By Rowland Benjamin

Catahoula Lake, Louisiana USA

Catahoula Lake is the largest freshwater lake in Louisiana, extending 12,150 hectares on the western edge of the Mississippi River. The wetland is large, shallow and poorly drained and is said to be the largest moist soil unit in North America. The State of Louisiana owns the lake and manages it in co-operation with the US Army Corps of Engineers, the U.S. Fish and Wildlife Service and the Louisiana Department of Wildlife and Fisheries.

The water level of Catahoula Lake varies considerably from 4 to 5 feet from July to October, to approximately 25 feet during spring. This seasonal fluctuation makes the wetland an ideal winter breeding ground for a large variety of waterfowl, including canvasback ducks, geese, shorebirds and wading birds, which migrate to the lake in their hundreds of thousands. Duck populations exceeding 400,000 were recorded in the late 1980’s while the number of canvasbacks supported by the lake has accounted for over a quarter of the national canvasback population.

Seasonal water fluctuations also affect the development of fish species. Fish from adjacent rivers enter the flooded lake during winter to spawn; newly hatched fish feed on the aquatic insects and invertebrates which themselves feed on the decay of the flooded vegetation, reintroduced into the lake’s floodplain during winter. Sediments are deposited into the lake at this time, providing vital nutrients for the growth of vegetation. This growth is also supported by the exposure of sediments at the bottom of the lake to oxygen during summer.

As Catahoula Lake dries up during the summer, the drying process helps to firm bottom sediments so that when re-flooded, the bottom provides an excellent spawning substitute for bottom-nesting fish species. As the bottom is exposed to oxygen, bacteria and fungus convert inorganic nutrients in the soil that can be utilised later by aquatic organisms. The exposed bottom supports growth of vegetation that will supply both food and cover for aquatic organisms when flooded.

The major threats to this wetland include development and the construction of flood control, which leads to loss of floodplain habitat and a decline in fisheries.

The Catahoula National Wildlife Refuge had 11,000 visitors in 2003. Although the park was established as a sanctuary for the waterfowl, a large proportion of the visitors come here to hunt and fish. Lead shot deposition was a problem on the lake bed until lead shot hunting for waterfowl was banned in 1987. Proposals have also been made by private land owners to commercially develop the shoreline of the lake, which poses the threat of oil spills and for this reason spill contingency plans are frequently upgraded and pollution control devices installed.

Reduced channel capacity upstream has also affected lake use for waterfowl. In 1972 the Catahoula Lake Diversion Canal was built to provide an outlet from the lake to the Black River downstream. However, the canal has affected the silting of the natural channels and has accelerated the invasion of woody plant growth. As this vegetation has spread across the mudflats, the thick canopy of branches has reduced sunlight exposure which is destroying the habitat and food source of waterfowl. Efforts have been made to reduce the invasion, but these have been slow because of the size of the area affected by the problem, the lack of effective herbicidal treatment and the lack of funding for mechanical eradication.

Mesopotamian Marshlands, Iraq

The Mesopotamian Marshlands are situated at the convergence of the Tigris and Euphrates Rivers in southern Iraq. These marshlands were the largest wetland ecosystem in the Middle East. They played a key role in the intercontinental flyway of migratory birds, supported endangered species and sustained fisheries of the Persian Gulf. In addition to these important ecological benefits, these marshlands represented a unique element of our global heritage and resources. They have been home to indigenous human communities for millennia.

The marshlands once formed a chain of lakes and marshes that flow into one another, and once covered over 20,000 km2 of interconnected lakes, mudflats and wetlands within modern-day Iraq and Iran. During periods of high floods, large tracts of the wetlands were submerged under water. Consequently, some of the formerly separate areas of marshland would merge together during the wet season, forming a large wetland complex.

Between 1970 and 2000 the size of the marshlands were significantly reduced. Over 90 percent of the marshlands were destroyed through the combined actions of upstream damming in Syria, Turkey and Iraq as well as the development of extensive downstream drainage projects within Iraq.

The Tigris and the Euphrates Rivers are among the most intensively dammed rivers in the world. In the past forty years, the two rivers have been fragmented by the construction of more than 30 large dams. By doing this the dams have essentially prevented water from entering areas it otherwise would have, decreasing the water available to the wetlands.

The main cause of the marshland loss however, began during the Iraq-Iran Gulf War where dykes, embankments, and drainage canals were constructed by the two countries as they struggled to gain military advantage over each other by using water as a tool. Following the defeat of the Iraqi army in 1991, the regime of Saddam Hussein constructed diversion canals that deprived the Central and Hammar Marshes of water, in order to reclaim the area for agricultural purposes. These actions caused the land to change and resulted in over 90 percent of the existing marshlands being destroyed in less than 10 years. Without water, the two major marsh areas in the country turned into desert.

Disappearance of marshland habitat has had a catastrophic impact on birds, fish, and mammal species. Species that depended on the habitat, including the smooth-coated otter, bandicoot rat, African Darter and the sacred Ibis, Pygmy Cormorant and Goliath Heron are now extinct.

