This map is commonly called Bailey's ecoregions and shows ecosystems of regional extent in the United States, Puerto Rico, and the U.S. Virgin Islands, based on conditions in 1994. Four levels of detail are included to show a hierarchy of ecosystems. The largest ecosystems are domains, which are groups of related climates and which are differentiated based on precipitation and temperature. Divisions represent the climates within domains and are differentiated based on precipitation levels and patterns as well as temperature. Divisions are subdivided into provinces, which are differentiated based on vegetation or other natural land covers. The finest level of detail is described by subregions, called sections, which are subdivisions of provinces based on terrain features. Also identified are mountainous areas that exhibit different ecological zones based on elevation. Also included are maps of the Bailey Ecoregions of the United States in multiple formats and sizes.These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:7,500,000-scale data.Data were originally published on 02/23/2016. Minor metadata updates were made on 07/21/2016 and 12/19/2016. On 12/03/2019, the metadata was updated to include links to this National Geospatial Data Asset (NGDA) which was also available as a map service. Effective 03/12/2021, these data were no longer considered an NGDA so the link to the map service was removed on 03/22/2024 along with a few other minor metadata updates.

This multi-tiered, broad-scale, hierarchical system of ecoregions is based on numerous environmental variables at each level. The first two tiers are based on climate, followed by climate and physiograpghy, and finally topography and soils. This data was used to provide a general description of the ecosystem geography.

Bailey's Ecoregions of the World (1989)

This package consists of a geo-spatial data file, specifically, an ESRI polygon shape file, containing approximately 1700 polygons depicting the Bailey's Eco Regions classification system. (Consult http://www.nationalatlas.gov/mld/ecoregp.html for a summary of this system). Also included is an R-language script that applies a regularly-spaced point grid on top of the polygon map, and produces a geospatial point file containing samples of the Bailey's region code at each point in the grid.

Ths data set consists Bailey's Ecoregions polygons for the continental United States, sampled into raster grids at spatial resolutions of .1 and 1.0 degrees.

Global Ecoregions Map by Robert G. Bailey of the U.S. Fish and Wildlife Service. Provides a three level, heirarchical classification into Domains, Divisions and Provinces.

This layer contains polygon features of Ecological Units for the state of California as described by ECOMAP (1993) "... mapped based on associations of those biotic and environmental factors that directly affect or indirectly express energy, moisture, and nutrient gradients which regulate the structure and function of ecosystems. These factors include climate, physiography, water, soils, air, hydrology, and potential natural communities."

These divisions were first created by Bailey in 1976 and have been updated since. This dataset is the 2007 (Goudey) version.

This version of the ecoregion subsections was used by the California Department of Fish and Wildlife for their Areas of Conservation Emphasis work and their Wildlife Action Plan (https://wildlife.ca.gov/Data/Analysis/ACE & https://www.wildlife.ca.gov/SWAP/Final).

Complete metadata can be found here: https://www.fs.usda.gov/detail/r5/landmanagement/gis/?cid=fsbdev3_048133. The original data can be downloaded in full here: https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5351343.zip.

This dataset was uploaded to Data Basin and is available with additional information at: https://databasin.org/datasets/81a3a809a2ae4c099f2e495c0b2ecc91/

