Type: dissertation/thesis

Article abstract: Regional conservation planning is often guided by the use of focal species, whose persistence can serve as a measure of the habitat elements to be maintained or enhanced by conservation action. Here, I investigated the ecology of the American badger (Taxidea taxus) as a focal species for regional conservation planning in California. First, I investigated home range size and habitat use of nine radio-implanted badgers. At the study site scale, home ranges were sited in grasslands, sandy/loamy soil types, and close to recreational trails. Within their home range, badgers showed only a preference for intermediate slopes over very steep slopes. Dens within badgers' home range were associated with native grassland and scrub habitat, showed an avoidance of flat slopes, and tended to be found within 500 meters of trails. Second, I examined the fine-scale movement patterns of American badgers. Travel speeds were greater during the mating season and spring than they were in the winter for both sexes. Vegetation type affected the travel speed of males during the fall and spring; however, travel speed during the mating season was not affected by vegetation type. Finally, I used occurrence data to identify landscape factors affecting the population distribution of American badgers in California, and to examine the factors associated with declines in badger occurrences over time. Environmental features associated with badger occurrences and declines varied by ecoregion: an association with grassland and shrub cover was detected in some ecoregions, while an association with forest and woodland habitat was detected in others. In remote ecoregions, human-altered habitats were positively associated with badger occurrences. Declines in badger occurrences were associated with human-altered landscapes in two ecoregions. These results will inform conservation planning by 2 identifying 1.) area requirements for badgers, 2.) characteristics of habitat necessary for their behavioral activities, and 3.) factors that may affect corridor efficacy in badger habitat. Results also establish the geographic extent to which badgers should be considered in regional conservation plans, and identify habitat factors specific to each ecoregion that may affect badger persistence and thus their role as a focal species.