NatureServe has worked with the National Gap Analysis Program to map existing vegetation using the U.S. National Vegetation Classification (USNVC) classification standard at the alliance level. Many state and regional GAP programs have needed to develop map units at scales that are intermediate between the alliance level and formation level. Since the USNVC provides no intermediate scale, ad-hoc map units have been developed in each state effort, impeding the ability to create consistent regional maps. Ecological systems present an alternative and consistent method to develop “meso-scale” vegetation-based units across a region. Ecological systems are linked to the USNVC and are defined as groups of plant associations from one or more USNVC alliances that occur together on a given landscape due to similarities in ecological dynamics, underlying environmental features, and/or environmental gradients. A study was initiated in the USFS Region 2 to classify and map ecological systems in that region, linking them to the original landcover maps created by five state GAP programs. This regional effort builds directly on national classification efforts, so units developed for this project are already part of a consistent national classification of ecological systems. The original maps were grouped to create a regional coverage and then, in many instances, combined with ancillary spatial data (ecoregions, elevation, landform, National Land Cover Data, hydrography, soils, etc.), recoded to reflect 61 upland and wetland ecological systems attributed to this region.
- Comer P, Menard S, Tuffly M, Kindscher K, Rondeau R, Jones G, Steinuaer G, Schneider R and Ode D. 2003. Upland and Wetland Ecological Systems in Colorado, Wyoming, South Dakota, Nebraska, and Kansas. Report and Map to the National Gap Analysis Program. (U.S. Geological Survey, Department of Interior). NatureServe, Arlington, Virginia. 18 pp. plus appendices.