Habitat use by mammals varies along an exurban development gradient in northern Colorado

Exurban development, defined as residential development outside of cities and towns, occupies nearly five times more land in the United States than urban and suburban development combined. Understanding the effects of exurban development on biodiversity thus has important and wide-ranging implications for the planning, construction and stewardship of sustainable communities and surrounding rural lands. To assess the impact of exurban development on mammalian habitat use, wildlife cameras were placed along a unique gradient of landscape permeability through varying densities and configurations of housing development in a rapidly growing rural region of Colorado. Multiple-season species occupancy and relative activity levels were measured in summer and winter seasons. The impacts of exurban housing on mammals were species specific and varied along the development gradient. Bobcats (Lynx rufus), elk (Cervus canadensis), and coyotes (Canis latrans), showed decreased activity and occupancy levels in more developed areas, whereas red foxes (Vulpes vulpes) occurred more frequently in these areas. Other species did not show significant responses to exurban development. In addition, black bears (Ursus americanus) used embedded greenbelts more frequently in high-density exurban subdivisions. Using our development gradient provides ecologically relevant insight into how mammals respond to residential development, and our results demonstrate that some species respond positively to residential development, but that others decline or disappear as the development gradient intensifies. Incorporating well-designed and naturally vegetated open spaces into development projects and minimizing human disturbance could mitigate impacts to mid-large sized mammals in regions undergoing exurban