Ecological Classification Systems

This map shows subzones, regions, and subregions of aquatic zoogeography in North America (Nearctic Zone) and represents a synthesis of information derived from published literature and consultation with selected ichthyologists. The units are based on distributions of native fish species and follow hydrographic boundaries. Similarity indices that reflect the entire composition of fish species assemblages were used to define these units. Subzones have species similarity indices of less than 20%. Regions and subregions have similarity indices of less than 45% and 70%, respectively. Subregions have not yet been defined for the Mexican Transition subzone. More detailed hierarchical levels of aquatic zoogeography (river basins, subbasins, watersheds, subwatersheds) are described in Maxwell, J.R., C.J. Edwards, M.E. Jensen, S.J. Paustian, H. Parrott and D.M. Hill. 1995. A hierarchical framework of aquatic ecological units in North America. Gen. Tech. Rep. NC-176. St. Paul, MN: U.S. Forest Service, North Central Forest Experiment Station. 72 p.

The following higher resolution version of the above map may be downloaded by clicking the link below.

For more information, contact

Tina Baumann
USDA-Forest Service
North Central Research Station
5985 Hwy K, Rhinelander WI 54529

Phone: 715-365-1101
contact

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