Developing a climate stress index to better manage wildlife in a changing climate

Background/Question/Methods

Vulnerability assessments are an initial step to inform the development of climate change adaptation options. Climate change will affect wildlife directly through temperature and moisture changes and indirectly through habitat availability as cover and land use changes. Recommendations to conserve wildlife resources under climate change will need to be integrated across administrative boundaries (e.g., States, Public lands, National Forests and Grasslands). A regionally consistent information base facilitates the collaboration necessary for managing wildlife species and their habitat. Our study focused on the coterminous United States, on an annual time frame, and at a 0.083 degree grid cell spatial scale. Three metrics were integrated into a single terrestrial climate stress index (TCSI) that quantified the degree of change between the recent history and projected futures in climate, vegetation productivity, and vegetation type area.  Future projections of biomass and shifts in types were obtained from the dynamic global vegetation model MC2 – a model capable of assessing the impacts of climate change, disturbance (fire, drought), and biogeochemistry on ecosystems. To account for uncertainty, we considered a total of 18 different realizations of future climate and vegetation characteristics: three IPCC scenarios, three climate models, and two fire management scenarios.

Results/Conclusions

The TCSI was used to identify areas of relatively high and low habitat stress across the coterminous U.S.  The most sensitive terrestrial areas are associated with transitions between major biomes and areas of high topographic relief. Areas most exposed to habitat stress occur along grassland-forestland transitions and steep elevation gradients in the intermountain west.  TCSI score variability was generally low in high stress areas and high in low stress areas. Such information can provide practitioners with information on potential climate-induced stress to wildlife habitats within regions and states. Further, the potential impacts of climate change on wildlife are multiple and interacting. Spatially explicit information on habitat stress attributed to climate change can be integrated with the location of current stressors (e.g., concentrations of intensive land uses that could affect wildlife movements) to evaluate the coincidence of future climate change threats with existing threats to wildlife resources. Linking changes in habitat to changes in climate provides a template for decision makers to evaluate potential risks to wildlife resource attributable to climate change across landscapes.