![]() 2, 1964) as “vegetation that would exist today" if human influence ended and "the resulting plant succession" was "telescoped into a single moment”). These characteristics include geology, physiography, climate, soils, land use, wildlife, fish, hydrology, and vegetation (including “potential natural vegetation” defined by Küchler (p. The approach used to compile the ecoregion map 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). 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). Level IV ecoregions are further subdivisions of level III ecoregions. At level III, the continental United States contains 104 ecoregions and the conterminous United States has 84 ecoregions (U.S. Level II divides the continent into 52 regions (Commission for Environmental Cooperation Working Group, 1997). Level I is the coarsest level, dividing North America into 15 ecological regions. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. 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).Įcoregions 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). They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. Level III and IV Ecoregions of Arkansas-page size (852 kb)Įcoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. Level III and IV Ecoregions of Arkansas-page size (852 kb).Level III and IV Ecoregions of Arkansas-24" X 25" (832 kb).Level IV Ecoregions of Arkansas-poster back side 46" X 36" (568 kb).Level IV Ecoregions of Arkansas-poster front side 45" X 36" (3 mb).Instructions for applying symbology to ecoregions.Arkansas Level IV Metadata and Arkansas Level IV Symbology. ![]() Arkansas Level III Metadata and Arkansas Level III Symbology.Arkansas Arkansas GIS Data (shapefiles, metadata and symbology) To make sure you are using the most current ecoregion data, download shapefiles of ecoregions. ![]() If you do not find a link to a state that has been completed, maps and GIS data are available on the Ecoregion FTP site and web content will be available shortly. Some Web content for Level IV Ecoregions is under construction. Additionally, each state section contains links to downloadable maps in PDF format, and files containing GIS datasets (shapefiles, metadata, and symbology data). Select a state for descriptive information about that state's Level III and IV ecoregions.
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