Quantifying aspects of rangeland health at watershed scales in Colorado using remotely sensed data products

Abstract

During grazing permit renewals, the Bureau of Land Management assesses land health using indicators typically measured using field-based data collected from individual sites within grazing allotments. However, agency guidance suggests assessments be completed at larger spatial scales. We explored how the current generation of remotely sensed data products could be used to quantify aspects of land health at watershed scales in Colorado to provide broad spatial and temporal context for the land health assessment process. We found multiple indicators could be quantified using these data products and were relevant to land health standards. Within focal watersheds, bare ground cover decreased over the past 30 years, while annual herbaceous cover has increased over the last 10 years. Vegetation productivity was variable over time, but interannual fluctuations were consistent across watersheds. Remotely sensed data products can help resource managers understand how current conditions relate to broad spatial and temporal trends in the region and could provide another line of evidence for the land health assessment process. They may also identify target areas where management strategies, such as eradication of invasive annual grasses, should be focused, and could help resource managers communicate complex issues to the public.