You searched for: Subject Biotic communities Remove constraint Subject: Biotic communities Place Massachusetts Remove constraint Place: Massachusetts Place United States Remove constraint Place: United States Data type Polygon Remove constraint Data type: Polygon Format Shapefile Remove constraint Format: Shapefile
2004. United States. Forest Service. This polygon shapefile is commonly called Bailey's ecoregions and shows ecosystems of regional extent in the United States, Puerto Rico, and the U.... National Atlas of the United States.
2003. United States. Environmental Protection Agency. This polygon shapefile shows Omernik's Level III ecoregions, derived from a 1:7,500,000 map created by J.M. Omernik in 1987 and from refinements of... National Atlas of the United States.