We assessed the geophysical settings within the larger context of natural ecoregions. Ecoregions are large contiguous units of land with similar environmental conditions (landforms, geology, and soils) which share a similar climate and a distinct assemblage of natural communities and species. The term “ecoregion" was coined by J.M. Crowley (1967) and later popularized by Robert Bailey of the US Forest Service (Bailey 1995). In recent decades, ecoregions have become a defining construct of larger conservation efforts because they provide an ecological context for understanding landscape-scale conservation activities by enabling the evaluation of properties considered critical to conserving biodiversity such as representation, complementarity, redundancy, ecological function, and endemism. The TNC ecoregions used for this analysis are modified from Bailey (1995) and were based on the subsections delineated by the U.S. Forest Service (USDA Forest Service ECOMAP Team 2007) and the Canadian Provinces (Ecological Stratification Working Group 1995). In comparison to Bailey’s ecoregions, TNC’s grouping of subsections puts more emphasis on physical characteristics and natural communities and less on climatic patterns.We made two changes to the ecoregions based on steering committee feedback.The boundary between the Tropical Florida and the Florida Peninsula ecoregions was not satisfactory with a number of science staff in Florida. The Peninsula Florida ecoregion extended southward along the Florida Gulf of Mexico and Atlantic Ocean coasts while Eastern Terrestrial Resilience Update 186 | Page it bowed northward at the interior of the Florida Peninsula. This ignored the temperature moderating effect of the Gulf and the ocean, making the climate warmer along the coast further to the north in Florida. The upward pointing bow, it was felt, should actually be a downward pointing bow. To model this desired new boundary between the two ecoregions, climate data was acquired from the Prism Climate Group of the Northwest Alliance for Computational Science and Engineering.TNC’s grouping of subsections puts more emphasis on physical characteristics and natural communities and less on climatic patterns. We made a revision to then ecoregions for this analysis which was to update the border between the Upper West Gulf Coastal Plain and the Mississippi River Alluvial Plain to the EPA Level III linework (US Environmental Protection Agency 2013) which more closely matched the landform patterns along that edge section.

Bailey's Ecoregions - Subregions by DivisionThis feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Forest Service (USFS), displays ecosystems by divisions in the United States, Puerto Rico and the U.S. Virgin Islands. Per the USFS, "Divisions represent the climates within domains and are differentiated based on precipitation levels and patterns as well as temperature".Mediterranean Division, Subtropical Division & Savanna DivisionData currency: This cached Esri federal service is checked weekly for updates from its enterprise federal source (Bailey's Ecoregions by Division) and will support mapping, analysis, data exports and OGC API – Feature access.Data.gov: Bailey's Ecoregions and Subregions DatasetGeoplatform: Bailey's Ecoregions and Subregions DatasetOGC API Features Link: (Baileys Ecoregions - Subregions by Division - OGC Features) copy this link to embed it in OGC Compliant viewersFor more information, please visit: Description of the Ecoregions of the United States For feedback please contact: Esri_US_Federal_Data@esri.comThumbnail image courtesy of: Bureau of Land ManagementNGDA Data SetThis data set is part of the NGDA Biodiversity Theme Community. Per the Federal Geospatial Data Committee (FGDC), Biodiversity is defined as pertaining to, or describing, "the dynamic processes, interactions, distributions, and relationships between and among organisms and their environments".For other NGDA Content: Esri Federal Datasets

This is the master spatial data layer for TNC's terrestrial ecoregions of the world, exported from the geodatabase listed above. Note that it includes Mangroves, Inland Water, and Rock and Ice MHTs, although they are not being handled by terrestrial assessments. This layer is based on WWF's ecoregions outside the United States, and loosely based on Bailey's ecoregions (from the USDA Forest Service) within the United States.Purpose: Developed originally by Olson, D. M. and E. Dinerstein (2002), Bailey (1995) and Environment Canada (Wiken, 1986), these data layers were modified by The Nature Conservancy (TNC) to be used in its Biodiversity Planning exercises in the process known as Ecoregional Assessments. Several Ecoregions were modified from the originals by TNC staff developing the aforementioned assessments. The modifications are based on ecological, bio-physical and political rationales; most changes are noted in the accompanying documentation (attributes). Ecoregions in Canada and Mexico were modified mainly at the border with US territory, where TNC modified-Bailey (1995) ecoregions crossed over the country boundaries and the Olson, D. M. and E. Dinerstein (2002) and (Wiken, 1986) were replaced where the TNC modified-Bailey (1995) overlayed them. This layer was split from the terrestrial ecoregional assessment layer in June 2008.

Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance (Bryce and others, 1999). These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and non-government organizations that are responsible for different types of resources within the same geographical areas (Omernik and others, 2000). The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity (Wiken, 1986; Omernik, 1987, 1995). These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels for ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions (Commission for Environmental Cooperation Working Group, 1997). At Level III, the continental United States contains 105 regions whereas the conterminous United States has 85 (U.S. Environmental Protection Agency, 2011). Level IV ecoregions are further subdivisions of Level III ecoregions. Methods used to define the ecoregions are explained in Omernik (1995, 2004), Omernik and others (2000), and Gallant and others (1989). This product is part of a collaborative effort primarily between USEPA Region VII, USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), Mississippi Department of Environmental Quality, Arkansas Department of Environmental Quality, Arkansas Multi-Agency Wetland Planning Team (MAWPT), U.S. Army Corps of Engineers (USACE), U.S. Department of Agriculture (USDA) - Natural Resources Conservation Service (NRCS), U.S. Department of Interior - Fish and Wildlife Service (USFWS), and U.S. Department of Interior - U.S. Geological Survey (USGS) - Earth Resources Observation Systems (EROS) Data Center. The project is associated with an interagency effort to develop a common framework of ecological regions. Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies that have been used to develop the most common ecoregion-type frameworks, including those developed by the U.S. Department of Agriculture - Forest Service (USFS) (Bailey and others, 1994), the USEPA (Omernik, 1987, 1995), and the NRCS (United States Department of Agriculture - Soil Conservation Service, 1981). As each of these frameworks is further refined, their differences are becoming less discernible. Regional collaborative projects such as this one in the Mississippi Alluvial Plain, where agreement can be reached among multiple resource management agencies, are a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation. Literature cited: Commission for Environmental Cooperation Working Group, 1997, Ecological regions of North America- toward a common perspective: Montreal, Commission for Environmental Cooperation, 71 p. Gallant, A. L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency, EPA/600/3-89/060, 152p. 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 Publishers, p.49-62. Omernik, J.M., Chapman, S.S., Lillie, R.A., and Dumke, R.T., 2000, Ecoregions of Wisconsin: Transactions of the Wisconsin Academy of Science, Arts, and Letters, v. 88, p. 77-103. Omernik, J.M., 2004, Perspectives on the nature and definitions of ecological regions: Environmental Management, v. 34, Supplement 1, p. s27-s38. U.S. Environmental Protection Agency. 2011. Level III and IV ecoregions of the continental United States. U.S. EPA, National Health and Environmental Effects Research Laboratory, Corvallis, Oregon, Map scale 1:3,000,000. Available online at: https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/eco-research/level-iii-and-iv-ecoregions-continental-united-states. Comments and questions regarding Ecoregions should be addressed to Glenn Griffith, USGS, c/o US EPA., 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4465, email:griffith.glenn@epa.gov Alternate: James Omernik, USGS, c/o US EPA, 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4458, email:omernik.james@epa.gov

This layer contains polygon features of Ecological Units for the state of California as described by ECOMAP (1993) "... mapped based on associations of those biotic and environmental factors that directly affect or indirectly express energy, moisture, and nutrient gradients which regulate the structure and function of ecosystems. These factors include climate, physiography, water, soils, air, hydrology, and potential natural communities." These divisions were first created by Bailey in 1976 and have been updated since. This dataset is the 2007 (Goudey) version. This version of the ecoregion subsections was used by the California Department of Fish and Wildlife for their Areas of Conservation Emphasis work and their Wildlife Action Plan (https://res1wildlifed-o-tcad-o-tgov.vcapture.xyz/Data/Analysis/ACE & https://res1wwwd-o-twildlifed-o-tcad-o-tgov.vcapture.xyz/SWAP/Final). Complete metadata can be found here: https://res1wwwd-o-tfsd-o-tusdad-o-tgov.vcapture.xyz/detail/r5/landmanagement/gis/?cid=fsbdev3_048133. The original data can be downloaded in full here: https://res1wwwd-o-tfsd-o-tusdad-o-tgov.vcapture.xyz/Internet/FSE_DOCUMENTS/stelprdb5351343.zip. This dataset was uploaded to Data Basin and is available with additional information at: https://res1databasind-o-torg.vcapture.xyz/datasets/81a3a809a2ae4c099f2e495c0b2ecc91/

