Spatial Ecology of Bobcats and Gray Foxes in Urban and Rural Zones of a National Park

摘要

Urbanization threatens the persistence of many wildlife populations, particularly those of wide-ranging and low-density species such as mammalian carnivores. Effective conservation of carnivore populations requires an understanding of the impacts of adjacent urbanization on carnivores in reserves. I compared the spatial ecology of bobcats (Lynx rufus) and gray foxes (Urocyon cinereoargenteus) between urban and rural zones of a national park in northern California, USA. In the urban zone, gray foxes used the entire landscape from interior natural areas across the park edges and into the neighboring developed areas, although fox core areas were always within the park. Bobcats never entered development, and radiocollared adult female bobcats maintained home ranges in the interior of the park, far from the urban edge. Bobcats appeared to avoid crossing paved roads, while foxes crossed roads regularly. For adult female bobcats, home ranges were smaller in the urban zone, and core areas were both smaller and overlapped more. Home range size and overlap did not differ between zones for gray foxes. Bobcats seem to be more affected by the proximity of urbanization than foxes, perhaps because of differences in diet and social structure. The more flexible use of the landscape by foxes may give them access to increased resources and habitat, but also may expose them to more human-associated risks. If female bobcats are more sensitive to urbanization, this sensitivity could affect the long-term viability of bobcat populations in urban areas. Knowledge of how bobcats and gray foxes use the landscape in urban areas will allow more effective conservation and improved coexistence with these widespread carnivores by helping to predict where and why conservation or management issues may occur.