In addition, drainage of the marshlands has caused the collapse of the Marsh Arab society, an indigenous group of people who have inhabited the marshlands for 5,000 years. The Iraqi government’s assault on the Marsh Arabs occurred at a time when all Shi’a or Shi’ite Muslims were being persecuted, as the authorities feared that the Iraqi Shi’a might follow the example set by the Shi’a in Iran and rebel against the government. In addition to the fact that Marsh Arabs were Shi’a, Iraqi authorities targeted them because the remote terrain of the marshlands provided refuge for political opponents of the regime and because, in 1991, Marsh Arabs themselves took part in rebellion against the Baghdad government. The marshlands also contain great wealth: they are today recognised as the site of some the richest oil deposits in the country. The population of the Marsh Arabs was thought to be around 250,000 people in 1991 but are believed to have been reduced to fewer than 40,000 people by 2006, with many forced to flee and become refugees in Iran.

Uncontrolled releases of Tigris and Euphrates River waters after the 2003 Iraq War partially restored some former marsh areas in southern Iraq, but restoration is failing in other areas because of high soil and water salinities. By 2006 approximately 40 percent of the original marsh area was re-flooded, but the extent of marsh restoration is unknown. Rapid re-establishment, high productivity, and reproduction of native flora and fauna in re-flooded former marsh areas indicate a high probability for successful restoration, provided these marshlands are managed and have continued protection.

Everglades Wetlands, South Florida

The Everglades region is a subtropical wetland located at the southern tip of the Florida peninsular. It is the most famous wetland in the United States and one of the most distinct in the world. The Everglades is unique among the world's large wetlands as it derives its water entirely from rainfall and not from tidal inundations like a lot of wetlands. Several hundred years ago, this wetland was a major part of a 5,184,000 acre watershed that covered almost a third of the entire state of Florida. The Everglades consists of a shallow sheet of fresh water that rolls slowly over the lowlands and through billions of blades of sawgrass. As water moves through the Everglades, it causes the sawgrass to ripple like green waves; because of this the Everglades is nicknamed the “River of Grass”.

The Everglades have changed dramatically throughout history. Originally, the wetlands extended over 3,000,000 acres from Lake Okeechobee to Florida Bay. This territory is often referred to as the "historic" Everglades. The natural land characteristics of this area are highly variable, as it is a patchwork of landscapes, including freshwater marshes, wetland tree islands, pinelands, mangrove swamps, and coastal marine waters. Because of the unique land and water characteristics, the plant and animal life is also extremely specialised to the region. Many plants and animals are only found in the Everglades wetland region, so any changes in the ecosystem threaten the survival of the entire species.

Settlers, who arrived in southern Florida in the early 1900's, drained much of the wetlands to build houses and plant crops. They also channelled the water by constructing over 1,400 miles of canals, levees, and dykes to provide a constant supply of water for themselves, and to protect themselves from frequent deadly floods. Degradation from the use of fertilizers and pesticides has resulted in the invasion of cattalis (Typha sp) and other introduced species such as the Australian tree Melaleuca which has been a minor ecological disaster. Many species of introduced fish and lizards have displaced native species. Since water management controls have been implemented, 56 Everglades plant and animal species are now considered endangered or threatened. Endangered species include the Florida panther, the manatee, the American crocodile, the snail kite, and the Southern bald eagle.

As a result of this significantly modified water flow pattern it is estimated that no more than two percent of the original Everglades ecosystem is truly intact. However, about 30 percent of the Everglades remains in an altered state that could be restored with proper management.

In 1983 a campaign to restore the Everglades was first suggested including the reinstallation of natural flows into the Everglades National Park and the protection of a variety of threatened species to the region. Restoration efforts are now currently being carried out and have focused on large scale changes in water delivery to the Everglades wetlands. These changes include increased water inputs and associated changes in nutrient regimes in a freshwater-estuarine system.

As a result of restoration efforts and improved management of the wetlands the area is slowly recovering. It is not likely the Everglades will ever fully recover to its original extent but with careful management and restoration parts of the wetlands have the potential to recover.

Pantanal, Brazil

The Pantanal is an area of low-lying forests, marshes, and dry plains and covers 200,000 km2 of western Brazil. It is home to a variety of wildlife, including jaguars, anteaters, tapirs and crocodiles. The Pantanal floods in the rainy season, serves as a biogenetic reservoir and supports a large fishery. Although the majority of wetland ecosystems have a role in flood control, the Pantanal wetlands are extremely important as they extensively reduce and delay the height of the flood peak and thus reduce the flood risk downstream. Because of the Pantanal, the flood peak of the Paraguay River is as much as two to three months later than the Paraná River into which it empties, avoiding the cumulative impact of these two flood peaks combining downstream.

The greatest risks for the Pantanal include the intensive agriculture, as well as industrial and urban development. Humans are transforming the area with the industrial farms, mining, roads and dams for hydroelectric power. The area is also under threat from overfishing and tourism as well as the numbers of people moving there to make a living.

