Landscapes as a moderator of thermal extremes: a case study from an imperiled grouse

The impacts of climate driven change on ecosystem processes and biodiversity are pervasive and still not fully understood. Biodiversity loss, range shifts, and phenological mismatches are all issues associated with a changing climate that are having significant impacts on individuals and ecosystems alike. Investigating and identifying effective management strategies that can conserve vulnerable species should be the focus of current and future climate change research. We investigated thermal properties of habitat for an imperiled grouse (Greater Prairie-chicken; Tympanuchus cupido) in tallgrass prairie characterized by heterogeneous fire and grazing (the fire-grazing interaction). We examined operative temperature at varying scales relevant to grouse and used historic and forecasted climate data to estimate thermal stress during nesting activities. We found that heterogeneous grasslands have high thermal variability with operative temperature ranging as much as 238 degrees C across the landscape. Grouse exhibited strong selection for cooler thermal environments as nest sites were as much as 88 degrees C cooler than the surrounding landscape, and fine-scale differences in thermal environments were nearly 48 degrees C cooler than sites within 2 m of nests. Additionally, forecasted climate scenarios indicate grouse will experience 2-4 times the number of hours above thermal stress thresholds, emphasizing the need for informed conservation management. Overall, these data provide evidence that variation in grassland structure resulting from the fire-grazing interaction may be important in moderating thermal environments and highlights the complex and interactive effects of restored ecological processes on ecosystems.