The California Wildlife Habitat Relationships (CWHR) system includes a habitat classification system and habitat suitability models for the approximately 650 species of terrestrial vertebrates that use these habitats. We created a computer model for grouping these species into guilds based on how the habitat suitability of forest-dwelling wildlife is predicted by CWHR to respond to changes in average tree diameter and percent forest canopy cover. We found that the largest bird guilds in Sierran mixed conifer habitat were: (1) species for which reproductive and cover habitat quality improved as average tree size increased; (2) species for which foraging habitat quality worsened as forest canopy cover increased; and (3) generalist species that showed no substantial change in habitat quality with respect to a particular life function as average tree size or forest canopy cover increased. We found that the predicted responses by the guilds from the model were generally consistent with several published lists enumerating species? sensitivities to habitat changes comparable to that modeled for the guilds. In conclusion, we suggest that our model may provide a useful tool for elucidating general biodiversity patterns in cumulative impacts and landscape resource assessments.
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