This web site represents a national effort led by the U.S. Army Corps of Engineers (USACE) to update and maintain the National Wetland Plant List (NWPL). The NWPL contains wetland indicator status ratings for individual plant species, which are used in determining whether the hydrophytic vegetation factor is met when conducting wetland delineations under the Clean Water Act and wetland determinations under the Wetland Conservation Provisions of the Food Security Act. Other applications of the NWPL include wetland research, the development of restoration and compensatory mitigation goals, and for providing general botanical information about wetland plants. The NWPL is an interagency effort which is led by USACE and supported by the U.S. Environmental Protection Agency (EPA), the U.S. Fish and Wildlife Service (USFWS), and the U.S. Department of Agriculture - Natural Resources Conservation Service (USDA-NRCS). The NWPL covers all 50 U.S. states, the District of Columbia, and the U.S. Caribbean and Pacific islands that are territories of the U.S. However, to provide additional insights regarding plant distribution awareness, we have included the total geographic range for each taxon throughout North America north of Mexico.
The NWPL previously existed as the “National List of Plant Species that Occur in Wetlands” and was administered by the USFWS, in coordination with the other three agencies, where periodic updates were executed through a series of regional meetings. In 2006, administration of the NWPL was transferred to the USACE, and the current interagency governance structure was established. The first major 2012 update of the NWPL was a cooperative effort between USACE, EPA, USFWS, and USDA-NRCS, along with input from the Biota of North America Program (BONAP), states, Indian Nations, the academic community, and the public. The wetland plant data on the NWPL are organized into ten regions that coincide with the USACE wetland delineation regions. Each region is represented by a panel consisting of a botanist or ecologist from each of the four lead federal agencies. These Regional Panels, in conjunction with the National Panel, established the draft wetland ratings, and the other participants and reviewers made comments to improve the list. Additionally, each region had an external professional panel of three botanists who reviewed specific taxa.
The NWPL web site has two components: one that is used for updating the NWPL and the other that is for public use. The NWPL website increases transparency of the NWPL update process and enables public participation in that process. The general NWPL update process is described in two USACE publications:
The nomenclature, distribution, and biological data presented here originally represented a collaborative effort between the participating federal agencies and BONAP. However, since 2017, a Memorandum of Agreement among the four federal agencies established USDA PLANTS as the NWPL’s formal authority for nomenclature. It is planned that the NWPL will also be updated to include the upland portion of the flora for use in the wetland programs that it supports. Phytogeographic distribution patterns in the NWPL are presented at the state, county, parish, or borough levels. Puerto Rico, the U.S. Virgin Islands, Hawai’i, the islands of Guam, the Northern Marianas, and U.S. Samoa are listed separately from the continental U.S. Puerto Rico and the U.S. Virgin Islands comprise the Caribbean Region and Hawaii, the islands of Guam, the Northern Marianas, and U.S. Samoa comprise Hawai’i and the Pacific Islands. The web site includes biological data associated with each taxon, as well as range maps and photographs. Maintaining and updating the NWPL supports USACE and its Federal partners in delivering a more predictable, transparent, and scientifically-based regulatory program.