Fish assemblages on two continents

Aim: Fish assemblages –whether defined by taxonomy or functional traits—respond to regional and local habitat variation. We sampled rivers of Mongolia and the western United States (US) to determine the scale at which habitat could predict fish assemblage variation, classified by taxonomy or functional traits. Our hypothesis was that fish assemblages could be predicted using valley-scale hydrogeomorphology and reach-scale hydrology. We further predicted that if valley-scale variables explained high variation in fish assemblages then reach-scale variables would explain additional dimensions.
Location: Mongolia, United States
Methods: We evaluated reach- and valley-scale hydrogeomorphology of rivers in the US and Mongolia in each of three ecoregions, grassland, forest, and endorheic. Fishes were collected using backpack electrofisher following standard protocols.
Results: Ordinations resulted in distinct assemblage patterns that corresponded with habitat variables at both valley- and reac...