This map layer is commonly called Baileys ecoregions and shows ecosystems of regional extent in the United States, Puerto Rico, and the U.S. Virgin Islands. Four levels of detail are included to show a hierarchy of ecosystems. The largest ecosystems are domains, which are groups of related climates and which are differentiated based on precipitation and temperature. Divisions represent the climates within domains and are differentiated based on precipitation levels and patterns as well as temperature. Divisions are subdivided into provinces, which are differentiated based on vegetation or other natural land covers. The finest level of detail is described by subregions, called sections, which are subdivisions of provinces based on terrain features. Also identified are mountainous areas that exhibit different ecological zones based on elevation.

Baileys Ecoregions - Subregions by DomainThis feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Forest Service (USFS), displays ecosystems by domains in the United States, Puerto Rico and the U.S. Virgin Islands. Per the USFS, "the largest ecosystems are domains, which are groups of related climates and which are differentiated based on precipitation and temperature".Humid Temperate Domain & Humid Tropical DomainData currency: This cached Esri federal service is checked weekly for updates from its enterprise federal source (Bailey's Ecoregions by Domain) and will support mapping, analysis, data exports and OGC API – Feature access.Data.gov: Bailey's Ecoregions and Subregions DatasetGeoplatform: Bailey's Ecoregions and Subregions DatasetOGC API Features Link: (Baileys Ecoregions - Subregions by Domain - OGC Features) copy this link to embed it in OGC Compliant viewersFor more information, please visit: Description of the Ecoregions of the United States For feedback please contact: Esri_US_Federal_Data@esri.comThumbnail image courtesy of: Bureau of Land ManagementNGDA Data SetThis data set is part of the NGDA Biodiversity Theme Community. Per the Federal Geospatial Data Committee (FGDC), Biodiversity is defined as pertaining to, or describing, "the dynamic processes, interactions, distributions, and relationships between and among organisms and their environments".For other NGDA Content: Esri Federal Datasets

Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance (Bryce and others, 1999). These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and non-government organizations that are responsible for different types of resources within the same geographical areas (Omernik and others, 2000). The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity (Wiken, 1986; Omernik, 1987, 1995). These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels for ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions (Commission for Environmental Cooperation Working Group, 1997). At Level III, the continental United States contains 105 regions whereas the conterminous United States has 85 (U.S. Environmental Protection Agency, 2011). Level IV ecoregions are further subdivisions of Level III ecoregions. Methods used to define the ecoregions are explained in Omernik (1995, 2004), Omernik and others (2000), and Gallant and others (1989). This product is part of a collaborative effort primarily between USEPA Region VII, USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), Mississippi Department of Environmental Quality, Arkansas Department of Environmental Quality, Arkansas Multi-Agency Wetland Planning Team (MAWPT), U.S. Army Corps of Engineers (USACE), U.S. Department of Agriculture (USDA) - Natural Resources Conservation Service (NRCS), U.S. Department of Interior - Fish and Wildlife Service (USFWS), and U.S. Department of Interior - U.S. Geological Survey (USGS) - Earth Resources Observation Systems (EROS) Data Center. The project is associated with an interagency effort to develop a common framework of ecological regions. Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies that have been used to develop the most common ecoregion-type frameworks, including those developed by the U.S. Department of Agriculture - Forest Service (USFS) (Bailey and others, 1994), the USEPA (Omernik, 1987, 1995), and the NRCS (United States Department of Agriculture - Soil Conservation Service, 1981). As each of these frameworks is further refined, their differences are becoming less discernible. Regional collaborative projects such as this one in the Mississippi Alluvial Plain, where agreement can be reached among multiple resource management agencies, are a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation. Literature cited: Commission for Environmental Cooperation Working Group, 1997, Ecological regions of North America- toward a common perspective: Montreal, Commission for Environmental Cooperation, 71 p. Gallant, A. L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency, EPA/600/3-89/060, 152p. 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 Publishers, p.49-62. Omernik, J.M., Chapman, S.S., Lillie, R.A., and Dumke, R.T., 2000, Ecoregions of Wisconsin: Transactions of the Wisconsin Academy of Science, Arts, and Letters, v. 88, p. 77-103. Omernik, J.M., 2004, Perspectives on the nature and definitions of ecological regions: Environmental Management, v. 34, Supplement 1, p. s27-s38. U.S. Environmental Protection Agency. 2011. Level III and IV ecoregions of the continental United States. U.S. EPA, National Health and Environmental Effects Research Laboratory, Corvallis, Oregon, Map scale 1:3,000,000. Available online at: https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/eco-research/level-iii-and-iv-ecoregions-continental-united-states. Comments and questions regarding Ecoregions should be addressed to Glenn Griffith, USGS, c/o US EPA., 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4465, email:griffith.glenn@epa.gov Alternate: James Omernik, USGS, c/o US EPA, 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4458, email:omernik.james@epa.gov

