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Wetlands

Wetland Plants and Fungi

Surf grass (Phyllospadix) in the intertidal zone

Surf grass (Phyllospadix) in the intertidal zone
(Gayle Hansen, Newport, Oregon)

About one-third (ca. 1,600 species) of Oregon's flowering plants, liverworts, and mosses grow in or adjacent to wetlands. Of these 1,600 species, between 300 and 400 (20-25 percent) are restricted to wetlands and require perennial or seasonal soil moisture for survival. These plants range from aquatic species such as pond lily, water milfoil, sago pondweed, and fountain moss to emergent sedges, rushes, bulrushes, and sphagnum moss. All of the estimated 425+ species of seaweeds reported from Oregon are aquatic. Many species of fungi also are restricted to wetlands. This tremendous amount of living material, and the dead litter that it produces seasonally, creates habitat structure and provides food and cover for a multitude of other species ranging from microbes to mammals. It also helps regulate nutrient cycling, pH, water and soil chemistry, and water storage.

Oregon Wetland Plant List

Since 1988, several versions of the National Wetland Plant List (NWPL, see below) have been produced, each with somewhat different content and legal implications. To avoid confusion, the Oregon Department of State Lands requires the use of combined 1988 and 1993 NWPL lists. This list was compiled in 2009 and is the most up-to-date list to use for field work in Oregon.

National Wetland Plant List

Because wetland plants are stationary, conspicuous, and relatively easy to observe and measure, they are very useful tools in wetland science. The NWPL, originally developed by the U.S. Fish and Wildlife Service and since 2006 managed by the U.S. Army Corps of Engineers, was developed to help standardize the use of plants as wetland indicators. By assigning a wetland indicator status (e.g., Obligate, Facultative, Upland) to each species, it helps wetland regulators, consultants, and scientists to determine whether vegetation at a site meets wetland criteria as defined in the 1987 Corps of Engineers Wetlands Delineation Manual and supplements for western Oregon and eastern Oregon.

The NWPL is being revised by the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the U.S. Environmental Protection Agency, and the Natural Resources Conservation Service. The updated NWPL may be available in 2010. For those who want to see the various versions of the NWPL, the 1988 and 1996 lists are available on the Corps of Engineers National Wetland Plant List (NWPL) website.

Authored by John A. Christy, Portland State University-INR (2012).

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