Ecology of the Mississippi River Delta Region

These definitions and characteristic descriptions are taken almost verbatim from Wetlands Training Institute (1991).

DEFINITION:
Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

DIAGNOSTIC ENVIRONMENTAL CHARACTERISTICS:

1. Vegetation: The prevalent vegetation consists of macrophytes that are typically adapted to areas having hydrologic and soil conditions described above. Hydrophytic species, due to morphological, physiological, and/or reproductive adaptations, have the ability to grow, effectively compete, reproduce, and/or persist in anaerobic soil conditions. Indicators of vegetation associated with wetlands are variable, but the strongest case exists when more then 50% of the dominant species are Obligate Wetland Plants (OBL - virtually always occur [.99%] in wetlands), Facultative Wetland Plants (FACW - plants that occur >67%-99% of the time in wetlands), or Facultative Plants (FAC - plants with a similar liklihood [33%-67%] of occurring in wetlands and nonwetlands).
2. Soils: Soils are present and have been classified as hydric, or they possess characteristics that are associated with reducing soil conditions.
3. Hydrology: The area is unindated either permanently or periodically at mean water depths 6.6 ft, or the soil is saturated to the surface at some time during the growing season of the prevalent vegetation.

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