Arctic Vegetation Archive - Alaska: Unalaska Vegetation Plots.
In 2007, one of the first quantitative studies of vegetation from sea level to alpine on Unalaska Island in the Aleutian Islands was completed (Talbot et al. 2010). The focus of the study was to 1) describe the major plant communities along environmental gradients, 2) identify the main vegetation types and communities and determine their relationship to select site factors, and 3) compare these communities to other studies completed in southern Alaska. A combined Braun-Blanquet and multivariate analysis approach was applied to the data for the 70 plots and showed a complex gradient primarily influenced by soil moisture, elevation and pH. Funding for this project came from the U.S. Fish and Wildlife Service.
Cover-abundance was estimated for all vascular plants, bryophyte, and macrolichens using the nine-point original scale of Westhoff and van der Maarel (1973) in sixty-nine subjectively chosen plots on Unalaska Island and one plot on Amaknak Island. Eleven plant communities in six broad ecological groups were identified in this study. These plant communities occur in 6 broad habitat types including: 1) Dry coastal beach and sand dune vegetation (9 plots), 2) Willow, grass, fern, forb thickets (4 plots), 3) Wet acidic sedge, forb mire (9 plots), 4) Late snowbed communities (3 plots), 5) Moist and dry acidic dwarf-shrub and lichen heaths (Vaccinium uliginosum, Empetrum nigrum, Ledum decumbens, Spiraea beauverdiana, and Betula nana-lichen heaths (22 plots), and 6) Alder communities (23 plots).
Plots were 25 square meters (5 by 5 m) in area and environmental data collected include elevation, litter cover, slope inclination, ecological moisture regime, and mesotopography. Plots were not permanently marked but GPS locations in degrees, minutes, seconds were recorded. A single soil sample was collected from each plot and brought back to the lab for chemical assessment.
A summary of these data is presented in the publication listed below.
References
Talbot, S. S., W. B. Schofield, S. L. Talbot, and F. J. A. Daniels. 2010. Vegetation of eastern Unalaska Island, Aleutian Islands, Alaska. Botany 88:366-388.
