusiloba and Carex scirpoidea does not occur in Carex scirpoidea dominated vegetation, and Selaginella densa and Polytrichum piliferum are not associated in Kobresia myosuroides dominated areas where both are present. The occurrence of 7 p o s i t i v e associations appears related to aspect. For example, Kobresia myosuroides i s associated with Cetraria cucullata when they occur together, with the exception of two vegetation groups at S56\u00C2\u00B0E (transect F), and is also associated with Cornicularia aculeata at north aspects only (groups C2 and E1). Silene acaulis i s p o s i t i v e l y associated with bare ground in two vegetation groups at N16\u00C2\u00B0W (transect E) only. A large number of positive associations occur only once and may be either fortuitous or s p e c i f i c a l l y related to vegetation type or aspect. These include the association of P o t e n t i l l a nivea with Cornicularia aculeata and with Carex scirpoidea in group E1 (Kobresia myosuroides community type), and the association of Carex scirpoidea with Taraxacum ceratophorum in group D2 (Carex scirpoidea/Kobresia myosuroides dominated). 113 2) Associations Between Vascular Species: i) Monocot/Monocot Two percent (4) of the 168 d i f f e r e n t positive plant/plant associations are between two monocot species, and each of these occurs only once. Carex capitata i s p o s i t i v e l y associated with Carex phaeocephala and with Carex scirpoidea where they do not co-dominate. As well, Carex sc irpoidea i s associated with Trisetum spicatum, and Kobresia myosuroides i s associated with Poa sp. Only one monocot species (Kobresia myosuroides) was p o s i t i v e l y associated with bare ground. i i ) Dicot/Dicot Positive associations between dicot species are much more prevalent than those between monocots, and comprise 20% of the t o t a l number. Seventy-nine percent of these, however, occur only once. The most common positive dicot/dicot associations were detected a maximum of three times, e.g., Arenaria obtusiloba with Taraxacum ceratophorum, and Silene acaulis with Oxytropis monticola and with P o t e n t i l l a d i v e r s i f o l i a . Salix n i v a l i s has the largest number of d i f f e r e n t dicot associations -a l l occurring in group C1. In addition, the largest number of plant associations with bare ground (8) involved dicot species. i i i ) Monocot/Dicot Twenty-six percent of the p o s i t i v e plant/plant associations occur between monocot/dicot species pairs, with 63% of these 1 1 4 occurring only once. The most common monocot/dicot association is between Festuca ovina and Silene acaulis, and was detected 8 times (Silene acaulis was rare elsewhere). Other frequent associations include Carex scirpoidea with Arenaria obtusiloba (5 times), Solidaqo multiradiata (3), P o t e n t i l l a d i v e r s i f o l i a (4), and Penstemon procerus (4); Arenaria obtusiloba with Trisetum spicatum (5), and Festuca ovina (3); Carex capitata with P o t e n t i l l a d i v e r s i f o l i a (3); and Oxytropis monticola with Festuca ovina (3). 3) Associations Between Vascular Species and Lichens, Mosses, or Clubmoss: The largest number (30%) of positive species associations f a l l into t h i s category, with the involved vascular species divided almost evenly between monocots and dicots. Seventy-one percent of these associations occur only once, with the most frequently detected association occurring 5 times (Carex capitata with Cetraria i s l a n d i c a ) . Other frequent associations include Carex capitata with Cetraria n i v a l i s (4 times) and with Cetraria cucullata (4); Kobresia myosuroides with Cetraria cucullata (4) and with Cetraria n i v a l i s (3); and Lupinus l y a l l i i with the clubmoss, Selaginella densa (4). Twenty-five percent of the associations in t h i s category involve the two dominant species, Carex capitata and Kobresia myosuroides, while the t h i r d major dominant, Carex scirpoidea, has only one. 4) Associations Between Lichens, Mosses, and Clubmoss: 1 15 Associations in th i s category comprise 21% of the t o t a l number of positive species associations, with a r e l a t i v e l y small percentage (42) occurring only once. Some of the most frequently occurring positive associations f a l l into t h i s category - e.g., Selaginella densa and Cladonia sp. are associated in a l l groups except D2 (although counts over 40 occur for both here). Other frequent associations include Selaginella densa with Ochrolechia upsaliensis (7 times), Polytr ichum piliferum (6), and Cornicularia aculeata (5); Cetraria islandica with Cetraria n i v a l i s (7), Thamholina vermicularis (6), and Cetraria cucullata (6); and Cetraria n i v a l i s with Cornicularia aculeata (4). Six di f f e r e n t associations occur between bare ground and lichens, mosses, or clubmoss. Negative Associations: S i g n i f i c a n t negative associations for 11 data sets t o t a l 103 d i f f e r e n t species pair combinations (including bare ground) - 79 fewer than the s i g n i f i c a n t p o s i t i v e associations detected. S i g n i f i c a n t negative associations comprise 2.4% of the t o t a l number of possible species-pair combinations summed over a l l data sets, and are presented in Table VI. Abundant species tend to have the greatest number of d i f f e r e n t negative associations, as was apparent with pos i t i v e associations. Cetraria i s l a n d i c a and Carex capitata had 18 and 16 di f f e r e n t negative associations, respectively, while many less frequent species were involved in only one each (eg., Draba paysonii, Cladonia 1 16 Table VI - Negative Associations for 11 Sample Groups. The format is i d e n t i c a l to that for Table V. 1 1 7 NEGATIVE INTERSPECIFIC ASSXIATIONS TRANSECT A B CI C2 DI D2 D3 El E2 Fl F2 DOMINANT CSC CSC SNI CSC KMY CSC CSC KMY CSC KMY CSC VASCULAR CCA CCA CSC CCA KMY CCA SPECIES CCA ArenarI a 402 410 208 299 244 128 460 192 390 105 501 obtus i loba CAC** CAC* CAC* (AOB) CIS* CIS* SAC* PPI* PPI** PPI* SDE* SDE*** SDE* SDE* SDE** PPR* CLA* CLA* CLA* CLA* TVE** KMY*** PNI* CNA* CCA*** OUP* 1 709 CSC* PPI** SNI Carex 1186 709 310 c a p i t a t a CSC** (CCA) PPI* CCH* SNI* SDE** SDE** CLA*** CLA* FOV** FOV*** SAC* SAC* CNA* TSP* LLY* CAC* 784 1 6 36 SDE* FOV* SAC* 1312 CSC*** PPI*** CLA** FOV*** CNA* KMY* TVE* KMY*** KMY*** AOB*** BLA** 1 18 TRANSECT NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) B Cl C2 Dl D2 03 El E2 Fl F2 Carex nard ina (CNA) 254 CCA* 46 44 78 AOB* 207 CCA*** FOV* PPI * * CCU* CIS*** TVE* Carex phaeocephal a (CPH) 43 CSC* CIS* 1 5 Carex 1088 962 230 677 120 168 812 227 854 106 780 s c i r p o i d e a CCA** CCA* CCA*** (CSC) PPI** PPI* TVE** TVE* TVE* CCU** BLA* BLA* BLA*** SLO* CPH* KMY* CIS** C e t r a r i a 620 768 1 76 349 54 26 52 261 195 100 589 cucul 1 ata CNI*** CN1*** CN1*** CNI*** CNI*** (CCU) CLA* CLA** SDE** OUP* CSC** CLA** LLY** CLA* SDE** SDE* OUP** SDE*** SDE* OUP** LLY* CLA* SDE* OUP* SNI** CNA* OMO* 1 19 NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT Cl C2 Dl D2 03 El E2 Fl F2 Ce t r a r i a i si and lea (Cl S) 1261 869 SNI* OUP* OMO* BLA** AOB* AOB* CAC*** CAC*** CAC* SLO** SLO** SAC** SAC* FOV** PDI* PPI** SDE* DPA* LLY* 294 504 SNI*** OMO* CAC* 83 44 134 192 100 111 OUP* BLA** PDI CPH* 687 OUP*** #* run*** CAC** CAC SDE** SDE* CLA*** CNA*** CSC** TSP* C e t r a r i a n iv al is (CNI) 479 536 CCU*** CCU*** CLA* PDI** PDI* SDE* SDE* SLO* 89 401 114 CCU*** SDE* 50 138 SNI 391 541 CCU*** SDE* OUP* OUP** SAC*** 96 431 ecu*** CLA** SDE** SAC** PPI* C ladon ia chlorophaea (CCH) 26 CCA* 37 1 0 1 5 28 1 2 0 NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 DI D2 03 El E2 Fl F2 C ladon ia 115 147 89 54 73 43 138 67 111 60 208 sp . FOV* FOV* FOV* (CLA) CCA*** CCA* CCA** CNI * CNI** ccu* ecu** ecu** ccu* ecu* KMY* KMY** KMY* KMY* AOB* AOB* AOB* AOB* CIS*** PDI* CornicuI a r i a 322 232 54 93 114 82 449 327 682 97 470 acu lea ta CIS*** CIS*** CIS* CIS* CIS** CIS*** (CAC) AOB** AOB* AOB* CCA* PDI* SAC*** SAC** SLO* PPR* FOV* Draba 40 18 33 1 1 - 7 24 39 payson i I CIS* (DPA) Festuca 427 344 88 191 41 39 112 73 201 57 255 ov Ina CCA** CCA*** CCA* CCA*** (FOV) CLA* CLA* CLA* TVE** SDE* SDE** CIS** KMY* OUP* CNA* CAC* 1 2 1 NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT A B CI C2 DI 02 D3 El E2 Fl F2 Kobres ia - - - 28 497 170 - 558 - 476 83 myosuroides CCA* CCA*** CCA*** (KMY) CLA* CLA** CLA* CLA* CSC* PPI** BLA*** LCA** FOV* AOB*** SDE* LupInus lyal I I i (LLY) 58 TVE* 139 CIS* CCA* CCU** 42 31 113 CCU\" 45 54 Luzu la 253 179 19 65 - 12 30 156 20 112 canpes t r l s KMY** (LCA) Ochro lech ia 42 45 13 20 69 31 99 76 238 40 127 upsa l l ens t s CIS* CIS* CIS*** (OUP) ccu* ecu** ecu** ccu* CNI * CNI** SAC* FOV* AOB* Oxy t rop i s 65 105 48 74 - 74 34 12 76 mont i co l a CIS* CIS* (OMO) c c u * NEGATIVE TRANSECT A B Cl Penstemon 44 31 17 procerus (PPR) 1 2 2 INTERSPECIFIC ASSOCIATIONS (continued) C2 01 D2 D3 El E2 91 AOB* Po l y t r i ch im 149 257 172 181 - - 24 73 268 pi I Iferun CCA* CCA** (PPI) CSC** c s c # TVE* AOB* AOB** SMU* CIS** KMY** Potent i I la 551 641 128 341 137 65 207 37 144 d i v e r s i f o l ia CN I ** CN I * (PDI) TVE** CIS* CIS*** CAC* BLA* Potent i I la - - - - 25 40 165 25 96 \" ' v e a AOB* (PNI) Sal ix 73 - 607 n iva l i s CCA* CCA*** (SNI) TVE* T V E * \u00C2\u00BB * CIS* CIS*** CNI*** CCU** 1 23 TRANSECT NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) B Cl C2 01 D2 03 El E2 Fl F2 S e l a g i n e l l a 299 205 62 densa (SOE) CCA** CCA** CCU** SAC* FOV* AOB* CNI* CNI* CIS* 104 CCA* CCU** 1 48 CNI' 49 CCU* AOB* TCE* 268 98 CNI' 296 101 269 CCU* CCU*** CCU* SAC** FOV** AOB* AOB* AOB** CNI** CIS** CIS* TVE* KMY* S iIene acaul is (SAC) 11 7 CIS** SDE* 96 CIS* AOB* CCA* 1 1 3 CCA* 1 31 CCA* 27 68 205 10 86 SDE** OUP* CNI*** CAC*** CNI* CAC** So l idago 69 192 m u l t i r a d i a t a PPI* (SMU) 1 8 1 3 26 146 BLA* 24 1 7 125 S te l I a r i a long I pes (SLO) 99 CNI* CIS** 106 38 CIS** 85 CSC* 1 4 33 198 CAC* 23 1 24 NEGATIVE INTERSPECIFIC ASSOCIATIONS (continued) TRANSECT CI C2 DI D2 03 El E2 Fl F2 Tharinol Ina 777 796 259 451 verm Icul ar Is LLY* SNI * 1 5 (TVE) PDI*** FOV** CSC** PPI* SNI1 CCA** TSP* 7 146 90 38 212 CSC* AOB* SDE** CSC* TSP* PPR* CNA* T r i s e tun 49 66 51 96 11 10 20 17 51 14 117 spicatun CCA* (TSP) TVE* TVE* CIS* Blank 49 20 133 29 178 133 333 265 477 16 219 (BLA) CIS** CIS** CSC* CSC* CSC*** SMJ* KMY*** PDI* CCA** 125 chorophaea, and Taraxacum ceratophorum. Negative associations have been grouped into the same five categories used for p o s i t i v e associations. 1) Community and Aspect Relationships: The vast majority of negative associations showed no rel a t i o n s h i p to s p e c i f i c community type, aspect, or the r e l a t i v e abundances of the species involved. Examples include the associations of Arenaria obtusiloba with Cladonia sp. (groups D1, D3, E2, and F2), and with Selaginella densa (groups B, D3, E2, F1, and F2); and the association of Silene acaulis with Cornicularia aculeata (groups E2 and F2). Associations existing each time a species-pair occurs together are again limited to very rare species. For example, Salix n i v a l i s , present in two data sets only, i s associated both times with Carex capitata, Thamnolina vermicular i s , and Cetraria i s l a n d i c a . Low counts (16 or less contacts) for at least one member of the following species-pairs occurred at the only locations where associations between them were not detected: Carex capitata/Kobresia myosuroides, Carex phaeocephala/Carex scirpoidea, and Carex phaeocephala/Cetraria i s l a n d i c a . A small number of negative associations do indicate trends based on certain communities and/or aspects. Seven negative associations are r e s t r i c t e d to vegetation dominated by Carex capitata and Carex scirpoidea, and group F1, where these species are present, but not dominant. Only one of these associations (Oxytropis monticola with Cetraria islandica) i s r e s t r i c t e d to 126 north aspects, and three occur at a l l aspects but N29\u00C2\u00B0E (Festuca ovina/Cladonia sp. and Carex capitata/Polytrichum piliferum) or N58\u00C2\u00B0W (Arenaria obtusiloba/Polytrichum p i l i f e r u m ) . In addition, the association between Kobresia myosuroides and Cladonia sp. occurs only where Kobresia myosuroides i s a dominant or co-dominant, while Carex scirpoidea and Kobresia myosuroides are negatively associated only where they both co-dominate (group D2). A single association (Selaginella densa/Cetraria n i v a l i s ) appears excluded from vegetation dominated solely by Carex sc i rpoidea. The occurrence of three negative associations appears related to aspect. Carex scirpoidea and Polytrichum piliferum, and Silene acaulis and Selaginella densa, are associated at north-west aspects only (groups A and E2), while Cetraria n i v a l i s is associated with Ochrolechia upsaliensis in two community types (dominated by Kobresia myosuroides and by Carex scirpoidea) at an aspect of N16\u00C2\u00B0W only (transect E). Many s i g n i f i c a n t negative associations occur only once. For example, Kobresia myosuroides i s associated with bare ground only where i t i s a dominant.species at a north aspect (group E1). Other examples include the association of Carex scirpoidea with Cetraria cucullata (group B), Kobresia myosuroides with Selaginella densa (group C1), and Arenaria obtusiloba with P o t e n t i l l a nivea and Carex nardina (group E2). 