Ecological Divisions

When looking at a map of the entire North American continent, conservationists find it useful to divide the land into manageable "units" that are ecologically discreet in terms of climate, animal life, and plant species distribution -- anything that contributes to and determines the biodiversity of a given area.

These units perform a second function, which is to help imperfect people speak a common language about the earth as we know it. When the scientific community, conservation groups, and concerned citizens meet to discuss planning and policy, it is very important that they understand which pieces of earth they are discussing -- and why. Ecological Divisions help each of these parties understand one another and keep the big picture in mind.

The following Ecological Division lines were created by modifying Ecoregions throughout the Western Hemisphere, which were established by The Nature Conservancy and World Wildlife Fund. North American examples include the Inter-Mountain Basins, the North American Warm Desert, the Western Great Plains, the Eastern Great Plains, the Laurentian and Acadian region, the Rocky Mountains, and the Atlantic and Gulf Coastal Plain.

As you can see, these are big areas of the continent. And yet, even at this broad level, there are interesting demarcations. For example, a "Rocky Mountain" ecoregion is predominantly found within the Rocky Mountain Ecological Division. But so is the "Southern Rocky Mountain" ecoregion, though it is limited to southern portions of the broader Rocky Mountain Ecological Division. The reason is clear: though each of these ecoregions are home to different plants and animals -- biota -- they share enough broad biogeographic history to be studied as one Ecological Division unit. Now, that's keeping the big picture in mind.

Ecological Divisions of the U.S.