Level III Ecoregions of Maryland
type: Dataset
description: Ecoregions by state 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. 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 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). 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…
issued: 2025-11-22T19:58:18.419059
modified: 2025-11-22T19:58:18.419064
spatial: Location
keyword: amerigeo
keyword: amerigeoss
keyword: ckan
keyword: ecosystem
keyword: environment
keyword: geo
keyword: geoss
keyword: management
keyword: national
keyword: natural-resources
keyword: north-america
keyword: surface-water
keyword: united-states

Web Resource
type: Distribution
issued: 2021-06-04T22:12:05.077254
modified: 2025-11-22T19:58:18.410706
access URL: https://edg.epa.gov/metadata/

Zip File
type: Distribution
description: md_eco_l3.zip
format: ZIP
issued: 2021-06-04T22:12:05.077246
modified: 2025-11-22T19:58:18.410255
access URL: https://gaftp.epa.gov/EPADataCommons/ORD/Ecoregions/md/md_eco_l3.zip

US Migrating
type: Agent