The U.S. Army Corps of Engineers (Corps), Honolulu District, announces the availability of the updated National Wetland Plant List (NWPL). The NWPL plays a critical role in wetland determinations under the Clean Water Act and Food Security Act. Wetlands are evaluated using three parameters – soils, hydrology and vegetation. Using sampling protocols outlined in the Regional Supplements to the 1987 Wetland Delineation Manual, the indicator status is then used to determine whether the vegetation parameter is met.
The 2012 NWPL should be used in any wetland delineations performed after June 1, 2012. The 2012 NWPL may be used in delineations/determinations conducted prior to that date and, for the purpose of clarity and accurate interpretation, should be referenced in delineation reports or regional supplement determination forms.
The NWPL is a list of plants with their updated nomenclature and their assigned indicator statuses. An indicator status reflects the likelihood that a particular plant occurs in a wetland or upland. The five indicator status definitions are: OBL: Almost always is a hydrophyte, rarely in uplands; FACW: Usually is a hydrophyte but occasionally found in uplands; FAC: Commonly occurs as either a hydrophyte or non-hydrophyte; FACU: Occasionally is a hydrophyte but usually occurs in uplands; and UPL: Rarely is a hydrophyte, almost always in uplands.
The lead responsibility to update the 1988 list was transferred from the US Fish & Wildlife Service (FWS) to the Corps in December 2006. The 2012 NWPL is the culmination of a six year interagency process to update the 1988 National List of Plant Species That Occur in Wetlands (Reed 1988). This national effort also has involved the three other Federal agencies with legal responsibilities for wetlands: the U.S. Environmental Protection Agency (EPA), the FWS, and the Natural Resources Conservation Service (NRCS). This update represents the most complex and thorough evaluation of wetland plant species ratings since the inception of the 1988 list, and it allows for greater input across more professional institutions with increased public access to critical information.
The 2012 NWPL, background information including previous names and indicator statuses, public comments and responses to the comments received in response to the January 6, 2011 Federal Register notice, and the website citation may be found at:
Specific changes include:
- Providing the status ratings of over 8,200 plants
- A dedicated website that includes photos, previous status ratings and other botanical information
- Updated nomenclature for over 2400 plants
- Ecoregions matching those of the Regional Supplements to the 1987 Wetland Delineation Manual
- Descriptions of status ratings were updated to describe the qualitative probability of a plants
occurrence in a wetland/upland.
- +/- modifiers were removed for FAC species
The 2012 NWPL uses the best available scientific and technical information for improving precision in determining the vegetation factor when delineating upland/wetland boundaries for purposes of Section 404 of the Clean Water Act and the Wetland Conservation Provisions of the Food Security Act. It also provides a procedure for continual future scientific updates and public input as more data are gathered and analyzed. The plant list can be downloaded from the website in its entirety, by ecoregion or by state. A citation for the NWPL will also be available on the web, when finalized.
The Corps will continue to accept suggestions on the 2012 NWPL. Suggestions may be submitted to Mr. Robert Lichvar, Director of the National Wetland Plant List ERDC/ Cold Regions Research and Engineering Laboratory (CRREL), 72 Lyme Road, Hanover, NH 03755 or by e-mail to NWPL@usace.army.mil.
Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands. Biology Report 88(26.1). Washington, DC: U.S. Fish and Wildlife Service.