Mires of Vancouver Island, British Columbia: Vegetation classification and differences between disturbed and undisturbed mires

My research focuses on three key aspects of mire ecology: (1) delineation of mire regions using floristic criteria; (2) classification of mire plant communities on Vancouver Island, British Columbia; and (3) determining whether floristic, hydrological, and chemical differences exist between disturbed and undisturbed mires. Mires are generally uncommon in southwestern B.C., and have high conservation significance owing to their rarity and uniqueness. Many mires have been affected by human disturbance, particularly drainage.; I identified four floristically and geographically distinct groups of mires based on ordination and classification of floristic data. I also confirmed that mires occurring at low elevations on northern and western Vancouver Island are floristically similar to those in the Prince Rupert area of northwestern B.C., and that mires found at low elevations on eastern Vancouver Island are similar to those on the adjacent Mainland.; At the community scale, I identified 20 plant associations. I grouped the associations into six orders. The Ledum groenlandicum-Kalmia microphylla ssp. occidentalis order consists of 10 associations characterizing hummock, lawn, and heath communities found in bogs and poor fens. The Triantha glutinosa order includes six associations typifying lawn communities in moderate-rich and rich fens. The remaining four orders (i.e., the Eriophorum angustifolium order, the Juncus supiniformis order, the Rhynchospora alba-Scheuchzeria palustris order, and the Nuphar lutea ssp. polysepala order) each consist of single associations characterizing communities occurring in wet microhabitats.; I used statistical analyses to confirm the existence of significant differences in seasonal water table fluctuations and chemical composition of soil water between disturbed and undisturbed mires on eastern Vancouver Island. Seasonal water table fluctuations are typically greater in disturbed mires, as are specific conductivity values and most major cation concentrations. Conversely, pH values in disturbed mires are relatively low.; Vegetation structure and community composition also differs between disturbed and undisturbed mires. Central areas of disturbed mires are characterized by dense, species-poor tree and shrub communities, and an absence of communities associated with wet microhabitats. While plant species richness at the site scale is relatively low in disturbed mires, at the plot scale it is not significantly lower than in undisturbed mires.