Weekly Herbaceous and Exotic Annual Grass (EAG) Cover for western North America 2016 – 2026

For all available weekly RCMAP-EAG data see the RCMAP Viewer - Next Generation Viewer or MRLC for download. Two weeks of sample data and metadata are included below. 

Exotic species can disrupt ecosystems since they often possess competitive advantages over native species. In the western United States, the spread of exotic annual grasses (EAG) like cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae) has damaged wildlife habitats and reduced native species diversity across broad swathes of the landscape through its acceleration of the fire cycle. Application of remote sensing to capture the extent of EAG invasion across years enables managers to evaluate treatment success and strategize for defending and growing core (uninvaded) habitats. At the same time, finer temporal scale (weekly) classification of EAG cover empowers decision making on fire management and grazing. We have previously developed weekly maps of combined EAG cover for a set of common species and individual maps for especially challenging species using Harmonized Landsat Sentinel (HLS) imagery. Here, we describe major methodological improvements to the previous mapping method; 1) improved HLS composites, 2) additional training data and predictor variables, 3) expanding the temporal mapping window and study area, 4) training data association to a point in time instead of the seasonal curve, 5) post-processing, 6) product consistency, 7) an additional component, total herbaceous, and proper nesting of training data within the Rangeland Condition Monitoring Assessment and Projection (RCMAP) components, and 8) validation of the products with independent Analysis Inventory and Monitoring (AIM) observations. Commensurate with integration of EAG into the RCMAP cover component hierarchy, shared training data, and methods, the project names “EAG” and “Exotic Plant Monitoring System” will be retired in favor of “RCMAP-EAG”. The new generation of mapping products have been developed weekly for 2016-2026. Accuracy assessment compared to a set of 5,498 independent AIM observations yielded accuracy results of; total herbaceous (R² 0.75, RMSE 12.69%), total EAG (R² 0.61, RMSE 8.49%), cheatgrass (R² 0.61, RMSE 7.73%), medusahead (R² 0.45, RMSE 2.15%), field brome (R² 0.34, RMSE 3.21%), and Sandberg's bluegrass (R² 0.41, RMSE 6.00%). Weekly cover maps will be released in near-real-time during the growing season of February-September (week of year 10-37), in addition to historical weekly maps for 2016-present, with annual maps released following the completion of each mapping season.