natureserve.org contains tons of polygon and point data displaying the distribution areas for mammals, birds and other eco data. Plant distribution may be available at a later date
Birds of North America
Mammals of North America
a2a_linkname=”Bird and Mammal Distribution Areas”;
a2a_linkurl=”http://geoserf.com/?p=6″;
The following link contains shapefiles for download containing native range/distribution areas for various North American trees and plants.
“Maps of the ranges of tree species in North America compiled by Elbert Little, of the U.S. Department of Agriculture, Forest Service, and others (see references below) were digitized for use in USGS’ vegetation-climate modeling studies. These digital [...]