Take a look at the map of the United States. The country can be divided up in two ways—one by state, and one by ecoregion. Whereas state boundaries were created by people, the ecoregion boundaries on this map were created by Mother Nature.

map of terrestrial eco-regions of North America

Ecoregions are areas that have similar climate, geology, and soils. These abiotic (non-biological) factors determine what plants and animals can live in the ecosystem. Even though two places might be far apart, if they are part of the same ecoregion, we can predict they will have similar species.

For example, a mixed deciduous-coniferous forest in Maine will have similar plants and animals to a mixed deciduous-coniferous forest in Minnesota. By using an ecoregion map, we can gain a lot of clues into the ecology of different places in the United States and the world.

At the broadest scale, the United States is divided according to patterns of climate. At the province level, ecoregions are divided according to vegetation and other natural land cover. To understand each specific ecoregion of the United States, visit the U.S. Forest Service.

By studying ecoregions, we begin to understand more about the history, ecology, and biodiversity of the United States. Conservationists use ecoregions to help in habitat protection and restoration projects and to produce recovery plans for endangered species. Historians and biologists study ecoregions to map out the connection between the settlements of early indigenous peoples and wildlife and how the ecology has changed over time.

Get Involved

Where We Work

More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

Learn More
Regional Centers and Affiliates