Normalized least cost corridors, Columbia Plateau Analysis

This raster was clipped from the raw NLCC raster for this species according to the linkage width cutoff listed in Table 2.2 WHCWG (2012). As with the statewide analysis (see WHCWG 2010), the normalized least-cost corridor algorithms produced wall-to-wall linkage maps, with everygrid cell in the study area having a value that represented its deviation from the nearest least-cost movement route. This necessitated creating maps that displayed only values from zero (the optimum modeled route) to a species-specific linkage width cutoff to identify areas that contribute most to connectivity between each HCA pair. Because of the smaller extent of this analysis and the finer-scale data that were available, we chose cutoff values (Table 2.2, WHCWG 2012) that produced linkage zone widths that were somewhat narrower than those mapped at the statewide scale, while being mindful of the intent that linkage zones serve not only focal species, but other species and processes as well. Keeping linkage zones reasonably wide also acknowledges that there is still considerable uncertainty in GIS base data, resistance models, and other parameters used in our modeling process. We did not wish users of our products to assume that very narrow corridors necessarily indicate the areas most important for wildlife movement.