Wetland classification
Classification of wetlands has been a problematical task, with the commonly accepted definition of what constitutes a wetland being among the major difficulties. A number of national wetland classifications exist. In the 1970s, the Ramsar Convention on Wetlands of International Importance introduced a first attempt to establish an internationally acceptable wetland classification scheme.[1]
Ramsar classification
[edit]The Ramsar classification of wetland types is intended as a means for fast identification of the main types of wetlands for the purposes of the convention.[2]
The wetlands are classified into three major classes:
- Marine/coastal wetlands
- Inland wetlands
- Human-made wetlands
These are further subdivided by the type of water: fresh / saline / brackish / alkaline; and may be further classified by the substrate type of other characteristics.
National systems of classification
[edit]Australia
[edit]Wetlands in Australia that considered to be of national importance are so classified by criteria published in association with the Directory of Important Wetlands in Australia (DIWA).[3]
The following list is that used within Australia to classify wetland by type:[4]
- A—Marine and Coastal Zone wetlands
- Marine waters—permanent shallow waters less than six metres deep at low tide; includes sea bays, straits
- Subtidal aquatic beds; includes kelp beds, seagrasses, tropical marine meadows
- Coral reefs
- Rocky marine shores; includes rocky offshore islands, sea cliffs
- Sand, shingle or pebble beaches; includes sand bars, spits, sandy islets
- Intertidal mud, sand or salt flats
- Intertidal marshes; includes saltmarshes, salt meadows, saltings, raised salt marshes, tidal brackish and freshwater marshes
- Intertidal forested wetlands; includes mangrove swamps, nipa swamps, tidal freshwater swamp forests
- Brackish to saline lagoons and marshes with one or more relatively narrow connections with the sea
- Freshwater lagoons and marshes in the coastal zone
- Non-tidal freshwater forested wetlands
- B—Inland wetlands
- Permanent rivers and streams; includes waterfalls
- Seasonal and irregular rivers and streams
- Inland deltas (permanent)
- Riverine floodplains; includes river flats, flooded river basins, seasonally flooded grassland, savanna and palm savanna
- Permanent freshwater lakes (> 8 ha); includes large oxbow lakes
- Seasonal/intermittent freshwater lakes (> 8 ha), floodplain lakes
- Permanent saline/brackish lakes
- Seasonal/intermittent saline lakes
- Permanent freshwater ponds (< 8 ha), marshes and swamps on inorganic soils; with emergent vegetation waterlogged for at least most of the growing season
- Seasonal/intermittent freshwater ponds and marshes on inorganic soils; includes sloughs, potholes; seasonally flooded meadows, sedge marshes
- Lakeshore mudflats in freshwater lakes and ponds
- Permanent saline/brackish marshes
- Seasonal saline marshes
- Shrub swamps; shrub-dominated freshwater marsh, shrub carr, alder thicket on inorganic soils
- Freshwater swamp forest; seasonally flooded forest, wooded swamps; on inorganic soils
- Peatlands; forest, shrub or open bogs
- Alpine and tundra wetlands; includes alpine meadows, tundra pools, temporary waters from snow melt
- Freshwater springs, oases and rock pools
- Geothermal wetlands
- Inland, subterranean karst wetlands
- C—Human-made wetlands
- Water storage areas; reservoirs, barrages, hydro-electric dams, impoundments (generally > 8 ha)
- Ponds, including farm ponds, stock ponds, small tanks (generally < 8 ha)
- Aquaculture ponds; fish ponds, shrimp ponds
- Salt exploitation; salt pans, salines
- Excavations; gravel pits, borrow pits, mining pools
- Wastewater treatment; sewage farms, settling ponds, oxidation basins
- Irrigated land and irrigation channels; rice fields, canals, ditches
- Seasonally flooded arable land, farm land
United States
[edit]Wetlands of the United States are classified according to the U.S. Fish and Wildlife Service's National Wetlands Inventory (NWI).[5]
In the US, the best known classification systems are the Cowardin classification system and the hydrogeomorphic (HGM) classification system.
See also
[edit]References
[edit]- ^ Scott, D. A.; Jones, T. A. (1995). "Classification and inventory of wetlands: A global overview". Vegetatio. 118 (1–2): 3–16. doi:10.1007/BF00045186. S2CID 24404467.
- ^ "Ramsar Classification System for Wetland Type"
- ^ "Directory of Important Wetlands in Australia". Commonwealth of Australia. Retrieved 7 October 2015.
- ^ "A Directory of Important Wetlands in Australia: Third edition, Chapter 2: Wetland classification system, Criteria for inclusion and Data presentation". Australian Department of the Environment. 2001. Retrieved 30 March 2021.
- ^ "Wetlands Digital Data". Archived from the original on 2008-05-14. Retrieved 2009-02-10.