2) Associations Between Vascular Species: i) Monocot/Monocot 1 27 Ten percent of the 97 d i f f e r e n t negative plant/plant associations are between two monocot species, with 60% of these occurring a single time. The most frequent are Carex capitata with Carex scirpoidea (4 times), Festuca ovina (4), and Kobresia myosuroides (4). Two monocot species (Carex scirpoidea and Kobresia myosuroides) are negatively associated with bare ground. i i ) Dicot/Dicot Negative association between dicot species i s very rare only 3% of the t o t a l , with each occurring just once. Arenaria obtusiloba i s involved in a l l three of these associations, with Silene acaulis, Penstemon procerus, and P o t e n t i l l a nivea. Only one dicot species (Solidago multiradiata) i s negatively associated with bare ground. i i i ) Monocot/Dicot Seven percent of the negative plant/plant associations occur between monocot/dicot species-pairs, with 71% of these occurring just once. The most frequent are Carex capitata with Silene acaulis (3 times) and with Salix n i v a l i s (2). 3) Associations Between Vascular Species and Lichens, Mosses, or Clubmoss: The largest number (64%) of negative species associations f a l l into t h i s category, with 42% of these involving monocot species, and 58% involving dicots. Sixty-one percent of 1 28 associations in thi s category occur only once, with the most common occurring 5 times (Arenaria obtusiloba with Selaginella densa). Other frequent associations include Kobresia myosuroides with Cladonia sp. (4 times); Carex scirpoidea with Thamnolina vermicularis (3); Carex capitata with Selaginella densa, Polytrichum piliferum, and Cladonia sp.; and Arenaria obtusiloba with Cladonia sp. (4), Polytrichum p i l i f e r u m (3), and Cornicularia aculeata (3). Twenty-one percent of the associations in this category involve one of the three major dominant species - Carex capitata, Carex scirpoidea, or Kobresia myosuroides. 4) Associations Between Lichens, Mosses, and Clubmoss: Associations in thi s category comprise 15% of the t o t a l number of negative species associations, with a r e l a t i v e l y small percentage (33) occurring only once. Some of the most frequently occurring negative associations f a l l into t h i s category - as was found with p o s i t i v e associations. Examples include the associations of Cetraria cucullata with Selaginella densa (6 times), Cetraria n i v a l i s (5), Cladonia sp. (5), and Ochrolechia upsaliensi s (4); and Cetraria islandica with Cornicularia aculeata (6). Only one lichen species (Cetraria islandica) i s negatively associated with bare ground. 1 29 Constancy Of Int e r s p e c i f i c Associations Constancy of association for a species-pair i s the number of times the association was detected, expressed as a percentage of the t o t a l number of times an association was possible ( i . e . , the two species must occur in the same data set). The constancy of s i g n i f i c a n t positive (Table VII) and s i g n i f i c a n t negative (Table VIII) associations are presented as a summary of Tables V and VI, respectively. Unique and common associations are readily i d e n t i f i e d with constancy data. Constancy values of 50% or more are often limited to rare species present in only 1 or 2 data sets (indicated by * ) , for example, Salix n i v a l i s , Dryas octopetala, Agoseris glauca, and Eriqeron compositus. These species are indicated by a * in Tables VI and VII. Positive associations between more abundant species with constancy values of 50% or greater include Arenaria obtusiloba/Taraxacum ceratophorum (75%); Cornicularia aculeata with Carex nardina (57%) and Selaginella densa (54%); Carex nardina/Selaqinella densa (54%); Carex capitata with Cetraria cucullata (57%), Cetraria i s l a n d i c a (71%), and Cetraria n i v a l i s (57%); Cetraria cucullata with Cetraria islandica (54%) and Kobresia myosuroides (67%); Cetraria i s l a n d i c a with Cetraria n i v a l i s (64%) and Thamnolina vermicular i s (60%); Cladonia sp. with Polytrichum p i l i f e r u m (56%) and Selaginella densa (91%); Penstemon procerus/Carex scirpoidea (67%); Silene acaulis/Festuca ovina (80%); and Selaginella densa with Ochrolechia upsaliensis (64%) and Polytrichum piliferum (67%). Relatively few negative associations have constancy values of 50% or more. These 1 30 T a b l e VII - Constancy of P o s i t i v e A s s o c i a t i o n s Percentage of p o s i t i v e a s s o c i a t i o n s between s p e c i e s p a i r s i n data s e t s where both occur t o g e t h e r . S p e c i e s presen t in <3 data se t s are i n d i c a t e d by a * . * A G L A A L AOB C P U C A L C A N C C A C N A C P H c s c|ioo C B E C C U C I S C N I C M I C C H C L A [WO C A C D E S D I N D L O D P A \u00E2\u0080\u00A2DOC E A U \u00E2\u0080\u00A2 E C O FOV H L Y KMY L V U L L Y L C A O U P O MO P C A PPR P R U POA \u00E2\u0080\u00A2 P P U P J U P P I I P D I \u00E2\u0080\u00A2 P F R P N I \u00E2\u0080\u00A2 SNI S L A SDE S L U S A C SMU S L O T C E T V E T S P B L A 14 45 20 27 33 33 25 27 11 33 25 17 50 50 22 12 75 10 45 27 A C O P B U 33 14 40 57 71 5743 20 25 17 14 57 14 17 33 25 28 14 14 4314 25 54 20 64 20 20 50 452017 9 12 11 20 18 25 67 50 14 28 38 20 67 50 36 18 22 9 11 33 14 22 18 36 20 30 405611 50 25 12 12 50 14 to 50 17 1791 54 50 38 17 17 50 17 50 33 11 22 12 33 100 50C0 tD 30 33 25 14 33 28 X 6 0 50 44 64 20 14 8011 11 50 67 22 17 K>14 36 20 12 20 17 C C C C C C C C C C C C C C D D D D D E E F A A C N P S B C I N M C L A E I L P O A C O L N A A H C E U S I I H A C S N O A C U O V * * 38 28 14 12 12 50 30 20 50 50 25 H K L L M V Y Y U 22 '7 22 20 50 5025 18 12 12 30 _20_ 10 L L O O P P P P P P P P P P S S S S S S S T T T B L C U M C P R O P j P D F N N L D L A M L C V S L Y A P O A R U A U U I I R l I A E U C U O E E P A 131 Table VIII - Constancy of Negative Associations Percentage of negative associations between species pairs in data sets where both occur together. Species present in <3 data sets are indicated by a *. * A G L A A A O B C P U C A L C A N C C A C N A C P H C S C C B E C C U C I S CN I C M I C C H C L A C A C D E S 0 1 N D L O D P A \u00E2\u0080\u00A2 DOC E A U t EC O F O V H L Y KMY L V U L L Y L C A O U O MO| P C A P P R P R U P O A \u00E2\u0080\u00A2 P P U P J U P P I P D I PFR P N I S N I S L A S D E S L U S A C S M U S L O T C E T V El T S P| B L A 14 14 36 27 17 17 33 17 45 10 40 43 33 14 9 14 33 9 25 43 14 45 45 9 18 54 5714 75 14 27 9 67 2211 36 2718 12 25 25 4314 22 100 43 43 14 14 14 14 11 11 18 18 50C050 542745 17 9 9 25 18 17 17 30 27 20 2512 9 18 20 12 10 17 11 10 100 20 25 10 17 11 20 A A C C C C C C C C C C C C C C C D D D D D E E F H K L L L O O P P P P P P P P P P S S S S S S S T T T B f n M ? M C N P ; ? B C I N M C L A E I L P O A C O L MV L C U M C P R O PJ P D F N N L D L A M L C V S L L B U L N A A H C E U S I I H A C S N O A C U O V Y Y U Y A P O A R U A U U I I R | I A E U C U O E E P A 132 include Cornicularia aculeata/Cetraria isl a n d i c a (54%); Carex capitata with Festuca ovina (57%) and with Kobresia myosuroides (75%); Cetraria cucullata/Selaqinella densa (54%); and Kobresia myosuroides/Cladonia sp. (67%). A number of species-pairs are p o s i t i v e l y associated in some data sets and negatively associated in others (Table IX). In the majority of cases, only single associations of one or both types occur. The vascular species, Arenaria obtusiloba and Carex capitata are involved in the largest number of these s i t u a t i o n s . Species Ordinations As a l l forms of pattern, including i n t e r s p e c i f i c association, are dependent on the scale of investigation, a consideration of species associations at the le v e l of the quadrat (20 X 50 cm) seems useful for comparative purposes. PCA and RA were used to ordinate species at this scale, in an attempt to i l l u s t r a t e s i m i l a r i t i e s between species on the basis of co-occurrence within quadrats. I n i t i a l l y , species were ordinated using percentage cover data, which yielded very l i t t l e useful information on the associations between them. As these analyses summarize the range of data v a r i a t i o n , rare species with l i t t l e difference in percentage cover values tend to group together, and more abundant species, with greater cover v a r i a t i o n , appear outlying. In addition, these abundant species are widely separated in the scatter plots, even when present in a l l quadrats, due to cover variation differences. This effect was somewhat more evident with PCA, than with RA. Percentage 1 33 Table IX - Species Pairs Associated Both P o s i t i v e l y and Negatively in Different Vegetation Groups SPECIES ASSOCIATION GROUP Arenaria Carex + B obtusiloba nardina - E2 Kobresia + F1 ;myosuroides - E1 P o t e n t i l l a + D2 nivea - E2 Thamnolina + B vermicularis - E1 Cornicularia + C1 aculeata - A,F1,F2 Carex Carex + F1 capitata scirpoidea - A,B,F2 Lupinus + F2 l y a l l i i - C1 Polytrichum + E1 piliferum - A,B,F2 Cornicularia + F2 aculeata - Cl Thamnolina + C1 vermicularis - C2 Cetraria P o t e n t i l l a + F1 n i v a l i s d i v e r s i f o l i a - A,B Polytrichum + A,E2 pil i f e r u m - F2 Thamnolina Polytrichum + C2,F2 vermicularis p i l i f e r u m - A Selaginella + A,C1 densa - E2 Kobresia Bare ground + F1 myosuroides - E1 134 cover values were then converted to presence/absence data in an attempt to overcome these cover variation d i f f i c u l t i e s . PCA and RA of presence/absence data separated rarer species from more abundant ones, with this effect only s l i g h t l y minimized when species of <5 occurrences were removed. Although species present in a l l quadrats appeared close together in the scatter plots, so did rare species with only absences in common. As well, placement c r i t e r i a for rare and r e l a t i v e l y common species depended more on the t o t a l number of presences and absences shared, than on co-occurrence in part i c u l a r quadrats. Although these analyses were less than sat i s f a c t o r y to i l l u s t r a t e association at the scale of the quadrat, one major point has been emphasized. The grouping of common species due to their presence in most quadrats provides a number of examples of large scale positive associations which are not present at a smaller scale of 2 cm. .- For example, Carex scirpoidea i s negatively associated at 2 cm with i t s co-dominant, Carex capitata in groups A, B, and F2, although both species are present in each sampled quadrat in these groups, and are therefore p o s i t i v e l y associated at thi s scale. Other examples include Cornicularia aculeata/Cetraria i s l a n d i c a , Carex capitata/Festuca ovina, and Cetraria cucullata/Cetraria n i v a l i s - a l l negatively associated at 2 cm and p o s i t i v e l y associated in 20 X 50 cm quadrats. It seems that even r e l a t i v e l y small quadrats tend to give spurious associations compared to those detected at the scale of the individual plant. 135 SOILS Morphology Alpine Dystric Brunisol s o i l s within the study area were described in each vegetation grouping. P r o f i l e descriptions were very similar between s i t e s . The following p r o f i l e of transect A i s t y p i c a l : Horizon Description A 0-14 cm; color (dry) dark brown (1OYR 3/3), (wet) very dark brown (1OYR 2/2); loamy sand, gravel 1-2 cm in diameter, <5%; weak, amorphous structure; f r i a b l e ; p l e n t i f u l fine to medium roots; strongly acid (pH 5.2); abrupt, irregular boundary. B 14-37+ cm; color (dry) dark yellowish brown (10YR 4/4), (wet) dark yellowish brown (1OYR 3/4); loamy sand, gravel (angular) 2-5 cm in diameter, 25%; weak, amorphous structure; f r i a b l e ; abundant fine and very fine roots; strongly acid (pH 5.2). The major rooting depth in these s o i l s ranged from 0 to 18-28 cm, with the majority of roots occurring 0-15 cm below the surface. Physical And Chemical Properties Physical and chemical s o i l properties were determined within the 11 vegetation groups previously described (Table X). A l l p r o f i l e s are strongly acid (pH 4.8-5.6), and pH values may increase or decrease with depth. No relationship between pH and vegetation type was observed. A l l s o i l s are coarse textured, and range from sandy loam to sand, with loamy sand predominating. Organic matter is highest in the A horizon and decreases with depth for a l l p r o f i l e s . TABLE X - PHYSICAL AND CHEMICAL PROPERTIES FROM SOIL PROFILES WITHIN 11 VEGETATION GROUPS. L/S AND S/L INDICATE LOAMY SAND AND SANDY LOAM, RESPECTIVELY. V E G - TEXTURE-2 mm (%) TEXTURE ORGANIC TOTAL A V A I L . EXCHANGEABLE CATIONS TOTAL CATION GROUP HORIZON pH 1%) (II {%T GRAVEL CLASS MATTER N P (meq/100g) EXCHANGE CAPACITY SAND SILT CLAY {%) {%) p p m K Mg Ca (meq/lOOg) A A 0- l4cm 5.2 79 18 3 B 14-37+ 5.2 85 13 2 B A 0-10cm 5.1 84 13 3 B 10-41+ 5.1 88 9 3 C1 A 0-14cm 5.0 80 15 4 B 14-35+ 5-3 69 26 5 C2 A 0-17cm 5.3 84 14 2 B 17-30+ 4.9 80 15 4 D1 A 0- l4cm 5.4 70 27 3 B 14-30+ 5.0 82 15 3 D2 A 0-13cm 5.4 78 21 1 B 13-35+ 5.6 75 21 4 D3 A 0-12cm 4 . 8 86 11 3 B 12-30+ 5.3 83 15 2 E1 A 0-15cm 5 .3 82 16 2 B 15-35+ 5.2 88 10 2 E2 A 0-15cm 5.2 81 15 4 B 15-35+ 5.3 84 13 3 F1 A 0-17cm 4 . 8 83 13 4 B 17-30+ 5 .0 65 30 4 F2 A 0-15cm 5.1 80 16 4 B 15-35+ 4.9 88 11 1 53 L/S 10 .7 \u00E2\u0080\u00A2 32 11.1 52 L/S 5.8 .21 2 0 . 4 58 L/S 13 .0 .46 1 3 . 6 52 SAND 5.2 .22 10 .4 54 L/S 6 .6 .24 12 .4 49 S/L 1.7 .06 3 1 . 9 31 L/S 8 .7 .32 9 .4 33 L/S 2 .3 .13 10 .2 28 S/L 11 .3 .49 7.4 26 L/S 2.1 .12 7 .8 60 L/S 10 .3 .54 6 . 8 44 L/S 4 .9 .29 10 .4 32 L/S 8 .0 .31 1 0 . 9 35 L/S 4 . 7 .14 19.2 43 L/S 9 .6 .33 10.1 44 SAND 1.5 .08 1 2 . 7 46 L/S 7 .7 \u00E2\u0080\u00A2 32 8 .6 40 L/S 3.8 .10 18 .2 29 L/S 6 .2 \u00E2\u0080\u00A2 23 1 0 . 0 21 S/L 2.1 .08 19-3 42 L/S 1 0 . 0 .32 17 .4 60 SAND 5.0 .20 2 8 . 0 . 19 .63 3.92 2 0 . 8 .09 .26 1.69 1 6 . 5 .44 .98 5.07 2 5 . 9 .09 \u00E2\u0080\u00A2 29 1.88 1 7 . 9 .16 .35 1.74 1 6 . 0 .11 \u00E2\u0080\u00A2 31 1.36 7 .8 .22 1.02 4 .82 1 8 . 0 .10 . 17 .70 1 2 . 0 .20 1.62 7.46 2 7 . 4 .08 .17 1 .22 1 0 . 4 .23 .98 6 .60 3 0 . 9 .14 .66 4 . 8 0 2 1 . 5 . 12 \u00E2\u0080\u00A2 52 2 .70 21 .5 \u00E2\u0080\u00A2 19 .46 2 .30 1 5 . 2 .24 .69 5.72 2 3 . 6 .06 .14 1 .26 7 .3 .25 . 9 8 5 .90 21 .5 .06 . 20 1.35 1 0 . 8 .14 \u00E2\u0080\u00A2 30 2 .29 2 0 . 