Simmons, B. A.; Beck, M. W.; Flaherty-Walia, K.; Lewis, J.; Sherwood, E. T.

For decades, federal protections were extended to wetlands adjacent to navigable \"waters of the US\" by the Clean Water Act. In its Sackett v. EPA ruling, however, the US Supreme Court redefined the meaning of \"adjacent,\" eliminating protections to wetlands without a continuous surface connection to these waters (i.e., geographically isolated wetlands). Yet it remains unclear how this continuous surface test will work in reality, where ecological connectivity often extends beyond physical connectivity. Here, we estimate that 22-36% of US wetlands could be considered geographically isolated, depending upon how isolation is defined on the ground, with wetlands in the Midwest and Northeast at greatest risk of losing protection. Stable state-level protections are urgently needed to secure the country\'s wetlands from further pollution and destruction.