LEVEL III AND IV 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 and others, 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). 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 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 (United States Environmental Protection Agency [USEPA] 2000). Level IV is a further subdivision of level III ecoregions. Explanations of the methods used to define the USEPA's ecoregions are given in Omernik (1995), Omernik and others (2000), and Gallant and others (1989). In Kentucky, there are 7 level III ecoregions and 25 level IV ecoregions; all but four continue into ecologically similar parts of adjacent states. Ecological and biological diversity in Kentucky is enormous and is strongly related to regional physiographic, geologic, land use, soil, and watershed characteristics. Kentucky contains forested and dissected ridges, open hills, knobs, and escarpments as well as agriculturally-dominated rolling plains, karst plains, and flood plains. In addition, two major coal fields, one in the west and one in the east, occur. The level III and IV ecoregion map on this poster was compiled at a scale of 1:250,000 and depicts revisions and subdivisions of earlier level III ecoregions that were originally compiled at a smaller scale (USEPA 2000; Omernik 1987). This poster is part of a collaborative project primarily between USEPA Region IV, USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), Kentucky Department of Environment Protection (KDEP). Collaboration and consultation also occurred with the United States Department of Agriculture?Forest Service (USFS), United States Department of the Interior?Geological Survey (USGS)?Earth Resources Observation Systems (EROS) Data Center, Kentucky Geological Survey (KGS), The Nature Conservancy (TNC), United States Department of Agriculture?Natural Resources Conservation Service (NRCS), and with other State of Kentucky agencies. The 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 USFS (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 Kentucky, comprises a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation.