Drying wetlands

  • 14/06/1998

Drying wetlands water means life, and wetlands, even those such as ponds and bogs, play a vital role in our lives. Found almost everywhere, wetlands can be described as ecosystems where water and land meet, such as marshes, shallow coastal estuaries, mangroves and lakes where the dominating factor is a regular or seasonal abundance of water. And it is here, at the edge of water, that life bloomed and is sustained even today in its various manifestations because of which watery environment is among the most fertile on the planet.

It is, therefore, to be hoped that the steps announced by the government to conserve some wetlands will be implemented earnestly. This is particularly desirable since wetlands provide us with raw material for legends galore as well as raw materials for our own survival.

For instance, wetlands can produce up to eight times as much plant matter as wheat fields.Moreover, species which grow in tidal areas and then swim out to the open sea account for two-thirds of the global fish harvest. It must also be kept in mind that, since the dawn of history, man has settled by the water to fish in wetland waters or avail of the rich soil. Many of the flourishing ancient civilisations were largely dependent on the productivity of wetlands.

The Sunderban mangroves produce nearly 80 per cent of the region's fish. Calcutta has no plant to treat chemical wastes, but it does have extensive 'salt lake' wetlands which are in danger of being stamped out by man even though they have, for 50 years or so, naturally 'treated' the city's sewage and supported fish farms whose annual output is 6,000 tonnes.

Tropical mangroves can provide honey, crustaceans, fish, fuel, alcohol, textiles, paper products, sugar, construction materials and fodder. Besides, they also render signal service in affording protection against coastal and river-bank erosion, reducing flood damage, removing waste besides providing research material to the education and tourism departments. They are also excellent wildlife habitats. Furthermore, leeches, vilified bloodsuckers now emerging as a saviour of mankind, are also found in swamps and bogs.
Learning from leeches This pharmacopoeia from the wetlands is being prescribed by physicians to cure "nearly everything, including headache, fever, insomnia, ulcers and obesity." Of the 650 known species, Hirudo medicinalis, the European medicinal leech, is reckoned the most useful to man and commands a price of us $470 per kilogramme. Unsurprisingly, a growing number of human admirers are rallying round the leech, not only to save it in the wild but also to propagate the species in captivity.

Loving the leech is only a small part of it. If some entrepreneurs have their way, we could soon be following a precedent set by the Aztecs by eating algae, 22,000 species of which constitute the rich organic stew of aquatic slime, a natural product of wetland ecosystem. The staple of the future might be spiruline which flourishes in saline, often alkaline, wetland waters. It is 70 per cent protein, yields more iron per acre than soyabeans, is rich in vitamin BI2 and is a hot and expensive commodity in American health food stores. What's more, it grows faster than a teenager.
Blessing in disguise Another wetland nuisance is water hyacinth, the 'beautiful blue devil', as it is known in our country. It doubles it biomass every eight days and clogs waterways around the world. Yet, it is one of the most useful plants we have.

The water hyacinth effectively filters waste water. It is used all over the world to treat effluents in Chennai, it is used to eliminate tannery effluents while it is used to clean waste water from sugar refineries and rubber processing plants in Malaysia. In Disneyland, Florida, five football field-sized canals filled with water hyacinths clean and recycle water. Also in the US, methane from the hundred-hectare water hyacinth farm provides enough energy to provide electricity in 15,000 houses. The plant is also used to produce fertiliser, cooking gas and building materials. Furthermore, water hyacinth pulp is used to make cement boards in India.

The ancient civilisations that inhabited the great river valleys the Nile, the Indus, the Tigris relied on periodic flooding in the river basin that left a residue of rich alluvial soil on which they could farm. Today, we tend to treat mud like dirt. In fact, the wetlands impressive productivity is attributable to mud; some scientists consider mud, not seawater, as the grandmother of ecosystems. A combination of dirt and water, viscous wetland soil, is generally replete with malodorous organic detritus, a major fish food, and is an ideal breeding ground for single-cell plants and animals that are important elements at the base of the food chain.

Outside the classroom
The intangible values of wetlands must also be taken into account. It is not in the classroom that a child can be shown plovers and frogs. The thrill of watching the first flight of geese across the sky in autumn is normally possible only near the lakes. The gleam in an angler's eyes as he watches a fish rise says that this sport means more to him than ogling at high-rise complexes. However, wetlands are being filled in, poisoned and drained because they are reckoned by many to be wastelands which can be used for a 'better purpose', for instance constructing a multistoreyed housing block.

There is no denying that some wetlands can be drained for agricultural purposes, building sites and other uses. But a new approach must be proposed to evaluate wetlands. Their greatest enemies are pollution, drainage and large dams that alter the water regime, either drying out the wetlands or allowing saline sea water to infiltrate inland. A case in point is Egypt's Aswan dam.

The Sunderban mangroves are endangered, partly because excessive water from the Ganga is being extracted for irrigation and watersheds are being denuded of forests resulting in erratic flow of water.

Some ecologists are of the opinion that the mangroves are becoming more saline, their productivity is diminishing and their effectiveness as a barrier against coastal storms is becoming increasingly debatable. Furthermore, scientists believe that incidents of tiger attacks on humans in the Sunderbans can be ascribed to the rising salinity of the water.

Saving the liquid asset
To save the earth's liquid assets, a worldwide campaign launched jointly by the International Union for Conservation of Nature and Natural Resources (iucn) and the Worldwide Fund for Nature (formerly World Wildlife Fund) is currently under way. Although, rarely a tear has been shed at the demise of a wetland, the problem of wetlands is one of public relations. A better understanding of bio-chemistry may not make swimming with leeches exciting, but it will help us understand its role in curing some of our ills and, therefore, providing an argument for saving its habitat - the wetlands.

Zafar Jordan is a wildlife expert based in Lucknow.

Related Content