Sensitivities of sage‐grouse to weather and climate: Implications for indicator species in a moisture‐limited ecosystem

Abstract

Sage‐grouse ( Centrocercus spp.) are considered an indicator species for sagebrush ecosystems but are declining range‐wide, resulting from a suite of anthropogenic threats that are reducing habitat availability and quality throughout the sagebrush biome. Climate change is widely expected to exacerbate existing stressors and impose additional negative effects on wildlife populations. However, increasingly arid and extreme weather conditions may influence sage‐grouse population dynamics via numerous mechanisms including direct, indirect, and nonlinear (curvilinear, interactive, and antagonistic) effects, such that the net effects on population trends are difficult to anticipate and the most effective mitigation measures remain unclear. An improved understanding of how sage‐grouse are affected by weather and currently adapted to climate can help inform how their populations might be affected by predicted climate change and to maximize the effective use of conservation resources under future conditions. We reviewed, summarized, and synthesized all available literature regarding the direct and indirect effects of weather and climatic factors on sage‐grouse demography and population dynamics. We also provide a brief overview of how predicted future climate conditions may alter sagebrush ecosystems. Finally, we synthesize the results of our literature review to identify management strategies that may maximize future sage‐grouse population performance and persistence. Vegetation and plant communities in the semi‐arid sagebrush biome are already water‐limited, and the availability of soil moisture mediates many of the responses of sage‐grouse to variation in weather and climatic factors. Sage‐grouse are also subject to direct physiological effects of extreme weather conditions, via exposure, hypothermia, and possibly heat stress, although these effects have been less well‐documented. However, the indirect habitat‐mediated effects of weather and climatic factors may be more consequential for future sage‐grouse persistence and more amenable to management interventions. Management strategies that maintain and restore hydrological integrity may represent a key strategy for mitigating changing temperature and precipitation regimes that are likely to affect sage‐grouse. Specifically, managing for improved soil water infiltration and retention and the maintenance of diverse habitat mosaics may help mitigate drought effects on habitat conditions while also allowing sage‐grouse to access microclimates and more easily offset any increasing physiological stress imposed by future weather conditions.