In recent years, agricultural development in the Brazilian highlands has been increasing substantially, leading to an accelerated clearing of the land. Already 17 percent of the native vegetation has been destroyed. Continued deforestation at the current rate would cause all of the Pantanal's original vegetation to disappear in 45 years. This deforestation has led to increased erosion and sedimentation of the Pantanal waterways, which in turn increases flood risk, lowers biodiversity and disrupts the overall sediment budgets of the catchment basin. Heavy use of fertilizers, herbicides and pesticides in agricultural activities have also had a major impact, as has the untreated, domestic sewage and garbage that is being discharged into the Pantanal's rivers and wetlands. This adds to the organic loading, sediment and chemical contamination, all of which impacts the wetland. Much of this comes from rapidly-growing domestic centres in the highlands outside of the Pantanal, and particularly in northern Pantanal.

Mining continues to be a significant problem to the Pantanal, especially in the state of Mato Grosso where a lot of gold mining is carried out. Large amounts of mercury are used to strip the gold. Brazil passed a law prohibiting the use of mercury in gold mining in December of 1988, however mercury use and contamination remains a troubling factor as enforcement of the law confronts the reality of many hundreds of digs spread over vast and often isolated areas. High levels of mercury have been found in fish and in fish-eating birds, such as kingfishers and raptors, again significantly impacting the wetland ecosystem.

There is also substantial overfishing taking place. There are a number of laws to regulate fishing, however enforcement is often inadequate. Often a specific species making a migratory run is heavily over-exploited. All of which results in acute or chronic ecosystem disruption and loss of biodiversity. Threatened and endangered animals such as the jaguar, hyacinthine macaw, blue and yellow macaw, red and green macaw (or greenwing macaw), blue-fronted parrot, and toco toucan (Ramphastos toco) are also being captured from the Pantanal to be exported illegally for the Brazilian pet trade, which is also impacting on the biodiversity of the ecosystem.

Increases in the population sizes in the Brazilian highlands and the Pantanal have resulted in increasing sedimentation and erosion of wetland and river systems. Modification of the natural hydrology through construction of local dams and dykes by landowners affects the water flow pattern and increases flooding outside these areas. Proposals to modify the Paraguay River including channel straightening, dredging and damming would lead to large sections of the wetlands being drained and would also result in changes in water flow velocity.

Areas of wetlands in the Pantanal are still in a pristine state, but as the human population expands and attempts to further exploit resources that wetland ecosystems provide or to redirect water away from these environments, the wetlands will be impacted and degraded, possibly even lost as is the case with many other wetlands in the world. We have the potential to protect this environment now for the future, but must do this before they are degraded further.

Rann of Kutch (Kuchchh), India and Pakistan

The Rann of Kutch stretches for almost 2,000,000 hectares along the borders of India and Pakistan. Two areas are recognised, the Great Rann (700,000 hectares in India and 770,000 hectares in Pakistan) and the Little Rann (495,300 hectares).

The Rann of Kutch has been shaped by a variety of geological processes. Once part of the Arabian Sea, geological uplift closed off the area and created a large freshwater lake that was still navigable more than two millennia ago. Over the centuries silting has created a mud flat that is now only flooded during the brief wet season.

For half of the year this area is a vast salt flat and is considered to be a desert rather then a wetland. Between May and October, however, it's a different place altogether. During the monsoon the Rann gets inundated for a period of about one month. The salt flats are flooded with runoff from monsoonal rains and seawater driven by high winds and tides from the Arabian Sea, transforming this desert into marshes teeming with wildlife.

During the wet season, many large mammals also inhabit the few areas of higher ground, which provide a place for the region's only large trees to grow. It is a critically important refuge for the Indian wild ass and is an important staging area for migratory birds. The marshes support over 200 species of birds, including one of the world's largest breeding colonies of greater and lesser flamingos, the threatened lesser florican, cranes, storks, and two endangered bustards waterfowl.

Although part of the wetlands on the Indian side are already protected, the fragile ecosystem is under threat from cattle grazing, vehicular traffic, and tree harvesting to make charcoal. These activities are also still occurring in the protected areas of the Rann of Kutch as India has no ability to implement methods preventing this from occurring, thus despite officially being protected, the environment is still being impacted.

There are also proposals to expand commercial salt extraction into this area as it is a profitable industry in this part of the world. If this occurs it could adversely affect the wild ass population as well as the region's threatened bird species and several other animal populations. Salt extracting will also impact greatly on the wetlands as this activity will not only directly remove the wetlands but increase erosion, indirectly impacting the remaining wetlands.

In 2002 India and Pakistan committed to designate over 1.6 million hectares of the Rann of Kutch as Ramsar sites, wetlands of international importance. These commitments raise the hope that in the future, the two neighbours will work together to protect and manage one of the most biologically important wetlands in Asia. Further protection for the area is vital to ensure this intermittent wetland is not degraded further by human activities.

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