The purpose of the work, which began in 1976, was to show how the national forests of the United States fit within the global ecoregional scheme. In this system an ecoregion is defined as any large portion of the Earth's surface over which the ecosystems have characteristics in common. There are three levels in this classification system, the Domains, the Divisions and the Provinces.Ecoregions of the continents are based on macroclimate (i.e., the climate that lies just beyond the local modifying irregularities of landform and vegetation). The theory behind the approach is that macroclimates are among the most significant factors affecting the distribution of life on Earth. As the macroclimate changes, the other components of the ecosystem change in response. Macroclimates influence soil formation and help shape surface topography, as well as affecting the suitability for human habitation.Four Domains were defined: Polar, Humid temperate, Humid tropical and Dry. The combination of temperature and rainfall to indicate major climatic zones was based on Köppen and Trewartha's work, where dry climates were treated as a separate entity from Tropical humid and Temperate humid. However, the Köppen system defines an addtional "Subtropical" division at this level.The next level in the Bailey system is the Divisions, and these are also climate - based, for example in the Humid temperate Domain there is Hot continental, Warm continental, Subtropical, Marine, Prairie and Mediterranean, all with Mountain variants (i.e., a total of 12 Divisions in this Domain). There are a total of 30 of these.The third and last level are the Provinces, which are based on physiognomy of vegetation, modified by climate. For example, the Forest-Meadow of Eastern Oceanic (Monsoon climate). There are a total of 98 of these subdivisions.The global map has been digitised and converted to a geographic (lat/long) projection by the WCMC, Cambridge, UK. It is also available on CD from NOAAs National Geophysical Data Center in Boulder, Colorado as part of their Global Ecosystem Database Project. http://www.ngdc.noaa.gov/Store/.

This polygon shapefile depicts global ecoregions, major habitat types, biogeographical realms and The Nature Conservancy terrestrial assessment units as of December 14, 2009. Developed originally by Olson, D. M. and E. Dinerstein (2002), Bailey (1995) and Environment Canada (Wiken, 1986), these data layers were modified by The Nature Conservancy (TNC) to be used in its Biodiversity Planning exercises in the process known as Ecoregional Assessments. Several Ecoregions were modified from the originals by TNC staff developing the aforementioned assessments. The modifications are based on ecological, bio-physical and political rationales; most changes are noted in the accompanying documentation (attributes). Ecoregions in Canada and Mexico were modified mainly at the border with US territory, where TNC modified-Bailey (1995) ecoregions crossed over the country boundaries and the Olson, D. M. and E. Dinerstein (2002) and (Wiken, 1986) were replaced where the TNC modified-Bailey (1995) overlayed them. This layer was split from the terrestrial ecoregional assessment layer in June 2008.

