EKU Faculty and Staff Scholarship

Significant Surface-Water Connectivity of Geographically Isolated Wetlands

Aram J. K. Calhoun, University of Maine
David M. Mushet Northern Prairie Wildlife Research Center, US Geological Survey
Laurie C. Alexander, US Environmental Protection Agency
Edward S. DeKeyser, North Dakota State University
Laurie Fowler, University of Georgia School of Law
Charles R. Lane, US Environmental Protection Agency
Megan W. Lang, National Wetland Inventory, US Fish and Wildlife Service
Mark C. Rains, University of South Florida
Stephen C. Richter, Eastern Kentucky University
Susan C. Walls, Wetland and Aquatic Research Center, US Geological Survey


We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be "geographically isolated" (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered to be "geographically isolated" shows the difficulties in grouping an ecological resource that does not reliably indicate lack of surface water connectivity in order to meet legal, regulatory, or scientific needs. Additionally, the practice of identifying "geographically isolated wetlands" based on distance from a stream can result in gross overestimates of the number of wetlands lacking ecologically important surface-water connections. Our findings do not support use of the overly simplistic label of "geographically isolated wetlands". Wetlands surrounded by uplands vary in function and surface water connections based on wetland landscape setting, context, climate, and geographic region and should be evaluated as such. We found that the "geographically isolated" grouping does not reflect our understanding of the hydrologic variability of these wetlands and hence does not benefit conservation of the Nation’s diverse wetland resources. Therefore, we strongly discourage use of categorizations that provide overly simplistic views of surface water connectivity of wetlands fully embedded in upland landscapes.