As the distribution and abundance of non-native cheatgrass (Bromus tectorum) in the Great Basin has increased, the extent and frequency of fire in the region has increased by as much as 200%. These changes in fire regimes are associated with loss of the sagebrush (Artemisia tridentata) and native grasses and forbs in which many native animals, including Greater Sage-Grouse (Centrocercus urophasianus; henceforth, sage grouse), breed and feed. Changes in fire regimes, fuels treatments, and post-fire restoration have been suggested with the intent of increasing the probability of sage-grouse persistence. However, the potential responses of other sensitive-status birds to these interventions have not been assessed rigorously.
This project will model current and future (to 2050) spatial interactions among cheatgrass cover and biomass, precipitation, and fire across the Great Basin and model current and future cover of sagebrush and herbaceous vegetation. For tractability, the analyses of percent cover of sagebrush and herbaceous vegetation, and of the habitat quality and occupancy of sensitive-status birds, will focus on three areas: the eastern Owyhee uplands (Idaho, Oregon, and Nevada), Bodie Hills-Pine Nut Mountains (California and Nevada), and east-central Great Basin (Nevada and Utah), each corresponding to the area covered by one Landsat scene (~185 x 185 km). These three areas span both biogeographic gradients and gradients of isolation and resilience of sage grouse.
The project team will examine how projected changes in fire regimes and fire and fuels treatments may affect habitat quality for and probability of occupancy of sensitive-status breeding birds. Additionally, they will use statistical change-point analyses to detect any abrupt, nonlinear temporal changes-thresholds-in projected vegetation cover, habitat quality, and occupancy. Detection of ecological thresholds, if they exist, may suggest fuels treatments and restoration actions that will decrease the probability of entering into or remaining within undesirable ecological states.
Project start date: 9/1/2015
Fiscal year funded: 2014
Project status: Active
Project managers: Erica Fleishman, John Muir Institute of the Environment, University of California, Davis; Jennifer Balch, University of Colorado, Boulder; Bethany Bradley, University of Massachusetts, Amherst; Todd Hopkins, Great Basin Landscape Conservation Cooperative; Ned Horning, American Museum of Natural History; Matthias Leu, College of William and Mary; Ralph Mac Nally, University of Canberra; Mike Pellant, Bureau of Land Management