Distributions of freshwater fishes in ecoregions and hydroregions of Alaska

Abstract

AbstractWe examined the spatial distributions of Alaskan freshwater fishes using 2 frameworks, ecoregions and hydroregions (catchments). Ecoregions are defined by climate, terrain, vegetation, and soils; their utility in explaining distributions of aquatic organisms is based upon terrestrial–aquatic linkages. Analysis of the probable dispersal of aquatic organisms along past and current hydroregions provides an alternative and likely complementary path to understanding distributions of aquatic organisms. We use published distribution records for freshwater fishes of Alaska to construct a matrix of presence/absence records for each fish species in ecoregions and hydroregions of Alaska. We assessed faunal similarities among ecoregions and hydroregions using the Jaccard index. Classification analyses (two-way indicator species analysis [TWINSPAN] and unweighted pair-group method using arithmetic averages [UPGMA] cluster analysis) were used to group ecoregions and hydroregions. Similarities of fish faunas wer...