Vegetation at Jarmin Pass, Attu Island, Alaska. Stephen Talbot

The Biology Department at the University of Massachusetts Amherst is hosting a seminar "Mountain Vegetation of Eastern Attu Island, Alaska" at noon on October 19, 2005; it will be given by Stephen Talbot, Division of Natural Resources for the US Fish and Wildlife Service, and Sandra Talbot, US Geological Survey (USGS.) From their field investigations, the mountain vegetation of eastern Attu Island was described and analyzed to identify the major vegetation types and their relationship to 13 site factors.  The vegetation of the Aleutian Islands remains little documented and this relevé study provides a basis for future comparison with other areas.  The Talbots present the first analysis of Attu Island mountain vegetation; this work complements our earlier study of the coastal vegetation of Attu Island.  Sixty-five relevés represent the range of structural and compositional variation in the matrix of mountain vegetation and landforms.  Data are analyzed by multivariate methods using the MULVA-5 computer package and ordered with Wildi’s numerical procedure to produce results similar to phytosociological tabular classification.  Refinement of the classification is enhanced using the JUICE software package.  Classification distinguished ten major vegetation types:  meadows (Athyrium filix-femina-Calamagrostis Canadensis); tall forb (Carex macrochaeta-Anenome narcissiflora, Castilleja unalaschensis-Picris hieracioides);  alluvial meadow (Calamagrostis Canadensis); wet meadow (Carex lyngbyaei); marsh (Hippuris montana-Racomitrium sudeticum); snowbed (Luzula arcuata-Oligotrichum hercynicum) fellfield; mires (Carex pluriflora-Sphagnum squarrosum, Trichophorum caespitosum-Iris setosa); and heath (Vaccinium uliginosum-Empetrum nigrum).  In an NMS ordination using PC-ORD, these vegetation types are interpreted in response to a complex topographic gradient.  Primary environmental factors controlling floristic composition include elevation, pH, aspect, ecological moisture class, and soil organic matter content.  In the analysis, the researchers phytogeographically compared the vegetation of Attu Island with that of the Commander Islands, Russia.