This map depicts the 825 terrestrial ecoregions of the globe. Ecoregions are relatively large units of land containing distinct assemblages of natural communities and species, with boundaries that approximate the original extent of natural communities prior to major land-use change. This comprehensive, global map provides a useful framework for conducting biogeographical or macroecological research, for identifying areas of outstanding biodiversity and conservation priority, for assessing the representation and gaps in conservation efforts worldwide, and for communicating the global distribution of natural communities on earth. We have based ecoregion delineations on hundreds of previous biogeographical studies, and refined and synthesized existing information in regional workshops over 10 years to assemble the global dataset. Ecoregions are nested within two higher-order classifications: biomes (14) and biogeographic realms (8). Together, these nested classification levels provide a framework for comparison among units and the identification of representative habitats and species assemblages. Ecoregions have increasingly been adopted by research scientists, conservation organizations, and donors as a framework for analyzing biodiversity patterns, assessing conservation priorities, and directing effort and support (Ricketts et al. 1999a; Wikramanayake et al. 2001; Ricketts et al. 1999b; Olson & Dinerstein 1998; Groves et al. 2000; Rosenzweig et al. 2003; and Luck et al. 2003). More on the approach to ecoregion mapping, the logic and design of the framework, and previous and potential uses are discusses in Olson et al. (2001) and Ricketts et al. (1999a). Groves, C., L. Valutis, D. Vosick, B. Neely, K. Wheaton, J. Touval, and B. Runnels. 2000. Designing a Geography of Hope: A practitioner's handbook to ecoregional conservation planning. The Nature Conservancy, Arlington, VA. Luck, G.W., T.H. Ricketts, G.C. Daily, M. Imhoff (2003). Spatial conflict between people and biodiversity. Procedings of the National Academy of Sciences - US. 101(1):182-186. Olson, D.M., and E. Dinerstein. 1998. The Global 200: a representation approach to conserving the Earth's most biologically valuable ecoregions. Conservation Biology 12:502-515. Olson, D.M., E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N. Powell, E.C. Underwood, J.A. D'Amico, I. Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, T.H. Ricketts, Y. Kura, J.F. Lamoreux, W.W. Wettengel, P. Hedao, and K.R. Kassem. 2001. Terrestrial ecoregions of the world: New map of life on earth. Bioscience 51(11):933-938. Ricketts, T.H., E. Dinerstein, D.M. Olson, C. Loucks. 1999. Who's where in North America? Patterns of species richness and the utility of indicator taxa for conservation. Bioscience 49(5):369-381. Ricketts, T.H., E. Dinerstein, D.M. Olson, C.J. Loucks, W. Eichbaum, K. Kavanagh, P. Hedao, P. Hurley, K.M. Carney, R. Abell, and S. Walters. 1999. Ecoregions of North America: A conservation assessment. Island Press. Washington DC. 485 pp. Rosenzweig, M.L., W. Turner, J.G. Cox, and T.H. Ricketts. 2003. Estimating diversity in unsampled habitats of a biogeographical province. Conservation Biology 17(3):864-874. Wikramanayake, E., E. Dinerstein, C. Loucks, D. Olson, J. Morrison, J. Lamoreux, M. McKnight, and P. Hedao. 2001. Terrestrial ecoregions of the Indo-Pacific: a Conservation assessment. Island Press, Washington, DC. Credits： Olson, D.M., E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N. Powell, E.C. Underwood, J.A. D’Amico, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, J.F. Lamoreux, T.H. Ricketts, I. Itoua, W.W. Wettengel, Y. Kura, P. Hedao, and K. Kassem. 2001. Terrestrial ecoregions of the world: A new map of life on Earth. BioScience 51(11):933-938. Use limitations： Any modification of the original map by users to ecoregion boundaries, units, names, or realm and biome classes must be noted.