CSS is conducting Rapid Ecoregional Assessments (REAs) of the Colorado Plateau (COP) and Sonoran Desert (SOD) Ecoregions for the Bureau of Land Management (BLM). The REAs are designed to identify, assemble, synthesize, and integrate existing information about conservation elements (CEs), which include native species, aquatic resources, and terrestrial resources and how they may be affected by environmental change agents (CAs). CAs are disturbances on the landscape that can influence ecosystem health, and can include natural causes such as fire, or human caused disturbances such as development, or can result from the interaction of both, such as climate change. The REAs allow the BLM to better understand resource status and the potential for change from a broad viewpoint, and to assist with implementation of its land management responsibilities, including planning land use, developing best-management practices, authorizing uses, and establishing conservation and restoration priorities. CSS conducted an assessment of several hundred government and private sector data sets relevant to the SOD and COP ecoregions, evaluated their quality and efficacy, and then subsequently applied data to model the current status of each ecoregion. Models were evaluated by stakeholders through webinars and workshops, prior to incorporation into the final Rapid Ecoregional Assessments.