Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental poster is part of a collaborative project primarily between the USEPA National Health and Environmental Effects Griffith, G.E., Omernik, J.M., Wilton, T.F., and Pierson, S.M., 1994, Ecoregions and subregions of Iowa - a framework for Griffith, G.E., Omernik, J.M., Wilton, T.F., and Pierson, S.M., 1994, Ecoregions and subregions of Iowa - a framework for resources; they are designed to serve as a spatial framework for the research, assessment, management, and Research Laboratory - Corvallis, OR., and TDEC’s Division of Water Pollution Control. Collaboration and water quality assessment and management: The Journal of the Iowa Academy of Science, v. 101, no. 1, p. 5-13. water quality assessment and management: The Journal of the Iowa Academy of Science, v. 101, no. 1, p. 5-13. consultation also occurred with the United States Department of Agriculture - Natural Resources Conservation monitoring of ecosystems and ecosystem components. Ecoregions are directly applicable to the immediate needs Griffith, G.E., Omernik, J.M., and Azevedo, S.H., 1997, Ecoregions of Tennessee: Corvallis, Oregon, U.S. Environmental Griffith, G.E., Omernik, J.M., and Azevedo, S.H., 1997, Ecoregions of Tennessee: Corvallis, Oregon, U.S. Environmental of state agencies, such as the Tennessee Department of Environment and Conservation (TDEC), for selecting Service (NRCS), the United States Department of Agriculture - Forest Service (USFS), USEPA Region IV, and Protection Agency EPA/600R-97/022, 51 p. Protection Agency EPA/600R-97/022, 51 p. regional stream reference sites and identifying high-quality waters, developing ecoregion-specific chemical and with other State of Tennessee agencies. biological water quality criteria and standards, and augmenting TDEC’s watershed management approach. Omernik, J.M., 1987, Ecoregions of the conterminous United States (map supplement): Annals of the Association of Omernik, J.M., 1987, Ecoregions of the conterminous United States (map supplement): Annals of the Association of This project is associated with an interagency effort to develop a common framework of ecological regions. American Geographers, v. 77, no. 1, p. 118-125, scale 1:7,500,000. American Geographers, v. 77, no. 1, p. 118-125, scale 1:7,500,000. Ecoregion frameworks are also relevant to integrated ecosystem management, an ultimate goal of most federal and Reaching that objective requires recognition of the differences in the conceptual approaches and mapping state resource management agencies. methodologies that have been used to develop the most commonly used existing ecoregion-type frameworks, Omernik, J.M., 1995, Ecoregions - a framework for environmental management, in Davis, W.S. and Simon, T.P., eds., Omernik, J.M., 1995, Ecoregions - a framework for environmental management, in Davis, W.S. and Simon, T.P., eds., Biological assessment and criteria - tools for water resource planning and decision making: Boca Raton, Florida, Lewis Biological assessment and criteria - tools for water resource planning and decision making: Boca Raton, Florida, Lewis including those developed by the USFS (Bailey et al. 1994), the USEPA (Omernik 1987, 1995), and the NRCS The approach used to compile this map is based on the premise that ecological regions can be identified through Publishers, p. 49-62. Publishers, p. 49-62. the analysis of the patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in (U.S. Department of Agriculture 1981). As each of these frameworks is further developed, the differences ecosystem quality and integrity (Wiken 1986; Omernik 1987, 1995). These phenomena include geology, between them lessen. Regional collaborative projects such as this one in Tennessee, where some agreement can U.S. Department of Agriculture - Soil Conservation Service, 1981, Land resource regions and major land resource areas of the U.S. Department of Agriculture - Soil Conservation Service, 1981, Land resource regions and major land resource areas of the physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each be reached among multiple resource management agencies, is a step in the direction of attaining commonality and United States: Agriculture Handbook 296, 156 p. United States: Agriculture Handbook 296, 156 p. characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral consistency in ecoregion frameworks for the entire nation. U.S. Environmental Protection Agency, 1997, Level III ecoregions of the continental United States (revision of Omernik, U.S. Environmental Protection Agency, 1997, Level III ecoregions of the continental United States (revision of Omernik, hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, Literature Cited: 1987): Corvallis, Oregon, U.S. Environmental Protection Agency - National Health and Environmental Effects Research 1987): Corvallis, Oregon, U.S. Environmental Protection Agency - National Health and Environmental Effects Research dividing North America into 15 ecological regions, with level II dividing the continent into 52 regions. At level Laboratory Map M-1, various scales. Laboratory Map M-1, various scales. III, the continental United States contains 99 regions (United States Environmental Protection Agency [USEPA] Bailey, R.G., Avers, P.E., King, T., and McNab, W.H., eds., 1994, Ecoregions and subregions of the United States (map) (supplementary table of map unit descriptions compiled and edited by McNab, W.H. and Bailey, R.G.): Washington, D.C., Wiken, E., 1986, Terrestrial ecozones of Canada: Ottawa, Environment Canada, Ecological Land Classification Series no. 19, Wiken, E., 1986, Terrestrial ecozones of Canada: Ottawa, Environment Canada, Ecological Land Classification Series no. 19, 1997). Level IV is a further subdivision of level III ecoregions. Explanations of the methods used to define U.S. Department of Agriculture - Forest Service, scale 1:7,500,000. 26 p.of map unit descriptions compiled and edited by McNab, W.H. and Bailey, R.G.): Washington, D.C., U.S. Department of 26 p. USEPA’s ecoregions are given in Omernik (1995), Griffith et al. (1994, 1997), and Gallant et al. (1989). Agriculture - Forest Service, scale 1:7,500,000. Gallant, A.L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing This level III and IV ecoregion map was compiled at a scale of 1:250,000; it depicts revisions and subdivisions of environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency EPA/600/3-89/060, 152 p. Gallant, A.L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing earlier level III ecoregions that were originally compiled at a smaller scale (USEPA 1996; Omernik 1987). The environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency EPA/600/3-89/060, 152 p.