7 .11 .06 .60 8 . 9 .12 .33 2 .02 2 1 . 7 .09 .20 1.43 1 4 . 7 137 Total nitrogen, exchangeable cations, and t o t a l cation exchange capacity appear correlated with organic matter and decrease with depth - often substantially. Values for calcium are r e l a t i v e l y high - p a r t i c u l a r l y in the A horizon of vegetation groups D1 and D2 (7.46 and 6.60 meq/100 g, respectively) compared to the value for group D3 (2.70 meq/100 g) at the same aspect. Magnesium i s also comparatively high in the A horizon of D1 (1.62 meq/100 g), as is t o t a l cation exchange capacity in D1 (27.4 meq/100 g) and D2 (30.9 meq/100 g). In contrast to other analyzed minerals, phosphorus increases with depth. P a r t i c u l a r l y high values for phosphorus were detected in the B horizons of group C1 (31.9 ppm), and F2 (28 ppm). Pri n c i p a l Components Analysis: Physical and chemical s o i l properties of the 11 vegetation groups previously outlined were analyzed with centered and standardized PCA (Appendix D). Values for A and B horizons were analyzed separately, with the f i r s t two axes of each ordination accounting for 68% and 75% of the t o t a l v a r i a t i o n , respectively. Three vegetation groups, B, D1, and D2, appear outlying from the main point cluster after analysis of A horizon values (Appendix D). This i s l i k e l y due to the r e l a t i v e l y high amounts of exchangeable cations and t o t a l cation exchange capacity in these samples (Table X). Group D2 appeared outlying after analysis of B horizon data as well, although groups B and D1 occurred within the main point c l u s t e r . F i r s t axis eigenvectors corresponding to A horizon values for sand, clay, and phosphorus have similar negative values, as 138 do eigenvectors corresponding to B horizon values for s i l t , clay, and phosphorus (Appendix D). This indicates that these parameters tend to vary together, due to interdependency or external agents. CLIMATE Mesoclimate Mesoclimate of Lakeview Mountain was monitored with three weather stations from June 20 to September 6, 1980 (Table XI). Mean da i l y temperatures were very similar between stations and increased u n t i l the July 21-31 period (mean d a i l y max. 18\u00C2\u00B0C), and subsequently decreased. Mean da i l y temperatures of 2-6\u00C2\u00B0C were common, with a mean dai l y minimum of -3.4\u00C2\u00B0C recorded. Wind speed was s l i g h t l y higher at station 1 than at station 2, and mean values ranged from 7.3-20.5 km/hr for both s i t e s . Relative humidity was also increased at station 2, compared to 1 and 3. P r e c i p i t a t i o n was very low throughout the time period measured, with an accumulation of only 2.84 cm. Microclimate Temperature p r o f i l e s for the 1980 growing season show the same general patterns for a l l 11 vegetation groups (Fig. 32). As the actual dates on which readings were taken vary, not a l l graphs are d i r e c t l y comparable. Vegetation groups within a given transect were measured on the same days, as were transects E and F (with the exception of the July 22 and 23 readings, respectively). A l l transects have several reading dates in common. The fluctuations in a i r temperature maxima over the 139 Table XI - Mesoclimatic Data For Three Weather Stations, 1: S84\u00C2\u00B0W, 2481 m; 2: S2\u00C2\u00B0E, 2402 m; and 3: N29\u00C2\u00B0E, 2475 m. TEMPERATURE \u00C2\u00B0C WIND km/hr HUMIDITY DATE STATION MEAN MEAN MEAN % PPT cm 1980 DAILY DAILY DAILY MEAN RECORD. MEAN (60 cm) MIN. MAX. MAX. DAILY 20/6-30/6 1 2 3 \u00E2\u0080\u00A21 .7 \u00E2\u0080\u00A22.2 \u00E2\u0080\u00A21.0 2.6 2.9 3.1 6.9 6.6 7.6 16.5 11.0 31.3 13.8 75 83 77 0.70 1/7-10/7 1 2 3 1 .2 0.4 2.0 5.4 5.1 6.3 11.4 11.2 11.4 10.0 11.2 14.6 18.4 66 71 64 0.43 1 1/7-20/7 1 2 3 0.5 0 1 .7 4.3 4.1 5.4 9.9 9.4 10.4 13.7 9.5 24.7 16.8 78 84 79 0.63 21/7-31/7 1 2 3 3.7 4.0 5.0 9, 10, 1 1 , 16, 18, 17, 14.2 11.0 19.5 15.8 52 64 54 0.01 1/8-10/8 1 2 3 0.3 0 1.0 5.2 5. 1 6.2 10, 1 1 , 10, 7.3 8.5 13.4 15.8 75 78 74 0.21 11/8-20/8 1 2 3 1 .2 0.8 2.2 0 0 9 10 10 10, 10.1 9.5 17.8 14.8 79 82 78 0.66 21/8-31/8 1 2 3 \u00E2\u0080\u00A21.9 \u00E2\u0080\u00A23.4 \u00E2\u0080\u00A21.2 2, 2 3, 8, 8, 8, 11.8 8.5 20.6 11.3 66 70 65 0.04 1/9-6/9 0.2 0.8 0.3 4.5 4.8 4.0 10.0 10.3 9.2 20.5 19.6 38.6 26.6 70 72 70 0.16 1 40 Figure 32 - Microclimatic data for 11 vegetation groupings during summer 1980. Air temperature readings taken at +2 cm are indicated by , +10 cm by , and +20 cm by . S o i l p r o f i l e temperatures at -2 cm are distinguished by \u00E2\u0080\u0094 \u00E2\u0080\u0094 , -10 cm by \u00E2\u0080\u0094 \u00E2\u0080\u00A2 \u00E2\u0080\u0094 \u00E2\u0080\u00A2 , and -20 cm by . Readings were taken between 12:00 pm and 4:00 pm and approximate d a i l y maxima. 141 G R O U P A 30i G R O U P a 30-1 2CH G R O U P C J 30-1 20 -10-0 G R O U P C 2 3 0 1 3 0 10 2 0 3 0 10 2 0 3 0 J U N E J U L Y A U G U S T 1 42 GROUP CM 30i 2CH GROUP D3 30 n 2CH 1 4 3 144 1980 growing season are quite dramatic, ranging from 0\u00C2\u00B0C to 24\u00C2\u00B0C, with the lowest temperatures observed near the begining of July and the highest near the end of August or l a t e r . S o i l temperatures are observed to track a i r temperatures, sometimes with a 1 or 2 day lag period. The influence of a i r temperature decreased with increasing s o i l depth and temperatures become generally cooler and more stable. When an extreme drop in a i r temperatures occurs (e.g., 0\u00C2\u00B0C in transect D on July 5, 1980), s o i l temperatures remain 3-8\u00C2\u00B0C warmer. Subsurface s o i l temperatures at a depth of 2 cm are the most widely fluctuating and often surpass the p r e v a i l i n g a i r temperatures. Highs of 24\u00C2\u00B0C were reached at one location (group E2) due to surface heating. It i s interesting to note that subsurface temperatures in Kobresia myosuroides dominated communities are generally cooler than a i r temperatures by at least 3~4\u00C2\u00B0C, while in Carex scirpoidea and Carex scirpoidea/Carex capitata dominated communities at the same aspect, these temperatures are often greater than a i r temperatures. This i s p a r t i c u l a r l y evident in transects E and F. The most southern transect (D) had subsurface temperatures under Kobresia myosuroides vegetation (group D1) equalling or s l i g h t l y greater than a i r temperatures, while t r a n s i t i o n a l and Carex scirpoidea communities (groups D2 and D3) had values often 2-5\u00C2\u00B0C higher than a i r temperatures. Humidity readings were taken concurrently with a i r temperature readings at 2, 10, and 20 cm above the ground surface. On any given day, percent humidity was r e l a t i v e l y 145 constant between transects - r e f l e c t i n g the mesoclimatic humidity status. At any given s i t e , humidity generally increased with proximity to the vegetation cover - a difference averaging 2-5% between 2 and 20 cm above the surface. Complete data for s o i l moisture levels through the 1980 growing season are regrettably not available. Samples col l e c t e d in June and July were weighed in the f i e l d and subsequently stored in p l a s t i c bags at room temperature u n t i l the end of the f i e l d season. Many of the waterproof tags used to identify samples were unreadable by thi s time due to the intense microbial a c t i v i t y afforded by these warm, moist conditions. The few results available indicate that the highest moisture levels were present in A horizon s o i l s ( l i k e l y due to the high amounts of organic matter) and the greatest loss of moisture occurred in the week following snowmelt. No major differences between transects or vegetation groups were d i s c e r n i b l e . 146 V. DISCUSSION This study has examined selected alpine plant communities of Lakeview Mountain, as well as the corresponding abi o t i c factors of s o i l s and microclimate. I n t e r s p e c i f i c associations in each community and sampled s i t e have been a major focus, with phenological patterns also measured. This discussion w i l l consider various aspects of the vegetation, beginning with communities and associated ab i o t i c parameters, then phenology, and, f i n a l l y , i n t e r s p e c i f i c associations. S o i l s and microclimatic data w i l l then b r i e f l y be discussed. COMMUNITIES The most extensive communities or vegetation types with early snowmelt in the study area were sampled. Subsequent analysis of percentage cover data revealed three major community types. These were dominated by either Kobresia myosuroides, Carex scirpoidea (with one t r a n s i t i o n a l area dominated by both Kobresia myosuroides and Carex scirpoidea), or by Carex sc i rpoidea and Carex capitata (with Salix n i v a l i s as an additional dominant at one s i t e ) . Communities dominated by both Carex capitata and Carex scirpoidea were the most common type. Multivariate analyses of composite data from a l l six transects (Figs. 10-13) indicates the high degree of compositional s i m i l a r i t y between d i f f e r e n t stands of the same community, although some v a r i a b i l i t y i s evident. In other words, no sample groups occur which would correspond to individual sampled transects. Samples dominated solely by Carex scirpoidea are an 147 exception, and some separation of groups D3 and E2 occurs in the ordination scatter p l o t s . This i s possibly due to the higher cover of Cornicularia aculeata and Silene acaulis, higher t o t a l plant cover, and greater species richness in E2. None of the dominants in the sampled communities have a conspicuous associated f l o r a , although species abundances and ove r a l l species richness do change. Average species richness i s lowest in Kobresia myosuroides communities (29 species), compared to the remaining communities, which have similar numbers of species (mean 42). The dense, tussock-forming growth form of Kobresia myosuroides may r e s t r i c t the a b i l i t y of other species to colonize a s i t e . The d i s t r i b u t i o n of these communities has no evident c o r r e l a t i o n with aspect. This i s possibly because of the moderate slopes (7-16%) of sampled transects. As well, community d i s t r i b u t i o n appears to have l i t t l e r e lationship with measured s o i l parameters. S o i l s from each vegetation group were analyzed for a number of physical and chemical properties. PCA of A horizon data indicates three vegetation groups, B, D1, and D2, which are outlying from the main point cluster due to r e l a t i v e l y high values for exchangeable cations and t o t a l cation exchange capacity. Each of these three groups, however, represents a d i f f e r e n t community type, as do outlying groups in the analysis of B horizon data. High levels of available phosphorus occurred within the B horizons of two s i t e s : one dominated by Carex scirpoidea and Carex capitata alone (group F2), and one with the additional dominant, Salix n i v a l i s (C1). 1 48 The reason for these differences i s not apparent at the present t ime. L i t t l e relationship between community type and climatic factors were detected. Air temperatures at both the meso and microclimate scale varied only s l i g h t l y between s i t e s , with no aspect d i s t i n c t i o n s . Subsurface s o i l temperatures (2 cm depth) are an exception, and were generally 3-4\u00C2\u00B0C cooler than a i r temperatures in Kobresia myosuroides communities. Temperatures at a depth of 2 cm were often greater than pre v a i l i n g a i r temperatures in the remaining sampled communities. The Kobresia myosuroides community at S2\u00C2\u00B0E had subsurface temperatures r e l a t i v e l y higher than at other aspects of t h i s community, although s t i l l much lower than in the adjacent Carex sc irpoidea community. The high insulative capacity of the dense Kobresia myosuroides growth form i s a l i k e l y causal factor. Patterns of wind speed and humidity were e s s e n t i a l l y uniform over the study area. The d i s t r i b u t i o n of communities within the study s i t e appears to have l i t t l e r e l a t i o n s h i p to the aspect, s o i l , and climatic factors measured. This contrasts with previous studies in similar environments. For example, B e l l (1973) and Douglas and B l i s s (1977) reported that Kobresia myosuroides w i l l grow only on wind swept s i t e s that are e s s e n t i a l l y snowfree in winter, however, in t h i s study, a l l communities (including Kobresia myosuroides) became snowfree at approximately the same time in 1980 (June 18-20), were uniformly covered with snow before t h i s time, and were not p a r t i c u l a r l y wind swept. Douglas 1 49 and B l i s s (1977), also reported that Carex capitata dominated communities occur on snowbed s i t e s with low snow accumulation and moist s o i l s in the eastern North Cascades, while Carex scirpoidea dominates on dry, well-drained slopes and becomes snowfree e a r l i e r . These environmental bases for community d i s t r i b u t i o n were not substantiated in t h i s study. The p a r t i c u l a r environmental requirements reported by Douglas and B l i s s (1977) are d i f f i c u l t to reconcile, e s p e c i a l l y since Carex scirpoidea and Carex capitata are often co-dominants in the same community. Major (1951) has stated that the vegetation of a region i s a function of mesoclimate, parent materials, topography, biota, and time - the same factors Jenny (1941) related to s o i l properties, and a rather r e s t r i c t e d version of B i l l i n g s (1952). Evidence presently available indicates that the a b i o t i c variables l i s t e d by Major (1951) are e s s e n t i a l l y constant within the study area, with the exception of higher amounts of certain s o i l nutrients at a few s i t e s . As d i f f e r e n t community types occurred at each of these s i t e s , nutrient differences at the scale measured appear to have l i t t l e influence on the d i s t r i b u t i o n of these plant communities. It i s therefore appropriate to consider the remaining b i o t i c factors, which include neighbour relationships (considered in this study), predator/prey interactions, and grazing. Elements of chance (seed d i s p e r s a l , germination, establishment, e t c . ) , l o c a l disturbance, and micro-scale differences in s o i l nutrients may also be important, but are outside the scope of the present study. 150 PHENOLOGY Alpine plants tend to flower and go through other phenological stages very quickly ( B l i s s 1971), aided by the almost universal production of overwintering f l o r a l primordia (Mark 1965, 1970; B i l l i n g s 1974b). I n i t i a t i o n of growth often occurs before the winter snow cover has completely melted, at or near freezing temperatures ( B i l l i n g s and B l i s s 1959, Mooney and B i l l i n g s 1961). In the present study, Draba incerta, D. paysonii, and D. lonchocarpa begin growth before snowmelt, and t h i s may be responsible for their rapid flowering. Most other species, however, flowered 15-40 days after snow release, s l i g h t l y l a t e r than the average reported by B i l l i n g s (1974b) for alpine species in general (10-20 days) and by Douglas and B l i s s (1977) for western Cascade alpine species (14-20 days). The period from f l o r a l expansion to seed dispersal in this study (28-70 days) i s less r e s t r i c t e d than the period previously reported for most alpine species (28-35 days) (Holway and Ward 1965) and also for western Cascade alpine species (18-44 days) (Douglas and B l i s s 1977). The r e l a t i v e l y early snowmelt and subsequently longer growing season of the eastern Cascade alpine, compared to the western Cascades and other alpine areas, may have some influence on these discrepancies. The degree of snow accumulation and time of melt i s largely responsible for reported variations in alpine phenology (Bliss 1956, Holway and Ward 1963, 1965; Mark 1970). In this study, however, 151 phenological differences are due to other factors, as a l l s i t e s became snowfree at approximately the same time. The phenological progression of a species may be influenced by the community type in which i t i s resident. For example, a number of species (e.g., Carex sc i rpoidea, Carex nardina, P o t e n t i l l a d i v e r s i f o l i a ) flower later (10-20 days) and have other phenological stages s i m i l a r l y delayed in vegetation dominated by Kobresia myosuroides, when compared to Carex scirpoidea, or Carex scirpoidea/Carex capitata communities at the same aspect. The identity of these species often varies between s i t e s (e.g., Senecio lugens in transect E, Cerastium beeringianum in transect F). A similar phenological delay was observed for some species within communities dominated by Carex scirpoidea and Carex capitata, when compared to 'pure' Carex scirpoidea communities. These two community types were not sampled at the same aspect, although group E2 (N16\u00C2\u00B0W) and C2 (N29\u00C2\u00B0E) are both north facing. Species flowering l a t e r in the Carex sc irpoidea/Carex capitata dominated vegetation of C2 include Cerastium beeringianum and P o t e n t i l l a d i v e r s i f o l i a (10 days l a t e r ) , and Carex nardina and Carex scirpoidea (20 days l a t e r ) . The l a t t e r dominant species also flowers comparatively la t e r in the remaining Carex sc irpoidea/Carex capitata communities as well. The phenology of species within t h i s community type remained constant where Salix n i v a l i s was an additional dominant (group C1). While aspect appears to have l i t t l e influence on the d i s t r i b u t i o n of communities, i t does, in some cases, influence 152 the timing of phenological stages. A number of species tend to flower e a r l i e r in south facing communities. These species often d i f f e r between community types, although P o t e n t i l l a d i v e r s i f o l i a and Silene acaulis consistently flower and/or f r u i t 4-12 days e a r l i e r at the most southerly aspect sampled for a p a r t i c u l a r community. Other species such as Carex capitata show l i t t l e phenological v ariation due to aspect. Relationships between plant phenology and i n t e r s p e c i f i c association w i l l be considered in the following section, as w i l l other potential association-generating factors. The possible role of species interactions in determining community d i s t r i b u t i o n and structure w i l l also be discussed. INTERSPECIFIC ASSOCIATIONS Small scale patterns in the form of s i g n i f i c a n t associations between species pairs were detected in a l l communities sampled. A t o t a l of 182 d i f f e r e n t s i g n i f i c a n t positive associations and 103 d i f f e r e n t s i g n i f i c a n t negative associations were found. Of the species sampled, 88% had at least one association in one vegetation group. The t o t a l number of associations, however, comprises only 6.8% of a l l possible species-pair combinations (summed over a l l vegetation groups). Associations varied considerably between and within communities. The associations are probably quite stable ( i . e . , p e r s i s t e n t ) , due to the age of these communities and the slow rate of vegetative spread c h a r a c t e r i s t i c of alpine plants ( B i l l i n g s 1974a, B e l l and B l i s s 1979). 153 The intensity of patterning at thi s scale i s rather remarkable considering previous views held by ecologists (Savile 1960, B l i s s 1962, Whittaker 1975), who suggested that species within a r c t i c and alpine communities are e s s e n t i a l l y random in their d i s t r i b u t i o n . Clearly, i t i s not possible to make conclusive statements about the processes generating these patterns from associations alone - controlled experimental procedures are necessary for d e f i n i t i v e interpretations. Associations do, however, present some preliminary implications. A p o s i t i v e association indicates that two species are often physical neighbours and p o t e n t i a l l y in each others sphere of influence. Positive association has been equated to the term 'cohabitation', by Harper et a_l. (1961), which i s defined as a proximity such that interaction between the two species i s considered p l a u s i b l e . This suggests a sharing of habitat or resources (Werner 1979). Coexistence i s a similar term, but implies continuous interaction between species (Aarssen 1983). Co-occurrence, is defined by Werner (1979), as a mutual presence of species only, and w i l l be used in thi s thesis as no a p r i o r i assumptions based on proximity alone are implied. Negative associations indicate a frequent s p a t i a l separation of two species with a consequent infrequency of potential interactions. Negative association has often been interpreted as avoidance of interaction (Aarssen 1983), or as a result of past competition (MacArthur 1972, May 1974, Schoener 1975). There i s l i t t l e evidence, however, demonstrating that species divergence has resulted from coevolution of competitors. Observed patterns may 1 54 be explained by a variety of alternate processes, such as predation, response to disturbance or climatic fluctuations, preadaptation to d i f f e r i n g resource l e v e l s , d i f f e r e n t i a l tolerance of environmental extremes, etc. (Harper 1969; Connell 1975, 1980; Wiens 1977). Certain associations suggest, by their very nature, potential c a u s a l i t i e s , although clear-cut explanations based solely on sampling data are not possible. The i d e n t i f i c a t i o n of possible processes or mechanisms creating and/or maintaining associations w i l l lead, ultimately, to the erection of new hypotheses. Positive and negative associations at a given s i t e may be c o l l e c t i v e l y due to a wide variety of d i f f e r e n t factors and each species pair must be considered separately. Possible Mechanisms Generating Positive Association 1. Niche D i f f e r e n t i a t i o n : Species may have s u f f i c i e n t differences in their ecology ( i . e . , separation on one or more niche dimensions) which allow them to co-occur. This i s similar to the term \"ecological combining a b i l i t y \" used by Harper (1964, 1967, 1977b) in discussions of coexistence. Niche separation functions in reducing competition and increasing the individual productivity of two co-occurring species, although niche overlap does not necessarily confer competition i f resources are p l e n t i f u l (Pianka 1979). Resource partioning among a wide variety of co-occurring species has been reviewed by MacArthur (1972), Schoener (1974a,b), and Pianka (1976). Definite ecological 155 differences have been reported for v i r t u a l l y a l l co-occurring species studied, and include differences in nutrient requirements, use of space, and temporal a c t i v i t y (Pianka 1979). Niche complementarity often occurs between d i f f e r e n t species, and may result in a given population suppressing i t s own growth more than the growth of other species (Cole 1960). Separation can occur on a wide variety of niche dimensions, which may be morphological or physiological in nature. Several p o s s i b i l i t i e s within the alpine zone are considered here, a) Temporal Partioning: Asynchronous phenologies (e.g., timing of flowering, f r u i t i n g , etc.) may allow species to make their greatest resource demands on the environment at d i f f e r e n t times allowing co-occurrence. Concurrent differences in the seasonality of growth has been reported for p o s i t i v e l y associated grassland species (Turkington and Harper 1979c, Fowler and Antonovics 1981). As well, phenological v a r i a t i o n may account for the co-occurrence of species in semi-desert (Bykov 1974), t r o p i c a l rainforest (Medway 1972, Frankie et a l . 1974), deciduous woodland (Grubb 1977), and understory herb communities (Bratton 1976). The c h a r a c t e r i s t i c late maturation of polyploids may provide the niche separation necessary for the co-occurrence of i n t r a s p e c i f i c individuals with d i f f e r i n g ploidy levels (Lewis 1976). The present study has provided l i t t l e evidence that positive associations among alpine species are maintained by temporal partioning. A few isolated p o s s i b i l i t i e s do occur, however. For example, Solidago multiradiata has 156 l i t t l e or no overlap of flowering period with positive associates. A similar separation of flowering times was observed for the p o s i t i v e l y associated Arenaria obtusiloba and Draba lonchocarpa (although other Draba species with congruent phenologies are not p o s i t i v e l y associated with Arenaria obtusiloba). As the alpine growing season is very short, l i t t l e opportunity for major phenological differences ex i s t s , b) Morphology: As a large proportion of alpine plant biomass i s underground (B l i s s 1966, Webber 1974, Webber and May 1977), differences in root morphology may be an important factor allowing niche separation of alpine species. D i s s i m i l a r i t i e s in size, shape, arrangement, and depth of roots may result in two species exploiting d i f f e r e n t volumes of s o i l and, concurrently, d i f f e r e n t nutrient and moisture pools, while growing together. This has been postulated for species in old f i e l d s (Wieland and Bazzaz 1975, Parrish and Bazzaz 1976), and pastures (Berendse 1979). In the present study, species with thick, branching taproots such as Arenaria obtusiloba, Oxytropis monticola, and Erigeron aureus are p o s i t i v e l y associated with the fibrous-rooted Festuca ovina at some s i t e s . In addition, the rhizomatous Carex scirpoidea produces fibrous-rooted shoots and is a common positive associate of Arenaria obtusiloba, Oxytropis monticola, P o t e n t i l l a d i v e r s i f o l i a , Silene acaulis, Solidago multiradiata, Penstemon procerus, and Aqoseris glauca - a l l variously taprooted. Many more examples ex i s t . In contrast, very few positive associations occur between s i m i l a r l y fibrous-157 rooted monocots. Niche separation may also occur when differences in alpine f l o r a l morphology allow partioning of s p e c i f i c p o l l i n a t o r s ( B i l l i n g s 1974b, Macior 1974). This i s a strong p o s s i b i l i t y in the alpine zone, where insect-mediated p o l l i n a t i o n i s common (Petersen 1977) and p o l l i n a t o r d i v e r s i t y and abundance i s low (Holway and Ward 1965, Brinck 1974, Moldenke 1976). Although partioning of p o l l i n a t o r s has been reported for plant species in more temperate climates (Reader 1975, Parrish and Bazzaz 1978), no data are available for the contribution of t h i s factor to positive alpine associations, c) Physiology: It seems very l i k e l y that physiological v a r i a t i o n between alpine species may provide an opportunity for co-occurrence, as has been suggested for lowland species. For example, co-dominant annuals in a successional f i e l d were found to d i f f e r in their d a i l y patterns of leaf water p o t e n t i a l , l i g h t saturation points, and rates of photosynthesis (Wieland and Bazzaz 1975). In addition, d i f f e r e n t nutrient l e v e l s in co-occurring forest species, including species in the herb layer (Siccama et. a l . 1970), have been postulated as expressions of niche d i f f e r e n t i a t i o n , due to differences in nutrient uptake rates, use of s o i l space, or in the type of nutrient sources exploited (Woodwell 1974, Woodwell et a l . 