Proactive management plans are required to protect populations of sensitive fish species from the cumulative impacts of logging and other landuse practices. Development of these plans requires information on the distribution and habitat use of fish species within the province. We surveyed stream sites in a watershed with high species diversity (the Blackwater), and developed statistical models based on macrohabitat variables to describe and predict fish species distributions. Eighty six percent of the variation in species richness at stream sites in the Blackwater drainage
was explained by drainage area, stream temperature, watershed gradient and distance to a lake. A similar, but much weaker, relationship with macrohabitat was observed for species richness in the Similkameen watershed. Correct classification rates of our logistic regression models based solely on map-based variables were generally high for most fish species found in the Blackwater (ranging from 73 to 90%), and showed only marginal improvements with inclusion of field-based information. The models correctly predicted the presence of individual species at stream sites 82.2% of the time (on average) when applied to an independent data set from the Blackwater drainage, but were much less successful when applied to data from a distant watershed (the Similkameen). Our analyses indicates that macrohabitat can be used to effectively describe fish species richness patterns and predict the regional distribution of individual species. Further refinements to quantify interregional variation in habitat conditions should allow the development
of fish distribution models for incorporation as a layer in B.C.?s Watershed Atlas. In conjunction with macrohabitat information available in the Watershed Atlas, distribution models could provide a powerful diagnostic and predictive tool for improved watershed planning and management in British Columbia.
Porter, M., Rosenfeld, J.; Parkinson, E.. 1998. Macrohabit Use and Predictive Models of Fish Distribution in the Blackwater Drainage. Ministry of Fisheries, Research and Development Section. Fisheries Management Report. 108