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Home › Map Layers › Bailey's Ecoregions and Subregions of the United States, Puerto Rico, and the U.S. Virgin Islands



## Map Layer Info

Bailey's Ecoregions and Subregions of the United States, Puerto Rico, and the U.S. Virgin Islands

What this map layer shows:

Ecoregions defined by common climatic and vegetation characteristics, shown as domains, divisions, provinces and sections.

Background Information

Ecoregions are ecosystems of regional extent. Bailey's ecoregions distinguish areas that share common climatic and vegetation characteristics. A four-level hierarchy

is used to differentiate the ecoregions, with the broadest classification being the domain.

Domains are groups of related

climates and are differentiated based on precipitation and temperature.

There are four domains used for worldwide ecoregion classification and all four appear in the United States: the polar domain, the humid temp erate domain, the dry domain, and the humid tropical domain. Divisions represent the climates within domains and are differentiated based on precipitation leve ls and patterns as well as temperature.

Divisions are subdivided into provinces , which are differentiated based on vegetation or other natural land covers. Mountainous areas that exhibit different ecological zones based on elevation are iden tified at the province level. The finest level of detail is described by subregions, called sections , which are subdivisions of provinces based on terrain features.

The purpose of ecological land classificati on is to provide information for both the development of resources and the conserva tion of the environment. Government and private land managers use this inform ation to estimate ec osystem productivity, to determine probable responses to land management practices, and to address environmental issues over large areas, such as air pollution, forest disease, or threats to biodiversity. This map layer was compiled by the USDA Forest Service

.

The Bailey's Ecoregions and Subregions of the United States, Puerto Rico, and the U.S. Virgin Islands map layer shows the ec oregion domains, divisions, provinces,

and sections for this area. Further informat ion on domains, divisions, and provinces

is available from the USDA Forest Service Rocky Mountain Research Station page describing Ecoregions of the United States , and detailed information on sections is available through the USDA Forest Service page, Ecological Subregio ns of the United

States

.

The National Atlas also includes a map layer showing Omernik's Level III Ecoregions , which are defined by a wide variety of characteristics, including BIOLOGY

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## Pa g e 1 of 2 Baile y 's Ecore g ions and Subre g ions of the United States, Puerto Rico, and the U.S. Vir g in

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6/12/2011 htt p ://www.nationalatlas. g ov/mld/ecore gp .htmlvegetation, animal life, geology, soils, water, climate, and human land use, as well as other living and non-living ecosystem components.

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Last modified: Thursday, 27-Jan-2011 17:11:30 CST 

## Pa g e 2 of 2 Baile y 's Ecore g ions and Subre g ions of the United States, Puerto Rico, and the U.S. Vir g in

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6/12/2011 htt p ://www.nationalatlas. g ov/mld/ecore gp .html