Biotic Communities of North America

David E. Brown, Peter J. Unmack & Thomas C. Brennan

We have recently published a series of short articles highlighting the existance of a digitized version of the biotic communities of North America (Brown et al. 2007) which has been slightly modified from the original published map (Brown et al. 1998; Reichenbacher et al. 1998).

Biotic communities are recognizable habitat assemblages that evolved within regional landscapes and are characterized by particular suites of plants and animals evolving within regional climatic patterns (Brown et al., 1998). As such, biotic communities are useful in describing habitat affinities of particular taxa of plants and animals and determining their biogeographical distribution (e.g., Brown 1982, 1994).

To facilitate the use of this GIS dataset we are making it available here in several formats compatable with ESRI GIS software.

There are two coverages available, one for the biotic communities, and one with the rivers and state boundaries that are already integrated to line up to lakes and other features in the biotic communities cover. Where a river and a political boundary overlaped we highlighted the river. Basic images of the two covers can be seen below.

Biotic Communities in arc/info export format and shapefile format.

Political Boundaries and Rivers in arc/info export format and shapefile format.

These are both projected as follows:

Datum NAD83
Major Axis 6370997.00000 Minor Axis 0.00000
radius of the sphere of reference 6370997.00000
longitude of center of projection -100 0 0.00
latitude of center of projection 45 0 0.000
false easting (meters) 0.00000
false northing (meters) 0.00000

Political Boundaries and Rivers


Biotic Communities


Brown, D.E., ed. 1982. The Biotic Communities of the American Southwest - United States and Mexico. Desert Plants, 4:1-341. Reprinted and revised 1994 as Biotic Communities: Southwestern United States and Northwestern Mexico. University of Utah Press, Salt Lake City, Utah. 342p.

Brown, D.E., Reichenbacher, F. and Franson, S.E. 1998. A Classification of North American Biotic Communities. University of Utah Press, Salt Lake City, Utah. 141p.

Brown, D.E., Unmack, P.J. & Brennan, T.C. 2007. Digitized map of biotic communities for plotting and comparing distributions of North American animals. The Southwestern Naturalist. 52: 610-616.

Reichenbacher, F., Franson, S.E. and Brown, D.E. 1998. The Biotic Communities of North America (scale 1:10,000,000). University of Utah Press, Salt Lake City, Utah.

If you have any questions please feel free to email Dave Brown at , Peter Unmack at or Tom Brennan at