PS 15-111
Wildlife connectivity from the Central Valley to the Sierra Nevada Mountains
Habitat connectivity is important for wildlife to find food, cover and mates. Threats to habitat connectivity include roads, development, and habitat conversion. The northern Sierra Nevada foothills (NSNF) ecoregion represents an important area of connectivity across an elevation gradient between the low elevations of the Central Valley and the mountains of the Sierra Nevada but is threatened by urban sprawl. The foothills provide key habitat areas for wildlife such as mule deer that migrate seasonally between high and lower elevations and the oak woodlands also provide an important food source for many species ranging from birds, to rodents, to large mammals. To better understand habitat connectivity across the foothills we modeled fine-scale connectivity within the NSNF and between the NSNF and adjacent lands in the Central Valley and Sierra Nevada. We identified 30 focal species and used species-specific data to model habitat suitability and corridors between landscape blocks representing protected lands. The models identified important habitat patches for all focal species as well as least-cost habitat corridors for the passage species. We then combined the habitat corridors and habitat patches to build a linkage for each connection that represents move-through habitat for passage species and live-in habitat for corridor dwellers.
Results/Conclusions
We identified 246 linkages connecting 271 landscape blocks, with 848 individual species habitat corridors. The habitat corridors were based on species specific habitat models and consisted of 54 black bear (Ursus americanus) corridors, 105 black-tailed jackrabbit (Lepus californicus) corridors, 100 bobcat (Lynz rufus) corridors, 101 dusky-footed woodrat (Neotoma fuscipes) corridors, 85 gray fox (Urocyon cinereoargenteus) corridors, 66 mountain lion (Puma concolor) corridors, 154 mule deer (Odocoileus hemionus) corridors, 99 Western gray squirrel (Sciurus griseus) corridors and 84 Western pond turtle (Actinemys marmorata) corridors, with many species corridors overlapping. The linkage network connected species to protected lands throughout the foothills and surrounding ecoregions with each linkage providing habitat for at least seven species and up to 26 species. The mean number of species represented by the linkages was 16. The linkage network identified areas of high habitat suitability and also areas of conservation concern such as barriers to movement and movement bottlenecks. We envision these habitat linkages to be used for local and regional land-use planning, land use decision-making, conservation and habitat acquisition planning for state and local governments and conservation organizations.