Geographical and Ecological Relationships of the Arctic-Alpine Vascular Flora and Vegetation, Arrigetch Peaks Region, Central Brooks Range, Alaska

Abstract

The arctic-alpine vascular flora of the Arrigetch Peaks region of the central Brooks Range, Alaska, is composed of a high percentage of arctic-montane circumpolar taxa. The flora shares the highest percentage of taxa with regions in central Alaska and Yukon Territory. Floristic similarity decreases both to the north and south within Alaska. The study area shares approximately 21-34% of its flora with most arctic locations and with alpine locations in mountain ranges as far south as the Colorado Rocky Mountains in North America and the Altai in Asia. The family Asteraceae has the largest number of taxa in the Arrigetch flora, similar to alpine floras in the Rocky Mountains. However, representative arctic floras surveyed had a higher percentage of taxa in Cyperaceae and Poaceae. An analysis of the geographical affinities of dominant and characteristic taxa in the forty-three plant associations dominated by vascular taxa in the study area was performed. It indicated that well-drained and poorly-drained late lying snowbeds, subnival ridges, screes, south-facing bluffs, meadows, and calcareous and non-calcareous ridges are dominated and/or characterized by Beringian or Alaska-Yukon endemic taxa. These taxa surely occurred in the Alaska portion of the unglaciated Pleistocene refugium known as 'Beringia', and most likely occupied habitats