Km2 Of Wetlands Research Articles

Wetland Loss in World Deltas

Geologic and geomorphic data on 42 world deltas were compiled for a NASA-sponsored research project. Satellite images from 14 of these deltas (Danube, Ganges, Brahmaputra, Indus, Mahanadi, Mangoky, McKenzie, Mississippi, Niger, Nile, Shatt el Arab, Volga, Huang He [Yellow], Yukon, and Zambezi) were analyzed for delta plain wetland loss caused by natural causes and conversion of wetlands for agricultural and industrial use. These analyses indicated that a total of 15,845 km2 of wetlands have been irreversibly lost during the past 14 years and the average rate of loss is 95 km2/y. If a similar trend is present in the other deltas, a total wetland loss in the delta plains of the 42 deltas would be on the order 364,000 km2 over the past 15 to 20 years.

Applying science to conservation and restoration of the world's wetlands

The world has an estimated 7 to 9 million km2 of wetlands which can be defined through their hydrology, physiochemical environment, and biota. Many human cultures have lived in harmony with wetland environments for centuries. Many others have not, resulting in drainage or severe impact of wetlands throughout the world. Conservation of wetlands needs to be a priority for the cultural and ecological values they provide. But a more optimistic note is that large-scale restoration and re-creation of wetlands and riverine systems is beginning to happen throughout the world through ecological engineering. Examples of large-scale wetland restoration projects are presented for Delaware Bay, the Skjern River (Denmark), Florida Everglades, Louisiana Delta, the Mississippi River Basin, and the Mesopotamian Marshlands of Iraq.

Distribution of waterfowl in the wetland of Northern Nigeria

Agbelusi, E.A. & Afolayan, T.A. 2000. Distribution of waterfowl in the wetland of Northern Nigeria. Ostrich 71 (1 & 2): 73. Nigeria with a land area of 923 850 km2 has approximately 24 000 km2 of wetland. These wetlands are scattered all over the country and include the man-made lakes. The wetlands of northern Nigeria are important breeding sites for Afrotropical duck and also serve as the winter refuge for Palearctic birds from Europe. About 13 sites have been identified as the actual habitat and concentration points for waterfowl in the wetlands of northern Nigeria. Among these areas, the Hadeija-Nguru wetland represents one of the most productive and ecologically significant wetlands in Nigeria. This area supports about 58 000 waterbirds, belonging to about 376 species, which consist mostly of Palearctic and Afrotropical migratory birds. Some of the important bird species that are associated with the wetland of northern Nigeria are Black Crowned Crane, Pintail, White Pelican, White-faced Tree Duck, Knob-billed Goose, Spur-winged Goose, Gull-billed Tern and Saddle-billed Stork. The paper also discusses the management implications for waterfowl conservation and tourism in Nigeria.

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km2 Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km2 of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y1. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y1 in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y1. The potential retention by wetlands was estimated to 57,000–145,000 ton y1 when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y1. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.

LOUISIANA'S ERODING COASTAL ZONE: MANAGEMENT ALTERNATIVES

SUMMARY The wetlands and protective barrier islands of coastal Louisiana are deteriorating and eroding at rates of crisis proportions. Annually Louisiana loses 130 km2 of wetlands. This high rate of coastal land loss is due to both natural and man-induced causes. Louisiana's coastal wetlands and barrier islands owe their existence to the delta cycle of the Mississippi River. Innate in this cycle is the natural deterioration of wetlands and barrier islands along one segment of the coastal zone as initiation and expansion of wetlands and barrier island occurs along others. Hence, during the last 7000 years a net gain of land of 500 to 600 ha annually has resulted. Since 1900, however, there has been a net annual loss of land. This paper discusses (a) the effect of man's activities on the natural delta cycle and, as a consequence, rates of coastal deterioration and (b) the potential mitigative measures which may be utilized to ameliorate this effect.