1975). A substantial amount of physiological variation has been reported for alpine species, resulting in d i f f e r e n t i a l nutrient requirements, rates of uptake, and tissue nutrient l e v e l s 158 (Larcher et a_l. 1975, Rehder 1976), d i s s i m i l a r storage and mobilization rates for carbohydrates and l i p i d s (Mooney and B i l l i n g s 1960, Hadley and B l i s s 1964), and differences in photosynthetic and respiration rates and temperature optimums (Mooney et a l . 1964, B l i s s and Hadley 1964, Scott and B i l l i n g s 1964, Mark 1975). Physiological differences between immediate neighbours in the alpine zone have yet to be studied. 2. Balanced Competitive A b i l i t i e s ; Co-occurrence as the result of niche separation i s a commonly held view (MacArthur 1972, Newman 1982b) and i s a cor o l l a r y of Gause's competitive exclusion p r i n c i p l e (Gause 1934, Hardin 1960), which states,that two species with i d e n t i c a l ecological niches w i l l not coexist. Theoretical conclusions based primarily on competitive exclusion within animal populations in laboratory culture, for example, Paramec ium (Gause 1934), and Drosophila (Ayala et \u00C2\u00A7_1. 1973), may have l i t t l e r e lationship to plants. Plants have the potential for more subtle responses to the considerable niche overlap present between species at a given s i t e . Aarssen (1983) has proposed that selection for a balancing of competitive a b i l i t i e s between species pairs may be common. This would act to reduce i n t r a s p e c i f i c competition among individuals of a strong competitor, and would also prevent competitive exclusion of a s l i g h t l y weaker competitor. Although no di r e c t evidence i s available to substantiate t h i s mechanism in the present study, i t i s a p o s s i b i l i t y , considering the age of these alpine 159 communities and the large number of p o s i t i v e associations detected (79 more positive than negative). 3. Additional Mechanisms: a) Predation: Predation, such as selective grazing, may lead to the suppression of a superior competitor and allow co-occurrence with a weaker competitor (Harper 1969, Grime 1979). At t h i s study s i t e , marmots have been observed to s e l e c t i v e l y graze f l o r a l heads of Oxytropis monticola. Only controlled experiments could help determine i f this contributes to the subordinate community role or positive associations of t h i s species. Specific grazing habits of other animals were not observed. b) Available Nutrients: Three vegetation groups in the study area (B, D1, D2) were found to have r e l a t i v e l y high amounts of exchangeable cations in the A horizon. This indicates large scale differences, as composite samples, taken from various points in each s o i l p i t , were used for nutrient analysis. Trends within the s i g n i f i c a n t p o s i t i v e associations detected do not appear to r e f l e c t these higher nutrient levels, although two exceptions were noted. Carex sc i rpoidea and Solidago multiradiata are p o s i t i v e l y associated in these three vegetation groups only, while the p o s i t i v e association between Kobresia myosuroides and P o t e n t i l l a d i v e r s i f o l i a i s r e s t r i c t e d to two of these groups (D1 and D2). Differences at a small scale (e.g., centimeters) may have a much 160 greater influence on the formation of positive associations. Certain species, through the action of symbionts, may l o c a l l y increase the levels or a v a i l a b i l i t y of nutrients, inducing positive association with other plant species. This could be p a r t i c u l a r l y important in the alpine zone due to the low nutrient status of alpine s o i l s , the slow rate of nutrient absorption and assimilation in alpine species, and the reduced microbial a c t i v i t y present under low s o i l temperatures (Nimlos et a l . 1965, Bamberg and Major 1968, McCown 1975). Nitrogen and phosphorus are the major l i m i t i n g nutrients in alpine species (Rehder 1976a), with a steady decrease of these nutrients occurring in plant tissues over the growing season (Mooney and B i l l i n g s 1961). It i s well known that many legume species have Rhizobium nodules on their roots which f i x atmospheric nitrogen (Corby 1981). Nodules were observed on the roots of Lupinus l y a l l i i and Oxytropis monticola seedlings. These species were r e l a t i v e l y infrequent in the communities sampled and did not have an exceptionally large number of po s i t i v e associations. No negative associations occurred between these and other vascular species, however, with the exception of Lupinus l y a l l i i and Carex capitata in group CI. As Lupinus l y a l l i i i s p o s i t i v e l y , and Carex capitata i s negatively, associated with Salix n i v a l i s in t h i s group, th i s could be a secondary result of the Carex capitata/Salix n i v a l i s negative association. Peltigera canina i s the only lichen containing nitrogen-f i x i n g blue-green algae (Nostoc) present at this study s i t e . 161 This lichen s i g n i f i c a n t l y contributes to nitrogen stores in many tundra communities (Forman and Dowden 1977, Alexander et a l . 1 978). Peltigera canina i s p o s i t i v e l y associated with only 4 d i f f e r e n t species (2 vascular and 2 lichen) and has no negative associations - possibly due to the infrequent occurrence of t h i s species. Blue-green algae such as Nostoc often occur with moss in moist tundra s i t e s (Granhall and Selander 1973, Alexander et a_l. 1978) and s i g n i f i c a n t nitrogen f i x a t i o n has been found even in r e l a t i v e l y dry, meadow si t e s in the tundra (Schell and Alexander 1973). It does not seem l i k e l y that moss species sampled in t h i s study were a f f i l i a t e d with large amounts of blue-green algae, because of the predominance of negative associations between moss and vascular species. Lichens without blue-green a l g a l symbionts have been reported to function more generally as nutrient traps accummulating minerals such as phosphorus and transforming calcium into an available form (Syers and Iskander 1973). Minerals are leached out of l i v i n g lichen t h a l l i and released after lichen decomposition (Milbank and Kershaw 1973). This process may contribute to the frequent p o s i t i v e associations observed between certain vascular species and lichens. As lichens occur at the s o i l surface only, they occupy an environment very d i f f e r e n t from the deep rooting vascular plants. Positive vascular/lichen associations may therefore result where competitive exclusion of other vascular species has occurred, and positive associations between dif f e r e n t lichen species may occur secondarily within such zones of 'vascular 162 exclusion'. Mycorrhizal root infections are found in some tundra species (Haselwandter and Read 1980, Read and Haselwandter 1981) and benefits to the host plant are well known, p a r t i c u l a r l y where nutrient levels are low (Harley 1969, Sanders et a l . 1975). Mycorrhiza may also enhance the nutrient status of neighbouring, non-infected species, through l o c a l increases in soluble nutrients. Mycorrhizal infections (endophytic) have been reported in alpine ericaceous species (Pearson and Read 1973, Haselwandter and Read 1980), in a variety of herbaceous alpine species in Austria (including the genera Silene, P o t e n t i l l a , Carex, Dryas, Arenaria, and Cerastium) (Read and Haselwandter 1981), and in almost a l l a r c t i c and alpine shrub and dwarf Salix species in Alaska (Mi l l e r and Laursen 1978, Laursen and Chmielewski 1980, Linkins and Antibus 1980). Mycorrhizal infection of Salix n i v a l i s may be a factor contributing to the large number of positive vascular associations observed for t h i s species. Only lichens and Carex capitata were negatively associated with Salix n i v a l i s . In addition, increased levels of phosphorus occurred in the B horizon s o i l s of vegetation where Salix n i v a l i s was one of the dominant species. Ectomycorrhizal infections have been reported for Kobresia myosuroides in European alpine areas (Fontana 1963, 1977; Haselwandter and Read 1980; Read and Haselwandter 1981), a species with few positive vascular associations in this study. A highly competitive species may gain the most b e n i f i t from l o c a l increases in nutrients. As well, d i f f e r e n t i a l rates of 1 63 absorption may occur for d i f f e r e n t types of mycorrhizal fungi, although these are not known (Haselwandter and Read 1980). c) Microenvironmental E f f e c t s : Certain species may modify microsite conditions and thereby enhance the growth, and p a r t i c u l a r l y the germination and establishment, of other plant species (Harper 1964) - events which occur infrequently in the alpine ( B i l l i n g s 1974b). This is another possible explanation for the positive associations of Salix n i v a l i s . This species has leaves orientated close to the ground and an open growth form, with 'gaps' of bare s o i l (demonstrated by association analysis (Table 4)) between leaves. This configuration produces a shady micro-environment with r e l a t i v e l y high humidity and moisture l e v e l s , warmer temperatures, and protection from wind. The ubiquitous positive association between Festuca ovina and Silene acaulis may also be due to the protection and warmer temperatures afforded by t h i s cushion species. Seedling and small Festuca ovina individuals were growing within most Silene acaulis plants observed during t h i s study. Seedlings within cushion species such as Silene acaulis and Diapensia lapponica L. have been previously reported (Griggs 1956, B l i s s 1963). The occurrence of moss species in dry s i t e s has also been linked to the microsite conditions produced by the vascular canopy - p a r t i c u l a r l y with respect to reduced water losses (Stoner e_t a l . 1978), and may contribute to pos i t i v e association between mosses and vascular species. A wide variety of possible factors may contribute to pos i t i v e associations between species. As extensive testing of 164 these and other hypotheses i s required before cause and effect relationships can be established, the preceding interpretations are necessarily speculative in nature. Possible Mechanisms Generating Negative Association 1. Morphology: Species with a clumped growth form, such as the dense, tussock-forming Kobresia myosuroides, w i l l have r e l a t i v e l y fewer opportunities to grow next to members of a d i f f e r e n t species than would a species with a more open growth form. This may resu l t in negative associations with species less able to 'combine' with the clumped i n d i v i d u a l . Species with very similar morphologies - p a r t i c u l a r l y with respect to roots - may also be infrequent neighbours. For example, taprooted species rarely form positive associations with each other and occasionally form negative associations (e.g., Arenaria obtusiloba and Silene acaulis in group B). This trend i s also apparent with fibrous-rooted species, such as Festuca ovina and Carex nardina. 2. Abiotic E f f e c t s : Differences in resource requirements and environmental tolerances between species may form the basis for negative association within any given community. Previous workers with low elevation species have reported that microtopography (Struick and Curtis 1962, Bratton 1976), s o i l disturbance ( F i t t e r 1982), s o i l depth (Kershaw 1958), and heterogeneity of 165 s o i l pH (Dowries and Beckwith 1951), and s o i l minerals in grassland (Snaydon 1962), chalk heath (Grubb et a l . 1969), and limestone heath (Etherington 1981) can affect plant d i s t r i b u t i o n over distances as short as 60 cm. In addition, differences in s i t e requirements for seed germination and establishment (Grubb 1977), tolerance of s o i l chemicals, p a r t i c u l a r l y at germination (Williams and Harper 1965, Williams 1969), and nutrient requirements (Harper et a l . 1961), can result in the s p a t i a l separation of species at a given s i t e . The s o i l and climatic parameters sampled in the present study d i f f e r e d l i t t l e between s i t e s , with the exception of higher levels of exchangeable cations in the A horizon of groups B, D1, and D2. These r e l a t i v e l y large scale differences were not r e f l e c t e d in the s i g n i f i c a n t negative associations detected. No negative associations are r e s t r i c t e d to these vegetation groups, or, conversely, conspicuously absent from these groups. There i s , therefore, no indication that increases in nutrient levels at th i s scale reduces the number of negative associations. Investigation at a much finer scale, however, may indicate d i f f e r e n t i a t i o n of these factors at the l e v e l of the individual plant. Negative association may be influenced at t h i s finer scale. 3. Competitive Exclusion: Species or individuals with high competitive a b i l i t i e s may exclude certain other species from th e i r immediate surroundings. A negative association between the stronger and the weaker competitors may then r e s u l t . Past competition cannot be 166 conclusively inferred from negative association alone, however, as other factors may be responsible (Connell 1975, 1980). In extreme cases, species d i v e r s i t y at any p a r t i c u l a r s i t e may be lowered due to competitive exclusion (Grime 1973a). An endless l i s t of physiological and/or morphological characters can confer an increase in r e l a t i v e competitive a b i l i t y for plant species in general. These include such factors as more e f f i c i e n t uptake of nutrients, increased growth rate and size (Black 1960), large root systems and/or associated mycorrhiza, deposition of organic material unfavorable to other species (Grime 1973b), and release of a l l e l o p a t h i c chemicals (Rice 1974). In extreme environments such as the alpine, r e l a t i v e growth rates, seed production, and/or seedling s u r v i v a l , and subsequent competitive a b i l i t y , may be increased for species best able to withstand unfavorable conditions (e.g., drought, freezing, intense U.V., etc.) due to a specialized morphology, p l a s t i c i t y , or general resistance. Kobresia myosuroides i s an extreme example, with high tolerance of both drought and cold (Ehle.ringer and M i l l e r 1975) and a readiness to grow even under subfreezing conditions. Leaf elongation in t h i s species occurs during winter periods near 0\u00C2\u00B0C (Bell and B l i s s 1979). Other herbaceous winter-green species have been reported (Bell 1974), although the growth of most alpine species i s r e s t r i c t e d to temperatures above 0\u00C2\u00B0C (Holway and Ward 1963, B i l l i n g s 1974b). Experimental data on the r e l a t i v e competitive a b i l i t i e s of alpine species i s very limited, although a small number of studies suggest that competition may be a s i g n i f i c a n t factor in t h i s zone. For 167 example, certain rosette species such as Draba cannot grow when heavily shaded ( B i l l i n g s 1974a), Thalspi alpestre L. individuals become larger when growing in i s o l a t i o n (Rochow 1970), and in the Norwegian alpine tundra, only single t i l l e r s of Carex bigelowii Torr. individuals invade each small region of adjacent s o i l (with frequent abortion of newly i n i t i a t e d ramets), which is interpreted as a competition-avoidance strategy (Callaghan 1976). This is in d i r e c t contrast to Grime's (1979) categorization of alpine species as S-strategists. Grime (1979.) states that S-strategists are species able to withstand extreme environmental stress (an anthropomorphic viewpoint), and must necessarily be weak or non-competitors. The primarily vegetative regeneration strategy of alpine plants (as S-s t r a t e g i s t s ) does not, however, preclude the existence of competition. As sampling occurred at a very fine scale (every 2 cm) i n t h i s study, i t i s conceivable that secondary negative associations are generated. For example, species that are negatively associated with Carex capitata often have additional negative associations with various species of lichen. Possibly, these additional negative associations are generated because the lichen species are p o s i t i v e l y associated with Carex capitata. Cole (1957) termed th i s secondary type of association as \" p a r t i a l \" association in a discussion of species co-occurrence within quadrats. 168 Genotypic Response Positive and negative species associations vary considerably between sampled s i t e s in the study area. Species pairs occurring together at a number of s i t e s are rarely associated in a l l of them. As well, only a small number of i n t e r s p e c i f i c associations had any relationship to community or aspect. These data suggest that population d i f f e r e n t i a t i o n of alpine species occurs over very short distances. The genotype or individual and not the taxonomic species may be the c r i t i c a l ecological unit in the alpine zone, as has been argued by Harper (1977a,b, 1982) and Aarssen (1983) for lowland species. Genotypes may form associations with a variety of d i f f e r e n t species, depending more on certain c h a r a c t e r i s t i c s of the genotypes i n i t i a l l y present, and less on the taxonomic or s p e c i f i c i d e n t i t y of that genotype. Fine-scale b i o t i c s p e c i a l i z a t i o n between genotypes of temperate species has been reported by A l l a r d and Adams (1969), Turkington and Harper (1979c), Joy and Laitinen (1980), and Aarssen (1983). In these studies, increased t o t a l y i e l d was obtained from clones of immediate neighbours, compared to non-neighbouring clones of the same two species. Genotypes which have d i f f e r e n t i a t e d as a result of evolutionary co-adaptation may be termed \" b i o t i c ecotypes\" (Aarssen 1983). The importance of genetic differences within a species, including the degree of p l a s t i c i t y (Jacob and Monod 1961), and their relationship to environmental factors (abiotic ecotypes) has long been recognized (Turesson 1922, 1923; Heslop-Harrison 169 1964, Langlet 1971). Alpine ecotypes are common in species with a r c t i c / a l p i n e d i s t r i b u t i o n s , and d i f f e r in physiological factors such as photosynthetic and respiration rates, photosynthetic l i g h t saturation points, metabolic acclimation to temperature, etc. (Mooney and B i l l i n g s 1961, McCown and Tieszen 1972, T r a n q u i l l i n i 1964, Tiezen and Wieland 1975, B i l l i n g s e_t a l . 1971, B i l l i n g s 1974a). D i f f e r e n t i a t i o n of alpine plant populations, attributed to snow cover, temperature, and length of growing season, have been reported on a more l o c a l scale after transplant studies along elevational gradients (Clausen e_t a l . 1948, Ward 1969, Rochow 1970, Pearcy and Ward 1972). On an even f i n e r , microenvironmental scale, ecotypes from a variety of di f f e r e n t habitats in a given area have been reported for tundra species, d i f f e r i n g in phenology (Holway and Ward 1965, May 1976), seed germination requirements (Amen and Bonde 1964), r e l a t i v e rates of seed germination (Sayers and Ward 1966), and competitive a b i l i t i e s (Shaver e_t a_l. 1979). These genetically based differences are attributed exclusively to environmental factors in these studies. The s i t e s p e c i f i c responses (in the form of positive and negative associations) of species in the present study, and the lack of major environmental differences between s i t e s , suggests that b i o t i c s p e c i a l i z a t i o n or interaction between genotypes may also be responsible for population d i f f e r e n t i a t i o n in the alpine zone. The unique selection pressures (e.g., differences in grazing, disturbance, etc.) operating during the history of a si t e w i l l , of course, be influencing factors. Fine scale 170 genetic variation between neighbouring alpine species has yet to be studied experimentally. Dominant Species The v a r i a b i l i t y of species associations between dif f e r e n t sampled stands of the same community or vegetation type has been noted. The s i m i l a r i t y of these stands, however, i s defined c h i e f l y on the basis of the dominant or most abundant species. It i s inferred by the use of the term 'dominant', that the most abundant species also acquire the greatest proportion of resources available to the community (McNaughton and Wolf 1970), and therefore possess the greatest competitive a b i l i t y within that community. Observations of low elevation dominants has led to the suggestion that these species also have broader niches than species with lower biomass and density (Levins 1968, McNaughton and Wolf 1970, Parrish and Bazzaz 1976). It i s very probable that the narrower realized niche of subordinate species i s at least p a r t i a l l y due to the presence of neighbouring dominants. For example, removal of dominant grass species in an old f i e l d increased the net productivity of less abundant species by almost three-fold (Pinder 1975), and a s i m i l a r l y dramatic effect on the growth of sand dune annuals was attributed to neighbouring species (Mack and Harper 1977). The three major dominant species in the present study were observed to have fewer posi t i v e and negative associations than many other less abundant species in the community, although similar numbers of associations were also observed. In 171 addition, most negative associations between vascular plants involve a dominant species. Insight into the r e l a t i v e competitive a b i l i t i e s of these three dominant species may be obtained by examining the i n t e r s p e c i f i c associations and phenology of each under varying conditions. These data suggest a competitive hierarchy of dominant species within the study area, with Kobresia myosuroides as the most competitive, compared to a l l other species, followed by Carex capitata, and f i n a l l y by Carex scirpoidea. This argument w i l l be supported by the following examples: 1) Kobresia myosuroides: No negative associations occur between vascular species in Kobresia myosuroides communities, other than those of the dominant species with Carex capitata, and with Carex scirpoidea, where they co-dominate in group D2. Positive associations between Kobresia myosuroides and vascular species are rare, with lichen associations more common. As well, a r e l a t i v e l y large number (5) of vascular species are p o s i t i v e l y associated with bare ground in the largest data set that Kobresia myosuroides dominates (E1). Kobresia myosuroides dominated vegetation has abrupt t r a n s i t i o n s with other communities, with Kobresia myosuroides as the sole dominant in a l l but extremely rare and l o c a l i z e d instances. The t o t a l number of d i f f e r e n t associations i s low in some Kobresia myosuroides dominated stands, but t h i s i s l i k e l y due to the small number of sampling points in these data sets, as well as the comparatively lower species richness previously 1 72 discussed. The delay of phenological stages for some species within Kobresia myosuroides communities has previously been noted. A consistent lack of negative association i s present between these and the dominant species. Suppression of Carex scirpoidea phenology has been observed at north facing aspects of thi s community. The phenology of Carex capitata, however, remained unchanged in Kobresia myosuroides communities. 2) Carex capitata: This species is present as a co-dominant only at s i t e s also co-dominated by Carex scirpoidea. The vast majority of positive Carex capitata associations involve lichen species, while negative associations with vascular species predominate. Carex capitata i s negatively associated with Carex scirpoidea where they co-dominate (except transect C) and p o s i t i v e l y associated when the two species occur together in Kobresia myosuroides communities. Carex capitata is also strongly negative with Salix n i v a l i s where th i s species in an additional dominant. The l a t e r flowering times of some species in Carex sc i rpoidea/Carex capitata communities, compared to Carex scirpoidea communities, has been noted. Of interest i s the delayed flowering of Carex scirpoidea where i t co-dominates with Carex capitata. 3) Carex scirpoidea: This species has very few associations where i t i s the sole vascular dominant. It has a r e l a t i v e l y larger number in communities co-dominated by Carex scirpoidea and Carex capitata 173 or dominated by Kobresia myosuroides, and associations detected here may be s p e c i f i c a l l y excluded from Carex scirpoidea dominated vegetation, even when the former associate is abundant. On average, less abundant species in Carex scirpoidea communities are involved in more associations than the dominant plant. Carex scirpoidea i s rarely negatively associated with vascular \u00E2\u0080\u00A2 species other than Carex capitata and Kobresia myosuroides, and has no positive lichen associations, in contrast to the other dominant species. These observations suggest that Carex scirpoidea i s the least competitive of the dominant species, as evidenced by the lack of negative association with, and phenological suppression of, subordinate vascular species, as well as the lack of pos i t i v e lichen and moss associations. Kobresia myosuroides i s indicated as the most competitive, due to i t s sole dominant status, as well as the phenological suppression of Carex scirpoidea and other species, and lower species richness in communities i t dominates. Less strongly competitive subordinate species appear to have a greater a b i l i t y to form positive associations than do the dominant plants. It i s interesting that Carex capitata, and p a r t i c u l a r l y Carex scirpoidea, are associated with d i f f e r e n t species, as well as d i f f e r e n t numbers of species, when they are dominants. This is further support for the possible existence of b i o t i c ecotypes on a l o c a l scale, discussed e a r l i e r . Similar negative association between co-dominant species has been reported for o l d - f i e l d annuals and implies niche d i f f e r e n t i a t i o n (Wieland and 174 Bazzaz 1975), due to preadaptation or possibly competitive exclusion (Connell 1975, 1980). It i s also suggested that the r e l a t i v e competitive a b i l i t i e s of these three major dominants may be the c r i t i c a l factor influencing the d i s t r i b u t i o n of communities within the study area. Such large scale patterning was previously attributed e n t i r e l y to ab i o t i c factors in the alpine zone. The degree of competitive dominance i s mediated by the environment, but, in an e s s e n t i a l l y uniform area (as suggested by parameters measured in t h i s study), i n i t i a l establishment (due to chance, available safe s i t e s , bare s o i l , etc.) and' subsequent vegetative spread of dominant species may determine community patterning. Once species are established, l i t t l e chance for germination or invasion by other potential dominants' i s possible - p a r t i c u l a r l y in dense Kobresia myosuroides communities. This has been termed 'premptive competition' or competition for space, by Werner (1979). As the l i k e l i h o o d of death i s generally greatest for any plant during germination and establishment (Harper 1967, Sarukhan and Harper 1973), only a dominant surviving past a certain size w i l l be able to suppress or displace other colonizing species (Connell 1975). The s p a t i a l pattern of dominant species may then determine the presence and placement of other plants (Werner 1979). A large number of morphological and physiological factors can confer r e l a t i v e competitive dominance in a given s i t e and require experimental study for i d e n t i f i c a t i o n . 