Carnivores as focal species for conservation planning in the Rocky Mountain region

Viability analysis of well-selected focal species can complement ecosystem-level conservation planning by revealing thresholds in habitat area and landscape connectivity. Mammalian carnivores are good candidates for focal species because their distributional patterns often strongly reflect regional-scale population processes. We incorporated focal species analysis of four carnivore species, fisher (Martes pennanti), lynx (Lynx canadensis), wolverine (Gulo gulo), and grizzly bear (Ursus arctos), into a regional conservation plan for the Rocky Mountains of the United States and Canada. We developed empirical habitat models for fisher, lynx, and wolverine based on a geographically extensive data set of trapping and sighting records. Predictor variables derived directly from satellite imagery were significantly correlated with carnivore distribution and allowed us to predict distribution in areas lacking detailed vegetation data. Although we lacked similar distributional data for grizzly bear, we predicted bear habitat by adapting and extrapolating previously published, regional-scale habitat models. Predicted habitat for grizzly bear has high overlap with that for wolverine, intermediate overlap with fisher, and low overlap with lynx. High-quality habitats for fisher and lynx, unlike those for wolverine and grizzly bear, are not strongly associated with low levels of human population and roads. Nevertheless, they are naturally fragmented by topography and vegetation gradients and are poorly represented in existing protected areas. Areas with high biological productivity and low human impact are valuable habitat for all four species but are limited in extent. Predicted habitat values for lynx and wolverine are significantly correlated with trapping data from an area outside the extent of the original data set. This supports the use of empirical distribution models as the initial stage in a regional-scale monitoring program. Our results suggest that a comprehensive conservation strategy for carnivores in the region must consider the needs of several species, rather than a single, presumed umbrella species. Coordinated planning across multiple ownerships is necessary to prevent further fragmentation of carnivore habitat, especially in the U.S.-Canada border region.