Wetland Plant List Updated

June 2012Articles In the Zone

On May 18, 2012, the U.S. Army Corps of Engineers, Pittsburgh District, announced 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. This update represents the most complex and thorough evaluation of wetland plant species ratings since the inception of the 1988 list.

Specific changes include:

  • Providing the status ratings of more than 8,200 plants
  • A dedicated website that includes photos, previous status ratings and other botanical information
  • Updated nomenclature for more than 2,400 plants
  • Eco-regions 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 plant’s occurrence in a wetland/upland.
  • +/- modifiers were removed for FAC species

The 2012 NWPL as well as related background information can be found online.