Assessing Climate Change for Landscapes and Major Vegetation Types across the Inter-Mountain West

Working with the Bureau of Land Management, NatureServe ecologists are assessing climate change across the West. The objective of this effort is to identify trends in climate across the entire western conterminous United States, and given these trends, to assess the relative climate change vulnerabilities of major vegetation types that occur on BLM lands. Our research focuses initially on comparing current (as of 2014) climatology to historical climate variability (mid-20th century), providing a contextualized metric of climate change. This same framework applies to forecasting climate change vulnerability using climate projections over upcoming decades.

Historical climate variation occurs on multiple dimensions, including temporal (inter-annual variability) and biotic (variation across a vegetation type’s niche in environmental space). We interpret climate change through these different lenses, each of which contributes a distinct and ecologically relevant picture of exposure to climate change.

Habitat Climate Change Vulnerability Index (HCCVI) - NatureServe has developed a framework for gauging climate change vulnerability of individual types of natural communities or species habitats.

These assessments bring together data on exposure and resilience to measure and map climate change vulnerability across it full geographic range. Exposure includes changes in climate suitability – as an indication of climate stress - as compared to a mid-20th century baseline. Resilience measures address factors in response to climate exposure that could mitigate or exacerbate effect of climate stress. Measures for Resilience are categorized into Sensitivity and Adaptive Capacity. Sensitivity includes estimates of landscape intactness or condition, invasive species abundance, relative degree of natural wildfire regime alteration (e.g., through wildfire suppression, etc.), and elevated insect or disease risk in forests. Adaptive capacity includes estimates of natural diversity within functional species groups (e.g., nitrogen fixing plants, seed dispersing animals), relative vulnerability of any apparent “keystone” species (e.g., prairie dogs), and topoclimatic variability, or the microclimate variability naturally occurring due to rugged vs. flat topography.

Through this effort, we have assessed 52 major upland vegetation types occurring on BLM lands, including major sagebrush, warm desert scrub, grasslands, pinyon-juniper, and montane forest types.

Relative climate change vulnerability, along with scores for component factors, is summarized in spatial and tabular formats and results vary across the range of each type. Most types score as moderate vulnerability under current climate condition, but shift to high vulnerability toward the mid-21st century. Results from component measures support the identification of adaptive management strategies suitable for implementation over the upcoming decades.

Given the scope of BLM land management across the western U.S., and their ongoing processes for assessment, planning, vegetation management, and monitoring, it is critical to find effective ways to share information, enhance understanding, and facilitate the collaboration by professionals, stakeholders, and the engaged public. The associated Map Galleries provide access to maps, tables, and documents associated with this effort.