Classification of High-elevation, Non-forested Plant Communities in Coastal British Columbia Summary Non-forested ecosystems dominate high elevation sites in coastal British Columbia, yet there has never been a comprehensive classification or mapping of all high- elevation community types. The objective of this study is to collate and expand upon previous classifications, and thereby to increase our understanding of the habitats and composition of these plant communities. Non-forested plant communities occur where trees are permanently absent, or where they can survive only as prostrate or stunted shrubs. Within our region, non- forested communities generally dominate sites that are snow-free for <4 months. We aimed to develop a classification that organizes communities into groups in a way which shows the greatest number of relationships, is easily retained in memory, and is easily conveyed through instructions. Combining previous studies and new sampling allowed us to prepare the most comprehensive classification of high-elevation, non-forested plant communities in coastal BC to date. We present the classification of plant communities into vegetation units that include (in increasing rank): subassociations, associations, alliances, and orders. Diagnostic tables show floristic affinities among the vegetation units and interpret their relationships to environmental gradients. We describe the environment associated with the vegetation units, then discuss their relationships. Relating predictable patterns of plant communities to environmental gradients also allowed us to suggest eight habitat types that may aid in the future mapping of high-elevation ecosystems (Figure 1). Study Sites and Methods The study is concentrated in southern coastal British Columbia (including Vancouver Island, the coastal lowlands, Coast Mountains, and windward slopes of the Scientia Silvica Extension Series, Number 29, 2001 Cascade Mountains), but it also extends northward towards Prince Rupert. Its main elevational range is from the upper subalpine (parkland MH subzones) to the alpine (AT zone). Our combined dataset of published and unpublished studies included 282 plots (relevés). All were sampled in areas that had no history of human influence. Vegetation data for all datasets were collected using standard methods. Each plot was placed in a portion of a community that was relatively uniform in floristic composition, structure, and site attributes (slope position, aspect, gradient, and ground cover). Plot size increased with increasing floristic diversity and structural complexity of vegetation, varying from 0.5 to 100 m². All plant species present within the plot were identified and their cover was estimated. Environmental data were collected for each data set, including slope position, aspect, and gradient. A soil pit was dug at each plot to describe and identify soils. We estimated SMR and SNR for all plots. Results and Discussion Predictable relationships can be used to infer certain environmental conditions from the presence of a given plant community or, conversely, to forecast the presence or development of plant communities given certain environmental conditions. The relationship between these factors in non-forested high-elevation communities may be stronger than in forested communities, since the gradients tend to be steeper. The steepest gradients develop in relation to time of snowmelt, distance from standing or flowing water, and time elapsed since deglaciation or disturbance. Other environmental factors that affect plant communities (and can be used to predict their presence) include: aspect, slope gradient, slope position, parent material, soil texture, and drainage patterns. Scientia Silvica is published by the Forest Sciences Department, The University of British Columbia, ISSN 1209-952X Editor: Karel Klinka (klinka@interchange.ubc.ca) Production and design: Christine Chourmouzis (chourmou@interchange.ubc.ca) Financial support: Research Branch and the Vancouver Forest Region (BC Ministry of Forests) For more information contact: Karel Klinka Copies available from: www.forestry.ubc.ca/klinka, or K.Klinka, Forest Sciences Department, UBC, 3036-2424 Main Mall, Vancouver, BC, V6T 1Z4 Ordering Information This report is available in full colour or black-and-white printed versions or in electronic format on the Scientia Silvica CD-ROM. Ordering information is available on www.forestry.ubc.ca/klinka or from Karel Klinka (klinka@interchange.ubc.ca) References Brett, R.B., K. Klinka, and H. Qian. 1998. Classification of high-elevation, non-forested plant communities in Coastal British Columbia. Forest Sciences Department, University of British Columbia, Vancouver, BC. G2: shrub-dominated G1: herb-dominated Figure 1. Generalized vegetation-environment relationships. A Krummholz Habitat code Characteristic Community B Sheet-wash C Heath D Snow basin E Wetland F Fragmented rock G Lush herbaceous H Lithic Habitat description Distribution Dominant life-forms Plant orders represented exposed cliffs and ridges with early snowmelt unstable soils (sheet-wash and solifluction) with late mesic, well-drained sites on all aspects late-snowmelt (chionophilous) patches and basins near moving water (fens) or stagnant water (bogs) chomophytic sites: talus slopes, rubble fields, and moraines moist to wet slopes, stream edges, seeps, and avalanche tracks exposed rock (rupicolous) sites with early snowmelt (1) Rhizocarpon geographicum; (2) Phlox diffusa (3) Marsupella brevissima; (5) Cassiope- Phyllodoce (5) Cassiope- Phyllodoce; (10) Eriophorum angustifolilum (3) Marsupella brevissima; (4) Carex nigricans (4) Carex nigricans; (10) Eriophorum angustifolium; (11) Carex pluriflora (5) Cassiope- Phyllodoce; (6) Carex spectabilis; (9) Alnus viridis (1) Rhizocarpon geographicum; (2) Phlox diffusa (7) Philonotis fontana; (8) Valeriana sitchensis; (9) Alnus viridis dwarf trees and evergreen shrubs herbs, graminoids, and liverworts evergreen shrubs liverworts and shrubs mosses and graminoids herbs and graminoids herbs, mosses, and deciduous shrubs mosses, evergreen shrubs, and herbs alpine alpine upper upper subalpine/alpine upper upper upper soil rubble soil and rubble rock Schematic slope profile for typical habitat types Legend