Time-Series Data
Rangeland managers need information on the current vegetation condition and how the landscape has changed through time. To address this need, scientists from the USGS and Bureau of Land Management (BLM) developed the Rangeland Condition Monitoring Assessment and Projection (RCMAP) project. U.S. rangelands are classified as fractional (0-100%) cover of ten ground cover components (annual herbaceous, bare ground, herbaceous, litter, non-sagebrush shrub, perennial herbaceous, sagebrush, shrub, and tree and shrub height). Maps are produced using Landsat imagery for each year in a time-series stretching from 1985-Current. This long-term perspective is key to understanding vegetation response to drought, invasive species, land management decisions, and disturbance. RCMAP time-series data enable retrospective analysis of vegetation condition, impacts of weather variation and longer-term climatic change, and understanding of vegetation treatment and altered management practice effectiveness. RCMAP also produces a series of trends analysis which depict the net changes in cover over the time-series in addition to highlighting significant change events (break points).
Exotic Annual Grass
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. The RCMAP-EAG dataset provides early estimates of fractional cover of several EAG species and one native perennial grass species on a weekly basis during the core growing season of early March-Early September. EAG maps are released within 7-10 days of the latest satellite observation used for that weekly map. Each weekly release contains eight fractional cover maps for: 1) total herbaceous, 2) green herbaceous, 3) senesced herbaceous, 4) a group of 15 species of EAGs (total EAG), 5) Cheatgrass (Bromus tectorum); 6) Combined cover of Field brome (Bromus arvensis) and Japanese brome (Bromus japonicus); 7) Medusahead (Taeniatherum caput-medusae); and 8) Sandberg’s Bluegrass (Poa secunda). In addition to weekly products, we derive annual data by obtaining the maximum cover value across weeks in a year by component.
Future Projections
RCMAP future projections include three time periods (2020s, 2050s, and 2080s) and two climate scenarios (Representative Concentration Pathways [RCP] 4.5 and 8.5). Future predictions are based on neural network models trained on annual weather conditions and component cover in the historical period (1985-2023) and applied to future climate data. Component projections are designed to be used individually or combined to support a broad variety of applications. Data are packaged by time-period and climate scenarios (six). Additionally, for comparison to reference conditions, a scenario based on 1991-2020 climate normal is available.
For more information see: https://www.usgs.gov/centers/eros/science/rangeland-condition-monitoring-assessment-and-projection-rcmap
For additional information on RCMAP product accuracy variation by ecoregion, cover value, and spatial scale, see here
