Identifying Suitable Habitat for Chinook Salmon across a Large, Glaciated Watershed

Abstract

AbstractEcosystem management requires information on habitat suitability across broad scales; however, comprehensive environmental surveys in remote areas are often impractical and expensive to carry out. Intrinsic Potential (IP) models provide a means to identify on a broad scale those portions of the landscape that can provide essential habitat for various freshwater fish species. These models are derived from watershed patterns and processes that are persistent and not readily affected by human activities. We developed an IP model for rearing habitat of Chinook Salmon throughout the Copper River watershed (63,000km2) in southcentral Alaska, utilizing digital elevation models, expert opinion, and field surveys. Our model uses three variables—mean annual flow, gradient, and glacial influence—and adequately predicts where probable habitat for juvenile Chinook Salmon occurs across this large landscape. This model can help resource managers map critical habitat for salmon throughout the Copper River watershed, direct field research to appropriate stream reaches, and assist managers in prioritizing restoration actions, such as culvert replacement. Intrinsic Potential modeling is broadly applicable to other salmonid species and geographies and may inform future work on the ecological impacts of climate change in polar and subpolar river systems.