Wetland Indicator Plants 

A wetland is an area of land that is covered by water either seasonally or permanently. To determine if a wetland is a wetland you can look at the soils or the vegetation. Wetlands can be in one of three categories, swamps, marshes, and bogs. Wetlands create their own distinct ecosystems home to a diverse range of wild life.

Wetland soils: Wetland soils contain high amounts of anaerobic bacteria. These bacteria move electrons in order to gain energy and because these bacteria are anaerobic they do not use O2 (oxygen) for respiration. Instead of using O2 these bacteria use nitrate (NO3-), ferric iron (Fe3+), manganese (Mn2+), sulfate (SO4 2- ) and carbon dioxide (CO2). The most prevalent compound in soils is ferric iron. These bacteria change from the yellowish red non water soluble ferric iron to Fe2+ that is colorless and water soluble. This process causes the soil to lose its reddish yellow color in wetland zones. Anaerobic bacteria also reduce SO42- to H2S (hydrogen sulfide) producing the characteristic rotten egg odor in certain wetland areas.

There are many different classes of plants that indicate the presence of wetlands:

·         Obligate Wetland Plants or OBL Plants: Are very likely to be present in wetlands under natural conditions (estimated probability >99%). However these pants only rarely grow outside of wetlands (estimated probability >1%). Examples: smooth cordgrass, bald cypress

·         Facultative Wetland Plants or FACW Plants: Occur usually (estimated probability >67% to 99%) in wetlands that are under natural conditions. These plants are also unlikely to occur outside of wetlands but still do on occasion (estimated probability 1% to 33% in non-wetlands). Examples: green ash, Red-osier dogwood, sweet pepperbush (seen on at the right)

·         Facultative Plants FAC Plants: Occur with a similar likelihood as FACW plants (estimated probability 33% to 67%) of occurring in both wetlands and non-wetlands. Examples: honey locust, common greenbrier

·         Facultative Upland Plants or FACU: Plants that occur sometimes (estimated probability 1% to <33%) in wetlands, but prefer to grow outside of wetlands where conditions are more favorable for them (estimated probability >67% to 99%). Examples: red oak, tall cinquefoil

·         Obligate Upland Plants or UPL Plants: Have an incredible low tolerance of wet lands and rarely occur in them (estimated probability <1%). These plants favor non-wetlands and almost exclusively grow outside of wetlands (estimated probability >99%). Examples: shortleaf pine, soft brome