As the world focuses on pressing environmental issues such as climate change, there is a risk that other priorities such as the preservation of wetlands may be overlooked by the general public.

Wetlands is essentially an umbrella term for a wide variety of inland and coastal water features. As places where terrestrial and aquatic ecosystems meet, they are home to a high level of biodiversity, most spectacularly encountered when flooding rains bring large breeding flocks of birds, often waders, ducks, and pelicans. Some Australian wetlands serve as stopover points for migratory birds that have flown vast distances from breeding grounds in Siberia, North Asia and inside the Arctic Circle.

Estuarine wetlands, also known as tidal wetlands, are often home to saltmarsh and mangrove vegetation. Occupying a brackish zone where salt and fresh water flow together, they provide a particularly important habitat for fish and birds. In a sense, they are a type of fish nursery where species such as mullet grow up before later migrating to the ocean.

For humankind, wetlands offer a fresh water supply, better sanitation and a more varied diet. Communities such as Leeton in New South Wales, whose wetlands include Fivebough and Tuckerbill, can boost their economies by providing ecotourist activities for walkers and birdwatchers. Viewed from a broader perspective, wetland areas offer an impressive range of environmental benefits. Often located near important rivers, they filter out pollutants and surplus nutrients from the water and have been described as the kidneys of river systems. When there has been heavy rain, they mitigate flooding of neighbouring ecosystems and protect against erosion.

In 2007, Dr Carmel Schmidt at the University of Adelaide carried out a study based on wetlands adjoining the River Murray and estimated the water filtration they offer is worth $7100 per hectare. Where wetlands have been destroyed, the solution has often been to build in their place expensive water treatment facilities with ongoing running costs.

A history of wetland loss

Sadly, wetlands have traditionally had a bad image and were often perceived as little more than breeding grounds for mosquitos that spread diseases to nearby villages. Historically, around the world large areas of wetland have made way for agriculture, industry and human settlement. Perhaps the most extensive example involves the loss of the enormous floodplains of South-East Asia when they were converted to rice-growing paddy fields.

Other wetland areas became degraded as human impact impaired their ability to maintain various natural functions. The removal of vegetation results in fewer habitats for fauna and reduces a wetland’s capacity to protect against salinity and erosion. Agricultural chemicals such as fertilisers and pesticides may harm plant and bird communities. An excess of nutrients can lead to toxic algal blooms, which may cause fish to die from a lack of dissolved oxygen in the water.

In recent decades, three under-reported large-scale wetland disasters have been occurring in different corners of the planet. Fortunately, in each case there are some grounds for cautious optimism.

Rainforest-covered peat swamp found on the island of Borneo is being destroyed to make way for Indonesian and Malaysian palm oil plantations and the process is accelerating. This loss is a major contributor to climate change through forest burning (CO2) as well as via the decomposition of organic matter (methane). An activist group called Wetlands International is working on several projects to help protect the island’s remaining peat swamp forests.

In Central Asia, two large rivers known as Amu Darya and Syr Darya were harnessed during the Soviet era for large-scale irrigated cotton programs in Uzbekistan and Kazakhstan. In addition to drying up the Aral Sea, this has caused many wetlands that formerly existed in the deltas of both rivers to disappear. Current rehabilitation work is focused on important wetlands that surround Lake Sudoche in the Amu Darya delta, a staging ground for endangered migratory birds.

Satellite photos taken in the early 1990s showed that Saddam Hussein was draining the renowned marshes of southern Iraq. This area, which lies between the Tigris and Euphrates rivers, was once known as Mesopotamia and may have been the location of the Garden of Eden. Iraqis living in the US formed an NGO called Eden Again and, since the 2003 invasion, rehabilitation work has been continuing in spite of the many security issues. Today the marshes are steadily recovering.