This is a shapefile showing the ecoregions of the state of Nebraska as defined in conjunction with the development of a comprehensive wildlife conservation plan (Schneider et al 2005, aka the Natural Legacy Plan) for the state. The following description of the ecoregion layer and the sources of data used to create it were copied directly from Appendix 10 (page 246) of that document: Ecoregions are relatively large units of land and water delineated by the biotic and abiotic factors (e.g. climate, topography, geology, vegetation) that regulate the structure and function of the ecosystems within them. There are two main ecoregion maps for the United States, one developed by the U.S. Forest Service (Bailey et al. 1994) and the other developed by the U.S. Environmental Protection Agency (Omernik et al. 1987). For the Natural Legacy Project we delineated ecoregions using primarily Level III ecoregion lines from Ecoregions of Nebraska and Kansas (Chapman et al. 2001), which was a joint project of the USFS and EPA to blend the two systems. However, we used Bailey's Section level line to delineate the western boundary of tallgrass prairie south of the Sandhills since this was a better fit with Kaul and Rolfsmeier's (1993) map of the native vegetation of Nebraska.

Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of patterns of biotic and abiotic phenomena, including geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another. A Roman numeral hierarchical scheme has been adopted for different levels for ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions (Commission for Environmental Cooperation Working Group, 1997). At Level III, the continental United States contains 104 regions whereas the conterminous United States has 85 (U.S. Environmental Protection Agency, 2005). Level IV ecoregions are further subdivisions of Level III ecoregions. Methods used to define the ecoregions are explained in Omernik (1995, 2004), Omernik and others (2000), and Gallant and others (1989). Data Download: https://app.fw.ky.gov/kfwis/kygeonet/ecoregion2012.zip Literature cited: Bailey, R.G., Avers, P.E., King, T., and McNab, W.H., eds., 1994, Ecoregions and subregions of the United States (map): Washington, D.C., USFS, scale 1:7,500,000.Bryce, S.A., Omernik, J.M., and Larsen, D.P., 1999, Ecoregions—a geographic framework to guide risk characterization and ecosystem management: Environmental Practice, v. 1, no. 3, p. 141-155.Commission for Environmental Cooperation Working Group, 1997, Ecological regions of North America- toward a common perspective: Montreal, Commission for Environmental Cooperation, 71 p. Gallant, A. L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency, EPA/600/3-89/060, 152p. Griffith, G., Omernik, J., Azevedo, S., 1998, Ecoregions of Tennessee (text, map, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey, map scale 1:940,000.McMahon, G., Gregonis, S.M., Waltman, S.W., Omernik, J.M., Thorson, T.D., Freeouf, J.A., Rorick, A.H., and Keys, J.E., 2001, Developing a spatial framework of common ecological regions for the conterminous United States: Environmental Management, v. 28, no. 3, p. 293-316.Omernik, J.M., 1987, Ecoregions of the conterminous United States (map supplement): Annals of the Association of American Geographers, v. 77, p. 118-125, scale 1:7,500,000.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 Publishers, p.49-62. Omernik, J.M., Chapman, S.S., Lillie, R.A., and Dumke, R.T., 2000, Ecoregions of Wisconsin: Transactions of the Wisconsin Academy of Science, Arts, and Letters, v. 88, p. 77-103.Omernik, J.M., 2004, Perspectives on the nature and definitions of ecological regions: Environmental Management, v. 34, Supplement 1, p. s27-s38.U.S. Department of Agriculture–Soil Conservation Service, 198, Land resource regions and major land resource areas of the United States: Agriculture Handbook 296, 156 p.U.S. Environmental Protection Agency, 2002, Level III ecoregions of the continental United States (revision of Omernik, 1987): Corvallis, Oregon, USEPA–National Health and Environmental Effects Research Laboratory, Map M-1, various scales.Wiken, E., 1986, Terrestrial ecozones of Canada: Ottawa, Environment Canada, Ecological Land Classification Series no. 19, 26 p.Woods, A.J., Omernik, J.M., Brockman, C.S., Gerber, T.D., Hosteter, W.D., and Azevedo, S.H., 1998, Ecoregions of Indiana and Ohio: Reston, USGS, map scale 1:500,000Comments and questions regarding the Level III and IV Ecoregions should be addressed to Glenn Griffith, USGS, c/o US EPA., 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4465, email:griffith.glenn@epa.gov Alternate: James Omernik, USGS, c/o US EPA, 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4458, email:omernik.james@epa.govThis was first downloaded by KDFWR in 2005 for the State Wildlife Action Plan and then updated in 2012 again to reflect an updated national shapefile. Kentucky Department of Fish and Wildlife Resources downloaded first the Kentucky Data set https://www.epa.gov/eco-research/ecoregion-download-files-state-region-4#pane-15 , but saw that the boundary did match well the Kentucky state boundary maintained by KY Geonet. We then downloaded the national data set obtained from https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-continental-united-statesand intersected to the KY DGI state boundary, For those slivers assigned to unexpected ecoregions (55d Pre-Wisconsinan Drift Plains, 67h Southern Sandstone Ridges, 71m Northern Shawnee Hills, 71n Southern Shawnee Hills, 73c St. Francis Lowlands) we merged to the geographically nearest polygon so that the ecoregions found in this dataset match that in the poster Ecoregions of Kentucky.

