*EcoRegions of the United States, Nearctic ecozone
Collections Sites for
Nematode Community Surveys and Criconematid Nematodes
Location of (both) nematode Community Surveys in the U.S. and Criconematid specimen collections
Ecoregions from which Criconematid nematodes have been collected
(also Community surveys at

*Ecoregions map after "Terrestrial Ecoregions of North America: A Conservation Assessment." 
Ricketts, T.H., E. Dinerstein, D.M. Olson, C.J. Loucks, et al.  (1999) World Wildlife Fund - United States and Canada.  Island Press, Washington, D.C.
as appearing on Bioimages website- http://www.cas.vanderbilt.edu/bioimages/frame.htm