Climate change amplifies ongoing declines in sagebrush ecological integrity

Authors: HOLDREGE, MARTIN - Us Geological Survey (USGS); PALMQUIST, KYLE - Marshall University; SCHLAEPFER, DANIEL - Us Geological Survey (USGS); LAUENROTH, WILLIAM - Yale University; Boyd, Chad; CREUTZBURG, MEGAN - Oregon State University; CRIST, MICHELE - Bureau Of Land Management; DOHERTY, KEVIN - Us Fish And Wildlife Service; REMINGTON, THOMAS - Western Association Of Fish And Wildlife Agencies; TULL, JOHN - Western Association Of Fish And Wildlife Agencies; WIECHMAN, LIEF - Us Fish And Wildlife Service; BRADFOR, JOHN - Us Geological Survey (USGS)

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2024
Publication Date: 10/15/2024
Citation: Holdrege, M.C., Palmquist, K.A., Schlaepfer, D.R., Lauenroth, W.K., Boyd, C.S., Creutzburg, M.K., Crist, M.R., Doherty, K.E., Remington, T.E., Tull, J.C., Wiechman, L.A., Bradfor, J.B. 2024. Climate change amplifies ongoing declines in sagebrush ecological integrity. Rangeland Ecology and Management. 97:25-40. https://doi.org/10.1016/j.rama.2024.08.003.
DOI: https://doi.org/10.1016/j.rama.2024.08.003

Interpretive Summary: Understanding how climate change will contribute to ongoing changes in sagebrush ecological integrity is critical for informing natural resource management, yet complicated by interactions with wildfire and biological invasions. Here, we assessed potential future changes in sagebrush ecological integrity under a range of scenarios using an individual plant-based simulation model, integrated with remotely sensed estimates of current sagebrush ecological integrity. The most common projected transitions in sagebrush habitat classification were declines from Core Sagebrush Area to Growth Opportunity Area and from Growth Opportunity Area to Other Rangeland Areas, but responses varied considerably across projections from different global climate models, highlighting the importance of climate uncertainty. Our results provide a long-term perspective on the vulnerability of sagebrush ecosystems to climate change, may inform geographic prioritization of conservation and restoration investments, and will aid in proactive management to mitigate climate effects on sagebrush habitats.

Technical Abstract: Understanding how climate change will contribute to ongoing declines in sagebrush ecological integrity is critical for informing natural resource management, yet complicated by interactions with wildfire and biological invasions. We assessed potential future changes in sagebrush ecological integrity under a range of scenarios using an individual plant-based simulation model, integrated with remotely sensed estimates of current sagebrush ecological integrity. The simulation model allowed us to estimate how climate change, wildfire, and invasive annuals interact to alter the potential abundance of key plant functional types that influence sagebrush ecological integrity: sagebrush, perennial grasses, and annual grasses. Our results suggest that climate driven reductions in sagebrush ecological integrity may occur over broader areas than increases in sagebrush ecological integrity. Declines in sagebrush ecological integrity were most likely in hot and dry regions while increases were more likely in cool and wet regions. The most common projected transitions of sagebrush ecological integrity classes were declines from Core Sagebrush Area to Growth Opportunity Area and from Growth Opportunity Area to Other Rangeland Area. Responses varied considerably across projections from different global climate models, highlighting the importance of climate uncertainty. However, our projections tended to be robust in areas that currently have the highest sagebrush ecological integrity. Our results provide a long-term perspective on the vulnerability of sagebrush ecosystems to climate change and may inform geographic prioritization of conservation and restoration investments. The results also suggest that ongoing threats, such as the continued invasion by annual grasses and increased wildfire frequency, are likely to be amplified by climate change, and imply that the current imbalance between capacity for conservation to address threats to sagebrush will grow as the climate warms.