Monitoring Vegetation Change from Space
Disturbances such as livestock grazing, exotic species invasion, conversion to agriculture, urban expansion, energy development, and other development have altered and reduced sagebrush ecosystems by half since European settlement. It is crucial to understand the distribution of and variability in sagebrush habitat in order to understand current and future conditions in sagebrush systems. Habitat components, such as vegetation cover and shrub height, can provide a baseline for monitoring long-term changes in habitat conditions. Understanding the relations between habitat conditions and drivers of change, such as development and climate, is critical for understanding current and future distribution and characteristics of sagebrush habitats, as well as the locations and rates of change. However, measuring change on the ground can be expensive, time-consuming and labor-intensive.
USGS scientists have developed an affordable, repeatable set of protocols which serve as the cornerstone of sagebrush habitat monitoring in the WLCI region. Our approach entails combining field sampling data and remote sensing (satellite data) for estimating the percent cover of sagebrush, plant litter, and bare ground across the entire WLCI landscape. This work extends beyond traditional category-based cover-type mapping, focusing instead on making continuous cover predictions for sagebrush habitat characteristics at multiple spatial scales across the WLCI landscape. With repeated predictions over time, the USGS can evaluate and quantify the amount and distribution of change in sagebrush habitat features. This information is critical for understanding current and future distribution. Additionally, it provides input to a broad spectrum of WLCI research and applications, including projects associated with quantifying and monitoring sage grouse, pronghorn, and pygmy rabbit habitats.