Ecological Potential Fractional Component Cover Based on Long-Term Satellite Observations Across the Western United States

Rangelands have immense inherent spatial and temporal variability, yet assessments of land condition and trends are often assessed relative to the condition of a limited number of representative points. Ecological Potential (EP) data are spatially comprehensive, quantitative, and needed as a baseline for comparison of current rangeland vegetation conditions, trends, and management targets. We define EP as the potential fractional cover of vegetation components bare ground, herbaceous, litter, shrub, and sagebrush represented in the least disturbed and most productive portion of the western U.S. This dataset enables: 1) setting realistic expectations for restoration and management targets at 30-meter resolution, 2) better understanding of the extent of vegetation departure from potential and 3) improved spatial understanding of vegetation composition and productivity variation. We produce EP maps across rangelands in the Western U.S. by training regression tree models in ecologically intact sites. The independent variables in these models include digital soils, topography data, six bimonthly composites of the 90th percentile of NDVI, and the associated spectral bands from the 1985-2018 Landsat archive. The study area encompasses all or part of 17 states and a vast range of biophysical conditions, vegetation conditions, and disturbance history. The region is 3,006,071 km2, of which 2,060,962 km2 was rangeland.