175 SOILS S o i l s within the study area on Lakeview Mountain have been characterized by van Ryswk (1969) as Alpine Brown with discontinuous ash, following the U.S. c l a s s i f i c a t i o n system (So i l Survey Staff 1975), and by Green and Lord (1979) as Alpine Dystric Brunisols, following the S o i l Survey Committee of Canada (1968). The coarse texture of s o i l in t h i s study area, (sandy loam to sand) is c h a r a c t e r i s t i c of alpine s o i l s (Faust and Nimlos 1968, Sneddon 1969, van Ryswyk 1969, Sneddon et a l . 1972, Luckhurst 1973), as i s the large proportion of gravel and stone (Nimlos et a l . 1965). S o i l s are strongly a c i d i c , with pH values corresponding c l o s e l y to those obtained by van Ryswyk (1969). The ac i d i c nature of other alpine s o i l s has been associated with the presence of volcanic ash (Sneddon 1969) and high lev e l s of organic matter ( B l i s s 1963). Levels of organic matter were high in the study area, p a r t i c u l a r l y in A horizons (2 to 5 times as high as B horizons) and were within the range reported by van Ryswyk (1969) and Douglas and B l i s s (1977) for similar s o i l s within the Cascade alpine zone, although higher values were frequently detected by these authors. Organic matter accumulation i s largely due to low temperatures, which r e s t r i c t oxidation processes (Nimlos and McConnell 1965). Total nitrogen (%) was, on average, within the range reported by van Ryswyk (1969) for discontinuous ash s o i l s , although some values were s l i g h t l y higher. Values for nitrogen and other nutrients (except phosphorus) tend to decrease with 176 depth (in correlation with levels of organic matter) in this study area and in other alpine regions (Nimlos and McConnell 1965, Sneddon et a l . 1972, Knapik et a l . 1973), with ov e r a l l nutrient lev e l s low compared to more temperate regions ( B l i s s 1963, Bockheim 1972, Douglas and B l i s s 1977). Levels of available phosphorus are within the range reported by Douglas and B l i s s (1977) for the western North Cascades, although well below the maximum values published by these authors. In addition, phosphorus increased with depth in the present study, in contrast to the findings of Douglas and B l i s s (1977), but in agreement with other alpine areas (Nimlos and McConnell 1965). Values for exchangeable cations and t o t a l cation exchange capacity were also within the range reported by van Ryswyk (1969) and Douglas and B l i s s (1977). Calcium l e v e l s , however, were comparatively higher ' than in the l a t t e r study. S o i l properties were r e l a t i v e l y constant between sampled s i t e s on Lakeview Mountain. The few differences that were detected have been discussed previously. CLIMATE As previously outlined, mesoclimate (measured at three weather stations) was r e l a t i v e l y constant over the study area during the 1980 growing season (Table 10). Wind speed was comparatively higher at station 1 (above transect C) than at station 2 (below transect D). Microclimatic a i r and s o i l temperature p r o f i l e s also d i f f e r e d l i t t l e between sampled s i t e s , with the exception of the 177 cooler subsurface temperatures (2 cm depth) in Kobresia myosuroides dominated vegetation, possibly due to i t s higher insulative- capacity. Similar temperature monitoring in the western Cascade alpine (Douglas and B l i s s 1977) indicated that subsurface temperatures were usually higher than a i r temperatures in sparsely vegetated areas ( f e l l f i e l d s ) . In addition, increasing vegetation cover was correlated with decreasing temperatures at depths of 2-30 cm by these authors. S o i l temperatures fluctuated with pre v a i l i n g a i r temperatures in the present study, with the steepest gradients between s o i l at depths of 2 cm and 10 cm. This was s i m i l a r l y reported by Douglas and B l i s s (1977). Air and subsurface temperatures reached a recorded maximum of 24\u00C2\u00B0C at one transect (E) and minimum temperatures near 0\u00C2\u00B0C were noted for most s i t e s in early July, 1980. Temperatures tended to increase as the growing season progressed. Much higher maximum subsurface temperatures have been reported previously for subalpine and alpine areas in western North America (35-49\u00C2\u00B0C), but vegetative cover at measured s i t e s was often lower than in the present study (Bamberg and Major 1968, Ballard 1972, Douglas and B l i s s 1977). S o i l temperatures were measured at 50 cm below the surface by van Ryswyk (1969) in Alpine Brown, discontinuous ash s o i l s of the study area during 1965 and 1966. Temperatures ranged from 6-8\u00C2\u00B0C over the growing season, with a recorded maximum of 10\u00C2\u00B0C (August) and minimum of 1\u00C2\u00B0C (October). These temperatures are very similar to those obtained at a depth of 20 cm in the present study. Winter depth of frost penetration was 1 78 estimated to reach 180 cm in these s o i l s , and has an inverse r e l a t i o n to the degree of snow accumulation (van Ryswyk 1969). CONCLUSIONS Microscale patterns in the vegetation were detected. Preliminary studies suggest that the d i s t r i b u t i o n of communities within the study area are possibly related to some of the measured abio t i c factors. It is possible that b i o t i c factors, such as the r e l a t i v e competitive a b i l i t i e s of dominant species, and the resultant vegetative spread of each, may play a role. The d i s t r i b u t i o n a l patterns are unrelated to aspect. The phenology of some alpine species appears to be influenced by the dominant species they occur with, or by the aspect at which they grow. Phenological differences between species had l i t t l e r e l a t i o n s h i p to i n t e r s p e c i f i c associations. The large number of i n t e r s p e c i f i c associations detected belie previous views held by alpine ecologists on the lack of patterning at this scale. Patterns within communities were assumed non-existent, and species d i s t r i b u t i o n s e s s e n t i a l l y random, while large-scale community patterns were related to a b i o t i c factors. Although conclusive explanations for the existence of these associations are not possible with sampling data alone, trends within these data indicate that temporal partioning and symbiotic nitrogen f i x a t i o n in legume and lichen species have l i t t l e influence. Species morphology, p a r t i c u l a r l y with respect to roots, and microenvironmental effects (e.g., seedlings in cushion plants) appear to be more important 1 79 factors. As a wide variety of possible processes or mechanisms may contribute to the formation of species associations, extensive testing of the hypotheses and interpretations presented in thi s thesis is required before cause and effect relationships can be established. I n t e r s p e c i f i c associations varied considerably over the study area, with many associations detected only once. Associations of particular plant species often changed at each sampled s i t e . This suggests that population d i f f e r e n t i a t i o n of alpine species occurs over very short distances. The formation of associations may depend more on certain c h a r a c t e r i s t i c s of the genotypes i n i t i a l l y present, and less on the taxonomic or sp e c i f i c identity of that genotype. As well, less strongly competitive subordinate species form more positive associations than do dominant plants. A high degree of competitive a b i l i t y is suspected for dominant species that have frequent positive associations with lichen species and few positive (and many negative) associations with vascular species. The p l o t l e s s p o i n t - l i n e , or species juxtapositions, method used to detect i n t e r s p e c i f i c association was found to be useful for low-growing alpine vegetation, interspersed with bare patches or rock. The distance between points is f l e x i b l e , and the recording of species sequences is objective. The necessity of a p l o t l e s s technique was apparent after a comparison of resulting small scale associations, with 'those detected using quadrat data. One problem with this and other existing p l o t l e s s methods, is that results are limited to i n t e r s p e c i f i c 1 8 0 associations only. This is primarily due to the extreme d i f f i c u l t y in determining individual plants in closed vegetation patches. As i n t r a s p e c i f i c association may provide important preliminary data on the intensity of competition between members of the same species, further research is needed to provide an adequate sampling method for th i s type of association. 181 VI. SUMMARY VEGETATION 1. Selected alpine plant communities of Lakeview Mountain, Cathedral Provincial Park were examined, as well as the corresponding ab i o t i c factors of s o i l s and microclimate. Multivariate analysis of percentage cover data for 6, 2 m X 30 m transects revealed three major community types, dominated by Kobresia myosuroides, Carex scirpoidea (with one t r a n s i t i o n a l area dominated by both Kobresia myosuroides and Carex scirpoidea), or by Carex scirpoidea and Carex capitata (with Salix n i v a l i s as an additional dominant at one s i t e ) . The d i s t r i b u t i o n and composition of these communities had l i t t l e r e l ationship with aspect or with the s o i l s and microclimatic parameters measured. Subsurface s o i l temperatures, however, were generally 3-4\u00C2\u00B0 C cooler in Kobresia myosuroides communities, than at other s i t e s . 2. Phenological stages for vascular species were recorded during the summer of 1980, within each sampled transect. A number of species have delayed phenology in Kobresia myosuroides communities, compared to other sampled communities. A similar delay was observed for some species within Carex scirpoidea/Carex capitata dominated s i t e s , when compared to areas dominated solely by Carex scirpoidea. In addition, a number of species tend to flower e a r l i e r in south facing s i t e s , although other species show l i t t l e phenological variation with aspect. 182 3. Small scale patterns in the form of s i g n i f i c a n t associations between species-pairs were detected in a l l communities. A p l o t l e s s p o i n t - l i n e sampling technique was used to determine species juxtapositions ( i . e . , the t r a n s i t i o n s between d i f f e r e n t species). Subsequent analysis compared observed species sequences to expected values generated using a Markov chain model for random d i s t r i b u t i o n . A normally-d i s t r i b u t e d standardized residual s t a t i s t i c was used to determine s i g n i f i c a n t (p^0.05) positive and negative i n t e r s p e c i f i c associations. This method is most useful for low-growing vegetation interspersed with bare patches or rock. Similar p l o t l e s s techniques, such as the contact sampling method, depend on continuous ground cover. The necessity of p l o t l e s s techniques to determine small scale associations was apparent after associations at the scale of a 20 X 50 cm quadrat were found to be very d i f f e r e n t from those detected at 2 cm inte r v a l s with p o i n t - l i n e s . 4. Patterns were abundant at t h i s small scale, with a t o t a l of 182 s i g n i f i c a n t positive associations and 103 s i g n i f i c a n t negative associations recorded between d i f f e r e n t species-pairs. Of the species sampled, 88% had at least one association in one vegetation group (sampled stand). Although i t i s not possible to make conclusive statements about the processes generating these patterns from associations alone, certain associations suggest potential c a u s a l i t i e s . Possible mechanisms generating positive associations have been discussed. B r i e f l y , these are: i) Niche d i f f e r e n t i a t i o n - p a r t i c u l a r l y temporal p a r t i t i o n i n g , 183 d i f f e r e n t i a l morphology, and p h y s i o l o g i c a l v a r i a t i o n . i i ) B a l a n c i n g of c o m p e t i t i v e a b i l i t i e s , w i t h subsequent p r e v e n t i o n of c o m p e t i t i v e e x c l u s i o n . i i i ) P r e d a t i o n , l e a d i n g to the s u p p r e s s i o n of s u p e r i o r c o m p e t i t o r s , a l l o w i n g c o - o c c u r r e n c e w i t h weaker ones . i v ) L o c a l i n c r e a s e s in a v a i l a b l e n u t r i e n t s by c e r t a i n s p e c i e s through n i t r o g e n - f i x i n g symbionts and m y c o r r h i z a l root i n f e c t i o n s , and v) M o d i f i c a t i o n of m i c r o s i t e c o n d i t i o n s by c e r t a i n s p e c i e s , which proves b e n e f i c i a l f o r o ther s p e c i e s . P o s s i b l e mechanisms g e n e r a t i n g n e g a t i v e a s s o c i a t i o n were a l s o d i s c u s s e d : i ) S i m i l a r morphology - p a r t i c u l a r l y w i t h r e s p e c t to r o o t s (n iche o v e r l a p ) . i i ) D i f f e r e n c e s i n r e s o u r c e requirements and e n v i r o n m e n t a l t o l e r a n c e s between s p e c i e s . i i i ) C o m p e t i t i v e e x c l u s i o n of weaker c o m p e t i t i o r s by s t r o n g e r ones . As p o s i t i v e and n e g a t i v e s p e c i e s a s s o c i a t i o n s vary c o n s i d e r a b l y between sampled s i t e s in the study a r e a , and few major e n v i r o n m e n t a l d i f f e r e n c e s e x i s t between s i t e s , the genotype or i n d i v i d u a l and not the taxonomic s p e c i e s may be the important e c o l o g i c a l u n i t i n the a l p i n e zone . 