Impact of Land Use Change on High-Quality Salmon Habitat in Central Puget Sound

Development has impacted many streams and rivers draining to the Salish Sea. Development typically has detrimental impacts on salmon populations and habitat impacts will increase with the expected increase in human population predicted for the next century. Salmon production in freshwater varies spatially and often a few areas can be responsible for supporting a large proportion of a population. If development is disproportionately focused at locations capable of supporting high levels of production, the detrimental impact of future development could make it difficult to maintain naturally spawning populations of salmon. We utilized a model to predict habitat suitability for coho salmon for stream reaches in four counties in central Puget Sound (Pierce, King, Snohomish and Kitsap) and a model that predicts future development to examine the extent to which high quality habitats have been impacted by past development and the extent to which they are likely to be compromised in the future. Future development was predicted for 3-year time steps from 2010 through 2050. The habitat capacity assessment indicated that high productivity areas are typically located in areas relatively proximate to salt water or along the floodplains of large rivers. These locations also are the areas where conversion from forest to development or agriculture has occurred most often in the past in the central Puget Sound region. Predicted future development will continue to be disproportionately focused in areas that currently support highly productive habitat