Trends in Stream Habitat Conditions: A Thirteen Year Perspective from the Interior Columbia River Basin

We evaluated data collected over 13 years at over 1,000 stream reaches to determine the trend in habitat conditions in wadeable fish-bearing streams within federal lands of the interior Columbia River Basin.  Through the course of this study a suite of habitat metrics where measured in minimally managed (reference) and managed reaches.  Using a mixed model approach we evaluated whether habitat conditions at managed reaches are improving and/or moving towards reference conditions.  We utilized multiple physical and climatic covariates in order to better isolate their effects on habitat conditions.  Evaluating trend in both managed and reference streams allows for a better understanding of large scale patterns in stream habitat conditions.  Where trend patterns were similar between managed and reference reaches suggests that change was driven by natural landscape processes.  Where patterns were dissimilar suggest that land management actions were a causative factor.  Although federal management actions appear to be maintaining or improving habitat conditions, some exceptions exist.