5. I n s i g h t i n t o the r e l a t i v e c o m p e t i t i v e a b i l i t i e s of the three major dominant s p e c i e s may be o b t a i n e d by examining the i n t e r s p e c i f i c a s s o c i a t i o n s of each under v a r y i n g c o n d i t i o n s , as w e l l as p h e n o l o g i c a l data for s u b o r d i n a t e s p e c i e s . Data suggest 184 a competitive hierarchy of dominant species within the study area, with Kobresia myosuroides as the most competitive, compared to a l l other species, followed by Carex capitata, and, f i n a l l y , by Carex sc irpoidea. The r e l a t i v e competitive a b i l i t i e s of these three major dominants may be a c r i t i c a l factor a f f e c t i n g the d i s t r i b u t i o n of communities at the study s i t e . Less strongly competitive subordinate species appear to have a greater a b i l i t y to form associations than do the dominant plants. SOILS So i l s within the study area are c l a s s i f i e d as Alpine Dystric Brunisols, following the Canadian System, and are coarse textured, strongly a c i d i c , and high in organic matter. Low nutrient levels p a r a l l e l other alpine studies, and are r e l a t i v e l y constant between sampled s i t e s . CLIMATE Mesoclimate was r e l a t i v e l y uniform over the study area during the 1980 growing season, as were microclimatic a i r and s o i l temperature p r o f i l e s and a i r humidity p r o f i l e s . Maximum subsurface temperatures were lower than that previously reported for alpine areas in western North America, with the lowest temperatures occurring beneath Kobresia myosuroides dominated vegetation. 185 VII. LITERATURE CITED Aarssen, L.W. 1983. Interactions and coexistence of species in pasture community evolution. Ph.D. thesis. Univ. of B r i t i s h Columbia, Vancouver, B.C. 249 p. Aarssen, L.W., R. Turkington, and P.B. Cavers. 1979. 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Marine sedimentation and extensive vulcanism characterized t h i s period. The sea drained near the end of the T r i a s s i c and the sediments and lava were compressed and folded during a period of deformation in the Jurassic (Rice 1960). These metamorphosed rocks were then intruded by magma, which c r y s t a l l i z e d to form g r a n i t i c plutons, such as Lakeview granodiorite and and Cathedral quartz monzonite (Daly 1912). Early in the Cretaceous period, erosion exposed e a r l i e r intrusive rock (Rice 1960) and the Cathedral Park area was included within a new, narrow marine basin (Rudkin 1964). Sedimentation and vulcanism characterized this time, with subsequent termination by Late Cretaceous orogeny (folding and f a u l t i n g ) , followed by erosion and peneplain formation (McTaggart 1970). No rock of the Cretaceous age i s presently exposed in Cathedral Park (Melcon 1975). Lavas and l o c a l lake sediments were deposited on the leveled land during the Tertiary and are represented in Cathedral Park as Mid-Eocene Princeton basalt and sedimentary rock (Rice 1960). Vulcanism and sedimentation were followed by folding and erosion, and the granites, d i o r i t e s , and granodiorites of the eastern North Cascades were produced during this time (Misch 1966). Further u p l i f t occurred in the late Pliocene and Pleistocene epochs with subsequent erosion and weathering forming deep, dissected valleys with residual h i l l s and mountains of more resistant rock, termed monadnocks, r i s i n g above the elevated Teriary peneplain (R ice 1960, Holland 1964). Lakeview Mountain is an example of such a monadnock. During the Pleistocene epoch, the Cordilleran ice sheet covered most of B r i t i s h Columbia, with the f i n a l advance, the Fraser Glaciation (late Wisconsinan), l a s t i n g approximately 15,000 years (Crandell 1965). The Fraser g l a c i a t i o n produced the bulk of g l a c i a l features seen in B r i t i s h Columbia (Tipper 1971). Tipper (1971) c i t e s evidence for a pre-Fraser, Fraser, and very limited post-Fraser g l a c i a t i o n in the central i n t e r i o r of B.C. The chronology of a subsequent Hypsithermal Interval and Neoglaciation has been outlined by Porter and Denton (1967). Ice sheet development began in mountainous ter r a i n with the advance of alpine g l a c i e r s . Mountain ice sheets gathered around the Coast and Cariboo-Columbia Mountains and subsequently merged. A south-eastern segment of ice formed after this coalescence, which flowed across the Washington-British Columbia border after additions from the Monashee Mountains, south Coast Mountains, and other l o c a l centers (Nasmith 1962, Tipper 1971). There i s evidence that the continental ice covered mountains as high as 2590-2620 m in the study area, although elevations above 2286 m were not reached in Wisconsin time (Prest 1957, Rice 1960). Holland (1964) and Nasmith (1962) both state, however, that the ice did not a t t a i n elevations over 2134 m at i t s 214 maximum in southern B r i t i s h Columbia. Evidence for a 2286-2377 m upper l i m i t of e f f e c t i v e g l a c i a l erosion has been given by Melcon (1975) for Cathedral Provincial Park where tor landforms (rock exposed in s i t u by chemical and physical weathering) occur exclusively above th i s upper l i m i t . Intense alpine g l a c i a t i o n occurred above the upper l i m i t of the Cordilleran ice sheet and produced cirque basins on north and north-east aspects and serrate peaks and ridges; in contrast to the smooth and rounded topography of areas below the ice sheet (Holland 1964). The ef f e c t s of alpine g l a c i a t i o n above 2440 m i s marked in Cathedral Park. Vulcanism was extensive during the late Pliocene and early Pleistocene and volcanic cones such as Mt. Baker and Glacier Peak were superimposed on exi s t i n g Cascade Mountain peaks during this time (Coombs 1939). S u r f i c a l ash deposits reported within and to the south of the study area (Bockheim 1972, van Ryswyk 1969) resulted from a number of recent volcanic eruptions. Major sources of ash are l i k e l y to be Glacier Peak, Mt. Mazama, and Mt. St. Helens in the Cascade Mountains. The oldest ash source i s Glacier Peak, erupting 12,000 years ago and d i s t r i b u t i n g ash to southern B r i t i s h Columbia, Alberta, and Montana (Powers and Wilcox 1964, F r y x e l l 1965, Wilcox 1965). Extensive ash deposits resulted from the Mt. Mazama eruption at Crater Lake in southern Oregon approximately 6600 years B.P., occurring as far north as southern B r i t i s h Columbia (Powers and Wilcox 1964, Wilcox 1965, Westgate et a l . 1969). Mt. St. Helens produced three ash deposits, dated at 160 year B.P. (Mullineaux 1964), 500 years B.P., and 3000 years B.P. (Crandell et a l . 1969), although known ash d i s t r i b u t i o n s suggest only the 3000 year B.P. ash reached as far north as Cathedral Park (Okazaki et a l . 1972, Nasmith et a l . 1967). L i t t l e or no ash from the most recent Mt. St. Helens eruption (1980) i s evident in the study area. It i s not l i k e l y Mt. Rainier ash (2300 and 2000 years B.P.) (Crandell et a l . 1969, Wilcox 1965), or Bridge River ash (2400 years B.P.T\" (Nasmith et a l . 1967) reached Cathedral Park. 215 APPENDIX B - SOILS S o i l s of the Princeton map area, which includes the Cathedral Park study area, have been c l a s s i f i e d by Green and Lord (1979). S o i l s at the forest-alpine t r a n s i t i o n within t h i s map area were determined by these workers to be members of the Alpine Subgroups of the Dystric Great Group of the Brunisolic Order ( S o i l Survey Committee of Canada, 1968). S o i l s within the alpine zone of Lakeview Mountain have been examined in d e t a i l by van Ryswyk (1969) and van Ryswyk and Okazaki (1979). Three d i f f e r e n t s o i l types were characterized by van Ryswyk (1969), the most extensive (over 50% of the area studied) being Alpine Brown with discontinuous ash layers, van Ryswyk (1969) stated that t h i s s o i l type was comparable to the Alpine Dystric Brunisol of the Canadian System, although a l a t e r report (van Ryswyk and Okazaki 1979) referred to this s o i l as an Orthic Sombric Brunisol. Alpine Brown, Discontinuous Ash s o i l s are included within the Incepticol Order of the U.S. S o i l C l a s s i f i c a t i o n System. Douglas and B l i s s (1977), working near the study area in the North Cascade alpine of Washington, reported Inceptisols beneath a wide variety of alpine plant communities from snowbed s i t e s to well-drained dry graminoid and sedge vegetation. Alpine Brown, Discontinuous Ash s o i l s are also comparable to the Alpine Turf Great S o i l Group described by Retzer (1956, 1962), Johnson and B i l l i n g s (1962), and Nimlos and McConnell (1962) for the Rocky Mountains of Colorado, Wyoming, and Montana, and by Bockheim (1972) for Mt. Baker in the North Cascades. Alpine Brown, Discontinuous Ash s o i l s develop on moderately acid parent material of medium to coarse texture. They are characterized by thin organic surface layers (L-H) and moderately thick turfy Ah over Bm horizons (van Ryswyk 1969). Alpine Brown, Continuous Ash p r o f i l e s were also characterized on Lakeview Mountain (van Ryswyk 1969). These s o i l s have a B horizon similar to the Bf horizon found in Podzol s o i l s . Sombric Humo-Ferric Podzols have been c l a s s i f i e d in t h i s alpine zone on the basis of sesquioxides and organic matter accumulation in the i l l u v i a l B horizon (van Ryswyk and Okazaki 1979), Alpine Podzols (Spodosols) have also been reported under alpine krummholz and heath vegetation in the North Cascades (Douglas and B l i s s 1977) with further reports from several alpine areas in B r i t i s h Columbia (Sneddon 1969, Sneddon et a l . 1972, Alberta (Baptie 1968, Broad 1973), and Maine (Bliss and Woodwell 1965). Structure s o i l s such as sorted stone patterns and stone r i v e r s have also been described on Lakeview Mountain (van Ryswyk 1969) and are correlated with the reduction of snow cover found on exposed ridges. Extensive lichen cover suggests recent s t a b i l i t y . In addition, broken rock units occur on promentories, rock headwall and talus units occupy cirque basins, and snowbank units characterize lee positions. 216 Buried horizons are common in Lakeview alpine s o i l s , indicating severe disturbance by cryoturbation as well as slope wash and wind erosion. Charcoal fragments, larger than would be possible from existing woody vegetation, have been found in surface and buried horizons at a l t i t u d e s up to 2440 m (van Ryswyk 1969). The past existence of a more extensive forest of coniferous trees and ericaceous shrubs has been argued by van Ryswyk and Okazaki (1979). A charcoal fragment found 70 cm below the s o i l surface at an elevation of 2485 m on Lakeview Mountain has been dated at 9120 years B.P. (van Ryswyk 1971), Ash buried with the charcoal has been i d e n t i f i e d as Mt. Mazama and Mt. St. Helens ash, deposited between 3000 - 3500 years B.P., indicating burial occurred after 3000 years B.P. A period of intense s o l u f l u c t i o n at the close of a minor g l a c i a l i n t e r v a l 1200 - 1000 years B.P. has been reported by Benedict (1966) and is possibly when horizon b u r i a l occurred. S o i l parent materials are considered residual and consist primarily of coarse, p a r t i a l l y weathered quartz monzonite cr y s t a l s (Melcon 1975) and other medium-grained d i o r i t e type rocks with fine-grained volcanic materials (van Ryswyk 1969). Fine s i l t or clay i s absent from the parent material, and the small amounts that occur in these s o i l s are formed in s i t u or deposited by percolating ground water (Melcon 1975). Much of the drainage in these s o i l s occurs as seepage over nearly impermeable C horizons. A l l s o i l s have been influenced by volcanic ash, burying and mixing of horizons, frost heaving, s o l u f l u c t i o n , surface erosion, and c o l l u v i a l a c t i v i t y (van Ryswyk 1969). Slow rates of chemical weathering due to cold temperatures and the erosive action of physical processes contribute to the general immaturity of s o i l p r o f i l e s found in alpine areas (Retzer 1974). 217 APPENDIX C ~ PERCENTAGE COVER DATA FOR SIX TRANSECTS Percentage cover data for composite samples from transects A-F are presented in th i s appendix. Rare species have less than 5 occurrences in each transect data set or cover values of less than 5% in a l l transect samples. Trace (T) denotes less than 5% cover. 218 TRANSECT A COMPOSITE SAMPLES VASCULAR SPECIES 1 2 3 It 5 6 7 8 9 10 11 12 13 15 16 ARENARIA OBTUSILOBA 15 8 8 8 T T 8 T 13 12 T T T T CAREX CAPITATA 3 25 *5 23 38 27 <0 17 20 28 25 15 37 33 28 CAREX NAROINA T T T 5 CAREX SCIRPOIDEA 12 17 20 23 28 28 itO 15 17 22 28 17 33 32 33 CERASTIUM BEERINGIANUM T T T T T ERIGERON AUREUS T T T T T T 7 T T T T T T T FESTUCA OVINA 10 13 10 17 10 8 7 10 8 10 7 13 12 10 10 10 LUPINUS LYALLI1 T T T T T T 5 T T T T LUZULA CAMPESTRIS T T 7 7 5 6 T T T T 7 8 7 T 5 8 OXYTROPIS MONTICOLA 8 T T T T T T T T PENSTEMON PROCERUS 5 T 5 POLEMONIUM PULCHERR1 MUM T POTENTILLA DIVERSIFOLIA 18 13 22 23 17 11 18 20 9 T 9 20 13 6 12 9 SELAGINELLA DENSA 12 10 T 10 8 T T T 8 5 13 8 12 9 7 7 SILENE ACAULIS T T T T T 6 T T SOLI DAGO MULTIRAD 1 ATA T T STELLARIA LONGIPES T T T 7 T T T T T T T TRISETUM SPICATUM T T T T T T T T T T T T 23 T 15 12 12 T 27 "Thesis/Dissertation"@en . "10.14288/1.0095812"@en . "eng"@en . "Botany"@en . "Vancouver : University of British Columbia Library"@en . "University of British Columbia"@en . "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en . "Graduate"@en . "Interspecific associations, phenology, and environment of some alpine plant communities on Lakeview Mountain, Southern British Columbia"@en . "Text"@en . "http://hdl.handle.net/2429/23995"@en .