Impacts of outdoor recreation on multiple levels of a fragmented sagebrush-steppe ecosystem

Background/Question/Methods

Multiple-use public lands are important areas for conservation and human use, including outdoor recreation. In the western United States recreational use is growing rapidly, making it increasingly difficult to balance human use and enjoyment of the landscape with the conservation of wildlife populations that rely on the same areas. To better understand the impact of recreational use on conservation goals, we considered how the intensity of recreation impacts its effects on wildlife and how the effects of recreational use compare to other factors. We examined the impact of outdoor recreation on multiple levels of a sagebrush-steppe ecosystem in southwest Idaho. We selected sites that varied in the amount of recreational use and vegetation composition, then measured the abundance of Piute ground squirrels (Urocitellus mollis), abundance of raptors and common ravens (Corvus corax), density of mammalian scavengers, and density and nest success of ground-nesting birds at each site. We conducted weekly observational surveys of recreational use, then mapped the intensity of recreation using a Gaussian kernel density estimate to create a spatially and temporally informed recreational intensity variable. We assessed the effect of recreational intensity on each ecological variable relative to the effects of vegetation and landscape features.

Results/Conclusions

We found that recreational intensity had a positive effect on ground squirrel abundance, but native shrub cover had twice as great of an effect. Recreational intensity and other human features on the landscape, including power lines and development, had similarly strong positive effects on raven abundance. Raptor abundance did not have strong evidence for a relationship with recreation intensity, but there was moderate evidence of differences in the relationship depending on raptor species. Mammalian scavengers did not show a strong relationship with recreation intensity. Ground-nesting bird breeding density and nesting success showed negative relationships with recreation intensity, with more sensitive species exhibiting greater negative effects. Together these findings highlight the differences in outdoor recreation depending on a species life history, habitat requirements, and susceptibility to disturbance. Assessing multiple key species and considering the intensity of recreational use helped us gain a broader understanding of the effects of recreation in this ecosystem and provided information that can be used to support the coexistence of recreation and conservation on public lands.