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90° 89° 88° 87° 86° 85° 84° 83° INTERIOR—G EOLOG ICAL S U RVEY, RES TON, VIRG INIA—1998 82° Level III Ecoregions of the Conterminous United States 1 Coast Range 27 Central Great Plains 54 Central Corn Belt Plains 2 Puget Lowland 28 Flint Hills 55 Eastern Corn Belt Plains 77 3 Willamette Valley 1 2 29 Central Oklahoma/Texas Plains 56 Southern Michigan/Northern Indiana 41 4 Cascades 30 Edwards Plateau Drift Plains 42 65 Southeastern Plains 67 Ridge and Valley 69 Central Appalachians 73 Mississippi Alluvial Plain SCALE 1:940 000 10 5 Sierra Nevada 31 Southern Texas Plains 48 49 58 57 Huron/Erie Lake Plains 3 16 6 Southern and Central California 1 15 32 Texas Blackland Prairies 58 Northeastern Highlands 65a Blackland Prairie 67f Southern Limestone/Dolomite 69d Cumberland Mountains 73a Northern Mississippi Alluvial Plain 10 0 20 40 mi Chaparral and Oak Woodlands 11 33 East Central Texas Plains 59 Northeastern Coastal Zone 16 43 4 15 16 50 58 7 Central California Valley 34 Western Gulf Coastal Plain 60 Northern Appalachian Plateau 65b Flatwoods/Alluvial Prairie Margins Valleys and Low Rolling Hills 17 17 51 51 50 8 Southern California Mountains 9 12 46 35 South Central Plains and Uplands 20 0 40 80 km 17 9 Eastern Cascades Slopes and 36 Ouachita Mountains 78 57 60 62 59 61 Erie/Ontario Drift and Lake Plains 65e Southeastern Plains and Hills 67g Southern Shale Valleys 52 53 Foothills 37 Arkansas Valley 71 Interior Plateau 74 Mississippi Valley Loess Plains Albers equal area projection 56 62 62 North Central Appalachians 18 10 Columbia Plateau 38 Boston Mountains 65i Fall Line Hills 67h Southern Sandstone Ridges 44 47 57 61 67 63 Middle Atlantic Coastal Plain 71e Western Pennyroyal Karst 74a Bluff Hills Standard parallels 35° 20' N and 36° 15' N 13 19 64 63 11 Blue Mountains 39 Ozark Highlands 5 54 64 Northern Piedmont 25 55 70 65j Transition Hills 67i Southern Dissected Ridges and 1 12 Snake River Basin/High Desert 40 Central Irregular Plains 65 Southeastern Plains 7 71f Western Highland Rim 74b Loess Plains 21 27 13 Northern Basin and Range 41 Canadian Rockies* 66 Blue Ridge Mountains 20 40 Knobs 8 28 69 14 Southern Basin and Range 42 Northwestern Glaciated Plains 67 Ridge and Valley 71g Eastern Highland Rim 6 72 15 Northern Rockies 43 Northwestern Great Plains PRINCIPAL AUTHORS: Glenn Griffith (USEPA), James Omernik (USEPA) and 39 71 68 Southwestern Appalachians 8 16 Montana Valley and Foothill 44 Nebraska Sand Hills 66 Blue Ridge Mountains 22 67 45 69 Central Appalachians 71h Outer Nashville Basin Sandra Azevedo (OAO Corporation). 14 26 Prairies 38 66 45 Piedmont* 70 Western Allegheny Plateau 6 63 66d Southern Igneous Ridges and Mountains 68 Southwestern Appalachians 37 17 Middle Rockies 46 Northern Glaciated Plains 71i Inner Nashville Basin 23 36 73 71 Interior Plateau 68 18 Wyoming Basin 47 Western Corn Belt Plains 72 Interior River Lowland 66e Southern Sedimentary Ridges 68a Cumberland Plateau Level III ecoregion COLLABORATORS AND CONTRIBUTORS: John Jenkins (NRCS), Richard 23 25 48 Lake Agassiz Plain 79 29 19 Wasatch and Uinta Mountains 73 Mississippi Alluvial Plain Livingston (NRCS), James Keys (USFS); Phil Stewart (TDEC), Greg Russell 35 65 20 Colorado Plateaus 49 Northern Minnesota Wetlands Level IV ecoregion 32 74 74 Mississippi Valley Loess Plains 66f Limestone Valleys and Coves 68b Sequatchie Valley 24 33 21 Southern Rockies 50 Northern Lakes and Forests 75 Southern Coastal Plain (TDEC), Alan Woods (Dynamac Corporation), Joy Broach (TDEC), Linda 30 22 Arizona/New Mexico Plateau 51 North Central Hardwood 76 Southern Florida Coastal Plain 66g Southern Metasedimentary Mountains 68c Plateau Escarpment County boundary 32 Forests Cartwright (TDEC), Debbie Arnwine (Tennessee Department of Health), and 34 75 23 Arizona/New Mexico Mountains 77 North Cascades* 24 Southern Deserts 52 Driftless Area 78 Klamath Mountains* State boundary Thomas Loveland (USGS). 31 25 Western High Plains 53 Southeastern Wisconsin Till 79 Madrean Archipelago* 76 26 Southwestern Tablelands Plains
*Level III ecoregions identified in the ecoregion revision and subdivision process subsequent to the original map compilation (Omernik 1987).