Environmental Characteristics of Fuel Breaks for Analyzing Resistance to Annual Grass Invasion

Wildfire is an increasingly important driver of changes within sagebrush (Artemisia spp.) ecosystems of the western United States, often resulting in increased spread of exotic annual grasses, such as cheatgrass (Bromus tectorum), and subsequent losses of native vegetation and wildlife habitat. Fuel breaks, areas of land treated to reduce or redistribute hazardous fuels, are widely implemented to help prevent the spread of wildfires and provide areas to facilitate firefighting efforts. However, localized installation and maintenance of fuel breaks directly reduces or removes vegetation and may propagate the spread of exotic annual grasses into fuel break boundaries and surrounding areas, weakening ecological resilience to disturbance. These data supported investigation of exotic annual grass cover in association with fuel breaks across the sagebrush biome using multiple data sources, including targeted field surveys, land-management agency monitoring data, and remotely sensed vegetation cover data products, using space-for-time substitution within a Progressive-Change Before-After Control-Impact (PC BACI) study design, which accounted for confounding effects of roads. The data include measurements of exotic annual grass cover at survey locations performed by the Bureau of Land Management Assessment, Inventory, and Monitoring (AIM) program, field measurements of exotic annual grass cover collected at designated fuel breaks and control sites performed by the U.S. Geological Survey, and remotely sensed measurements of exotic annual grass and forb cover collected at field survey locations. Each set of data is accompanied by multiple environmental covariates used to characterize the ecosystem within which the analyses were conducted.