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Landscape ecology has been cited as a contributor to the development of fisheries biology as a distinct biological science discipline, [51] and is frequently incorporated in study design for wetland delineation in hydrology. [39] It has helped shape integrated landscape management. [52]
The techniques used by NWI have recently been adopted by the Federal Geographic Data Committee as the federal wetland mapping standard (FGDC Wetlands Subcommittee 2009). This standard applies to all federal grants involving wetland mapping to insure the data can be added to the Wetlands Layer of the National Spatial Data Infrastructure.
A simplified definition of wetland is "an area of land that is usually saturated with water". [14] More precisely, wetlands are areas where "water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season". [15]
The wetland status of 7,000 plants is determined upon information contained in a list compiled in the National Wetland Inventory undertaken by the U.S. Fish and Wildlife Service and developed in cooperation with a federal inter-agency review panel (Reed, 1988). The National List was compiled in 1988 with subsequent revisions in 1996 and 1998.
Determining the boundary of wetland, whether jurisdictional under sections 404 or 10, or not jurisdictional but still meeting the technical definition of a wetland, that is having the soils, vegetation and hydrology criterion met is called a "wetland delineation", and generally is performed by college graduates with natural science or biology ...
Plant community composition can change dramatically over a gradient of groundwater depth: plants that can only survive in wetland conditions can be replaced by plants that are tolerant of drier conditions as groundwater levels are reduced, causing habitat community shifts and in some cases complete loss of riparian species. [7]
A wetland (aerial view) Wetland conservation is aimed at protecting and preserving areas of land including marshes, swamps, bogs, and fens that are covered by water seasonally or permanently due to a variety of threats from both natural and anthropogenic hazards. Some examples of these hazards include habitat loss, pollution, and invasive species.
Wetlands have decreased by as much as 50% since 1900 and in some parts of the world by 90%. [19] [20] Inland wetlands, freshwater marshes making up about 20-25% of all freshwater wetlands globally, [21] have been decreasing approximately 1.2% each year throughout the last century (since 1900). [22] [23]