Wetland Definitions Chapter 2
Features of Wetlands • All wetlands, by definition, have some level of standing water for some period of time. • Wetlands must also have vegetation which can tolerate water saturation for extended periods of time (like Cyprus trees here in LA) • Wetlands also have soil different from that of the surrounding areas.
Wetland Terms • Wetlands have terms like: Swamp, Bog, Marsh, Mire, etc. • But these are not necessarily accurate. The definitions are constantly changing and different countries, and even areas of the US, have different terms for the same thing.
Where are Wetlands Found? • Wetlands are found between terrestrial and aquatic systems • In the case of Louisiana, they are often found between the forest and ocean.
Components of Wetlands • Wetlands must have the presence of water for at least a significant period of time. • This can be at the surface or root level • Soil conditions must be different from adjacent areas • It must contain hydrophytes (plants that like water)
(Gosselink, 1993) Although wetlands are considered highly productive and nutrient rich. cypress swamps are considered an exception to this.
Hydrology ↓ Soils, chemical makeup of area ↓ ↓ Vegetation ↓ ↘ Animal Life
Definition of Wetlands Not Always Clear • Some wetlands are constantly flooded, and some only briefly and intermittently. Sometimes the land can be dry but the soil is saturated. • Wetlands are influenced by both aquatic and terrestrial systems so they could evolve into one or the other.
At what size do we consider something to be a wetland? Sometimes they can be only an acre. • Organisms there can be Obligate (adapted only to a wet environment) or Facultative (adapted to dry land) . • Wetlands can be created or destroyed by man.
Wetland Types • Riparian Ecosystems- the are found close to aquatic systems (usually a river or stream). They are sometimes called a bottomland hardwood forest.
Swamps- Support woody plants like trees or shrubs. • Vernal Pools- are flooded meadows. They are usually temporarily flooded in the spring. • Marshes • A deep water march usually has more than 10 inches of water • Salt water marshes contain brackish water and is usually tidal • freshwater marshes are often found at the mouth of rivers and are typically non-tidal
Peatlands- collect partially decaying plant matter. • Bogs supports moss- especially Sphagnum moss. • Fens are more like a marsh with some drainage from nearby areas. They usually do not contain moss.
More precise definitions come from two places: wetland scientists and federal agencies. • The following is from the National Research Council • "The term 'wetland' excetpt where such term is part of the term 'converted wetland' means land that -(A) has a predominance of hydric soils;(B) is inundated or saturated by surface or ground water at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation typically adapted for life in saturated soil conditions; and (C) inder normal circumstances does support a prevalence of such vegetation.For the purposes of this Act and and other Act, this term shall not include lands in Alaska identified as having high potential for agricultural development which have a predominance of permafrost soils." • Below is from the Army Corp of Engineers. 33 CFR 328.3 • The term wetlands means 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.