description: Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance (Bryce, Omernik, and Larsen, 1999). Ecoregions are general purpose regions that are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources in the same geographical areas (Omernik and others, 2000). A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 52 regions (Commission for Environmental Cooperation Working Group, 1997). At level III, the continental United States contains 104 ecoregions and the conterminous United States has 84 ecoregions (U.S. Environmental Protection Agency [USEPA], 2003). Level IV ecoregions are further subdivisions of level III ecoregions. Methods used to define the USEPA's ecoregions are explained in Omernik (1995), Omernik and others (2000), and Gallant and others (1989). The approach used to compile the ecoregions of Arkansas is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic characteristics that affect or reflect differences in ecosystem quality and integrity (Wiken, 1986; Omernik, 1987, 1995). These characteristics include geology, physiography, climate, soils, land use, wildlife, fish, hydrology, and vegetation (including "potential natural vegetation" defined by Kchler (p. 2, 1964) as "vegetation that would exist today" if human influence ended and "the resulting plant succession" was "telescoped into a single moment"). The relative importance of each characteristic varies from one ecological region to another regardless of ecoregion hierarchical level. In Arkansas, there are 7 level III ecoregions and 32 level IV ecoregions; all but four of these level IV ecoregions are also found in ecologically similar parts of adjacent states (Chapman and others, 2002, 2004a, 2004b; Griffith, Omernik, and Azevedo, 1998). Arkansas' ecological diversity is strongly related to regional physiography, geology, soil, climate, and land use. Elevated karst plateaus, folded mountains, agricultural valleys, forested uplands, and bottomland forests occur. Fire-maintained prairie was once extensive in several parts of the state. The ecoregion were compiled at a scale of 1:250,000, and depict revisions and subdivisions of earlier level III ecoregions that were originally compiled at a smaller scale (U.S. Environmental Protection Agency, 2003; Omernik, 1987). It is part of a collaborative project primarily between USEPA Region 6, USEPA-National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), and the Multi-Agency Wetland Planning Team (MAWPT), which comprises representatives of six Arkansas state agencies (Arkansas Natural Heritage Commission, Arkansas Soil and Water Conservation Commission, Arkansas Game and Fish Commission, Arkansas Department of Environmental Quality, Arkansas Forestry Commission, and University of Arkansas Cooperative Extension Service). Collaboration and consultation also occurred with the U.S. Army Corps of Engineers (USACE), U.S. Department of Agriculture-Natural Resources Conservation Service (NRCS), U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service, USGS-Earth Resources Observation Systems Data Center, and University of Arkansas-Center for Advanced Spatial Technologies. This project is associated with an interagency effort to develop a common framework of ecological regions (McMahon and others, 2001). Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies applied to develop the most common ecoregion-type frameworks, including those developed by the U.S. Department of Agriculture-Forest Service (Bailey and others, 1994), the USEPA (Omernik 1987, 1995), and the U.S. Department of Agriculture-Soil Conservation Service (1981). As each of these frameworks is further refined, their differences are becoming less discernible. Each collaborative ecoregion project, such as this one in Arkansas, is a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation. Comments and questions regarding the Level III and IV Ecoregions of Arkansas should be addressed to Alan Woods, Oregon State University, c/o US EPA., 200 SW 35th Street, Corvallis, OR 97333, (541) 754-4469, email: woods.alan@epa.gov, or to James