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Biodiversity Values of Geographically Isolated Wetlands in the United States

As a result of a 2001 Supreme Court decision (Solid Waste Agency of Northern Cook County vs. U.S. Army Corps of Engineers, 2001), some wetlands and other waters that are considered "geographically isolated" from navigable waters may no longer fall under the jurisdiction of the Clean Water Act, and therefore may no longer be under federal protection from development. The objective of this study was to assess the impacts on biodiversity of the Supreme Court’s decision.


This study documents that isolated wetland ecological systems support high levels of biodiversity, including significant numbers of at-risk species and plant communities.

Unless there is a policy response that reframes the jurisdiction of isolated wetlands under the Clean Water Act, States, tribes and local governments will increasingly be in a position to decide the fate of those isolated wetlands that no longer are protected under the Clean Water Act. The information and analyses contained in this study are designed to assist policy-makers and land managers at federal, state, and local levels to better understand their biodiversity value and plan for their conservation.