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Riverscour Ecosystems of Eastern Unglaciated North America: A Review
Natural Areas Journal

In a newly published study with contributors from Southeastern Grasslands Institute, Austin Peay State University, NatureServe, Pennsylvania Natural Heritage Program (PNHP), West Virginia Division of Natural Resources, and Texas Parks and Wildlife, scientists defined riverscour as unique and diverse habitats found along rocky, stable river zones that resemble grasslands, wetlands, and floodplains. They are maintained by violent floods that blast down the rivers from time to time, carrying cobbles and boulders that scour away trees and tip the balance in favor of shrubs and grassland plants.  

Authors of the paper identified 1,322 river segments that contain riverscour in Eastern Unglaciated North America. Although these habitats are relatively small, they are home to a significant number of rare and endemic species. For example, in Tennessee alone, riverscour occupies less than 1% of the region but supports 25% of the area's state- and federally-listed plant species! Unfortunately, riverscour faces various threats, including flooding from river impoundment, invasive species, recreational activities, and climate change. Protecting and managing these ecosystems is crucial for preserving the unique biodiversity of eastern North America. 

Estes, D., C. Tracey, E. Zimmerman, W.Knapp, J. Vanderhorst, J. Singhurst, and T. Witsell. Riverscour Ecosystems of Eastern Unglaciated North America: A Review. Natural Areas Journal, 43(3), 148-168, (2023).