The National Wetland Plant List (NWPL) is an essential tool for determining hydrophytic vegetation in wetlands under federal regulations, including the Clean Water Act and the Rivers and Harbors Act. Managed by the U.S. Army Corps of Engineers (USACE) in collaboration with the EPA, FWS, and NRCS, the NWPL is periodically updated to reflect new species records, taxonomic changes, and range extensions. For 2024, proposed changes to the wetland indicator status ratings of ten plant species across five regions are open for public comment until March 31, 2025. These ratings help classify plants into five categories—Obligate Wetland (OBL), Facultative Wetland (FACW), Facultative (FAC), Facultative Upland (FACU), and Upland (UPL)—based on their likelihood of occurring in wetlands. The NWPL serves as a critical resource for wetland restoration, conservation, and regulatory compliance.
The 2024 NWPL update process involved reviews by both Regional Panels (RPs) and the National Panel (NP) to assess proposed changes. One public request to change the status of Cicendia quadrangularis in the Arid West region was found to be unnecessary as the requested designation was already in place. However, changes were considered for two other species, Alnus incana and Amaranthus tuberculatus. Additionally, the Alaska RP requested evaluations for eight species with varying wetland indicator status ratings across subregions. Using advanced analytical methods such as multiple correspondence analysis and machine learning, the U.S. Army Engineer Research and Development Center collaborated with the Alaska RP to refine these ratings. The research findings informed proposed changes for several species while others remained unchanged due to insufficient data.
For specific species, revisions included downgrading Andromeda polifolia from OBL to FACW in certain subregions and adjusting Arctous rubra to match the state’s FAC designation. Salix arctica and Salix pulchra underwent reclassifications in specific subregions, while Viola palustris was proposed for a shift from FAC to FACW in select Major Land Resource Areas. The USACE encourages public participation in the NWPL update process by submitting data, observations, and supporting literature. Expert insights from regional botanists, field studies, and historical records help ensure accurate and scientifically supported classifications. Public input will be compiled and reviewed by the NP before finalizing the 2024 NWPL updates.