US Army Corps of Engineers

Memorandum of Agreement (MOA) to Update and Maintain the National Wetland Plant List

MOA to Update & Maintain the NWPL

Published June 15, 2017
Example of a species on the National Wetland Plant List

Example of a species on the National Wetland Plant List

Background: The purpose of the MOA among the U.S. Army Corps of Engineers (USACE), U.S. Environmental Protection Agency (EPA), U.S. Fish and Wildlife Service (FWS), and the Natural Resources Conservation Service (NRCS) is to maintain and update the National Wetland Plant List (NWPL) and to provide for the transfer of Plant Data from the NRCS-National Plants Database (PLANTS) for future updating and maintenance of the NWPL.

The NWPL plays a critical role in wetland determinations under the Clean Water Act and the Wetland Conservation Provisions of the Food Security Act. Wetlands are evaluated using three factors – soils, hydrology, and vegetation in accordance with the 1987 Wetland Delineation Manual and Regional Supplements. The NWPL is used in evaluating the vegetation factor.

The NWPL is a list of wetland plants and their assigned indicator statuses. An indicator status reflects the likelihood that a particular plant occurs in a wetland or upland. The five indicator statuses are: Obligate (OBL) plants that always occur in standing water or in saturated soils; Facultative Wet (FACW) plants that nearly always occur in areas of prolonged flooding or require standing water or saturated soils but may, on rare occasions, occur in non-wetlands; Facultative (FAC) plants that occur in a variety of habitats, including wetland and mesic to xeric non-wetland habitats but commonly occur in standing water or saturated soils; Facultative Upland (FACU) plants that are typically found in upland habitats but can on occasion occur in standing water or saturated soils; and Upland (UPL) plants that rarely occur in water or saturated soils. The list is web-based which allows for ease of access to users and the ability to make changes to this dynamic list more readily.

This MOA will allow the taxonomy, synonymy, and biogeography of the NWPL to be consistent with the PLANTS database. Currently, the plant data used in the NWPL is not sourced by a Federal Agency which makes it difficult to ensure consistency. Specific provisions in the MOA include: 1) collaboration between USACE and NRCS to provide consistent taxonomy and nomenclature for all wetland plants currently in the NWPL, 2) to enhance the biogeographical distribution data associated with each species in the NWPL, 3) provide current wetland indicator status designations for each species by geographic region to the PLANTS database, 4) to provide the list of upland species and their supportive data for all upland plants not currently on the NWPL, 5) share updates from each system on a 2-year cycle and 6) provide photos currently found in the PLANTS database for use in the NWPL.

The NWPL can be found at: