Ecoregion-Based Conservation Assessments of the SW United States and Northwestern Mexico

Abstract

In 1995, The Nature Conservancy introduced ecoregional assessments—a science-based framework for identifying conservation priorities across large ecological regions defined by natural features rather than political boundaries. Between 1999 and 2004, six assessments were completed for the southwestern U.S. and northwestern Mexico, covering 238 million acres and analyzing over 1300 species and 350 native plant communities. To overcome jurisdictional fragmentation and data incompatibility, the assessments were standardized into a unified “six-ecoregion geodatabase,” enabling cross-boundary conservation planning. The resulting network of 100 million acres, mostly on federal lands, highlights areas critical to preserving biodiversity amid growing threats like habitat loss, water scarcity, and climate change. This integrated dataset supports ecosystem-based management and helps agencies, planners, and conservationists coordinate efforts, evaluate land-use compatibility, and promote natural disturbance regimes to sustain healthy ecosystems and reduce future endangered species listings.

Additional Resources

Ecoregional Assessment GIS Data

Citation

Marshall, R., M. List, and C. Enquist. 2006. Ecoregion-Based Conservation Assessments of the Southwestern United States and Northwestern Mexico:  A Geodatabase for Six Ecoregions, Including the Apache Highlands, Arizona-New Mexico Mountains, Colorado Plateau, Mojave Desert, Sonoran Desert, and Southern Rocky Mountains.  Prepared by The Nature Conservancy, Tucson, AZ. 37 pp