Fish Species Traits and Communities in Relation to a Habitat Template for Arctic Rivers and Streams
Nicholas E. Jones, Garry J. Scrimgeour, and William M. Tonn
Abstract.—We develop a conceptual model of habitat factors, operating as filters at multiple spatial and temporal scales that structure local fish assemblages in flowing waters of Arctic North America. Following the habitat template approach, we classify streams into six types based on environmental gradients, including ice formation, flow and temperature regimes, sediment dynamics, and edaphic factors. We discuss likely mechanisms influencing Arctic stream fish assemblages among the six stream types and consider this habitat template in the context of regional and local filters. There is a general increase in species richness from the eastern Arctic to Alaska that is inversely proportional to the distance from the Beringian glacial refugium. The fish fauna of Arctic streams comprises nine different families, although 14 of 24 species (58%) are members of Salmonidae. Certain life history traits are predicted to be advantageous in a periglacial environment known for cold, impoverished environments with highly variable yet generally predictable ice conditions. Examples of adaptive traits displayed by Arctic fishes include fall spawning, relatively large egg size, longevity, habitat and diet generalists, and efficient metabolism. Life history theory predicts that periodic strategists should dominate in the Arctic environment. Nevertheless, in the face of a rapidly changing climate and increasing resource development, there is much need for additional research on relationships between the traits of Arctic stream fishes and their habitat.