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New National Wetland Plant List
Effective June 1, 2012, a new wetland plant list (NWPL) will be made available by the U.S. Army Corps of Engineers, in cooperation with the U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service and the U.S. Department of Agriculture Natural Resources Conservation Service. The NWPL is used to determine whether the hydrophytic vegetation parameter is met when conducting wetland determinations under Oregon’s Removal-Fill Law, the Clean Water Act, and the Wetland Conservation Provisions of the Food Security Act.
Any field work completed on or after June 1, 2012, will need to use the new list. However, work performed before this date may also use the new list. DSL will accept determinations and delineations based on the former indicator status list only if the field work was completed before June 1. It is important that any delineation work performed before June 1 reference which list was used. 
The wetland plant list was first published by the U.S. Fish and Wildlife Service in 1988 and contained 6,728 species. The latest list contains 8,200 species, an increase of 1,472 species, or 22 percent. The majority of the increase is a result of new taxonomic interpretations. The new list also includes changes in plant indicator status (OBL, FACW, FAC, and FACU designations) from 1988 for 807 species, or 12 percent of the list (not including the new species added to the list). The specific changes include: 35 percent (282 species) were rated wetter; 36 percent (290 species) were rated drier; and the remaining 30 percent (235 species) were changes to the former FAC-group.
The updating procedures designated a more stringent review of the former 1988 FAC-species.  Of these former FAC-species, half were rated FACU and half were rated as FAC by a panel of 30 external professional botanists across all regions. Thus, the overall distribution of changes was nearly an equal split between species that received wetter ratings and those that received drier ratings.