ABSTRACT
Mapping suitable habitat is an important process in wildlife conservation planning. Species distribution reflects habitat selection processes occurring across multiple spatio-temporal scales. Because habitat selection may be driven by different factors at different scales, conservation planners require information at the scale of the intervention to plan effective management actions. Previous research has described habitat selection processes shaping the distribution of greater sage-grouse (Centrocercus urophasianus; sage-grouse) at the range-wide scale. Finer-scale information for applications within jurisdictional units inside the species range is lacking, yet necessary, because state wildlife agencies are the management authority for sage-grouse in the United States. We quantified seasonal second-order habitat selection for sage-grouse across the state of Utah to produce spatio-temporal predictions of their distribution at the southern periphery of the species range. We used location data obtained from sage-grouse marked with very-high-frequency radio-transmitters and lek location data collected between 1998 and 2013 to quantify species habitat selection in relation to a suite of topographic, edaphic, climatic, and anthropogenic variables using random forest algorithms. Sage-grouse selected for greater sagebrush (Artemisia spp.) cover, higher elevations, and gentler slopes and avoided lower precipitations and higher temperatures. The strength of responses to habitat variables varied across seasons. Anthropogenic variables previously reported as affecting their range-wide distribution (i.e., roads, powerlines, communication towers, and agricultural development) were not ranked as top predictors at our focal scale. Other than strong selection for sagebrush cover, the responses we observed differed from what has been reported at the range-wide scale. These differences likely reflect the unique climatic, geographic, and topographic context found in the southern peripheral area of the species distribution compared to range-wide environmental gradients. Our results highlight the importance of considering appropriateness of scale when planning conservation actions for wide-ranging species.
ABSTRACT
Climate change has been implicated as a root cause of the recent surge in natural disturbance events such as storms, wildfires, and insect outbreaks. This climate-based surge has led to a greater focus on disturbance-mitigating benefits of ecosystem management. Quantifying these benefits requires knowledge of the relationship between natural and anthropogenic disturbances, which is lacking at the temporal and spatial scales needed to inform ecosystem-based management. This study investigates a specific relationship between timber harvesting and climate-amplified outbreaks of mountain pine beetle. If harvesting is located to mitigate long-distance insect dispersal, there is potential for a win-win outcome in which both timber production and forest conservation can be increased. This spatially targeted harvesting strategy lowers the cost of providing disturbance-mitigating ecosystem services, because valuable timber products are also produced. Mitigating long-distance dispersal also produces net gains in forest conservation across various stakeholder groups. These results speak to ongoing federal efforts to encourage forest vegetation removal on public forestlands to improve forest health. These efforts will lower the cost of responding to climate-amplified natural disturbance events but only if vegetation removal efforts are spatially located to reduce disturbance risk. Otherwise, efforts to improve forest health may be converting forest conservation services to timber services.
