Nearctic terrestrial ecoregions See also List of ecoregions in Canada (WWF) List of ecoregions in Mexico (WWF) List of ecoregions in the United States (WWF) References Abell, R.A. et al. (2000). Freshwater Ecoregions of North America: A Conservation Assessment Washington, DC: Island Press, Freshwater Ecoregions of North America: A Conservation Assessment. Flannery, Tim (2001). The Eternal Frontier: an Ecological History of North America and its Peoples. Grove Press, New York. Ricketts, Taylor H., Eric Dinerstein, David M. Olson, Colby J. Loucks, et al. (1999). Terrestrial Ecoregions of North America: a Conservation Assessment. Island Press, Washington DC., Terrestrial Ecoregions of North America: A Conservation Assessment. External links Map of the ecozones Nearctica, The Natural World of North America Biogeographic realms