Omernik, USGS, c/o US EPA, 200 SW 35th Street, Corvallis, OR 97333, (541) 754-4458, email: omernik.james@epa.gov; abstract: Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance (Bryce, Omernik, and Larsen, 1999). Ecoregions are general purpose regions that are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources in the same geographical areas (Omernik and others, 2000). A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 52 regions (Commission for Environmental Cooperation Working Group, 1997). At level III, the continental United States contains 104 ecoregions and the conterminous United States has 84 ecoregions (U.S. Environmental Protection Agency [USEPA], 2003). Level IV ecoregions are further subdivisions of level III ecoregions. Methods used to define the USEPA's ecoregions are explained in Omernik (1995), Omernik and others (2000), and Gallant and others (1989). The approach used to compile the ecoregions of Arkansas is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic characteristics that affect or reflect differences in ecosystem quality and integrity (Wiken, 1986; Omernik, 1987, 1995). These characteristics include geology, physiography, climate, soils, land use, wildlife, fish, hydrology, and vegetation (including "potential natural vegetation" defined by Kchler (p. 2, 1964) as "vegetation that would exist today" if human influence ended and "the resulting plant succession" was "telescoped into a single moment"). The relative importance of each characteristic varies from one ecological region to another regardless of ecoregion hierarchical level. In Arkansas, there are 7 level III ecoregions and 32 level IV ecoregions; all but four of these level IV ecoregions are also found in ecologically similar parts of adjacent states (Chapman and others, 2002, 2004a, 2004b; Griffith, Omernik, and Azevedo, 1998). Arkansas' ecological diversity is strongly related to regional physiography, geology, soil, climate, and land use. Elevated karst plateaus, folded mountains, agricultural valleys, forested uplands, and bottomland forests occur. Fire-maintained prairie was once extensive in several parts of the state. The ecoregion were compiled at a scale of 1:250,000, and depict revisions and subdivisions of earlier level III ecoregions that were originally compiled at a smaller scale (U.S. Environmental Protection Agency, 2003; Omernik, 1987). It is part of a collaborative project primarily between USEPA Region 6, USEPA-National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), and the Multi-Agency Wetland Planning Team (MAWPT), which comprises representatives of six Arkansas state agencies (Arkansas Natural Heritage Commission, Arkansas Soil and Water Conservation Commission, Arkansas Game and Fish Commission, Arkansas Department of Environmental Quality, Arkansas Forestry Commission, and University of Arkansas Cooperative Extension Service). Collaboration and consultation also occurred with the U.S. Army Corps of Engineers (USACE), U.S. Department of Agriculture-Natural Resources Conservation Service (NRCS), U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service, USGS-Earth Resources Observation Systems Data Center, and University of Arkansas-Center for Advanced Spatial Technologies. This project is associated with an interagency effort to develop a common framework of ecological regions (McMahon and others, 2001). Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies applied to develop the most common ecoregion-type frameworks, including those developed by the U.S. Department of Agriculture-Forest Service (Bailey and others, 1994), the USEPA (Omernik 1987, 1995), and the U.S. Department of Agriculture-Soil Conservation Service (1981). As each of these frameworks is further refined, their differences are becoming less discernible. Each collaborative ecoregion project, such as this one in Arkansas, is a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation. Comments and questions regarding the Level III and IV Ecoregions of Arkansas should be addressed to Alan Woods, Oregon State University, c/o US EPA., 200