There is clear water up to your ankles and a dragonfly zips past your head as you watch some ducks fly off the water - welcome to the soggy world of the wetland!

Wetlands are difficult to define because of their great variation in size and location. The most important features of wetlands are: Waterlogged soils or soils covered with a shallow layer of water (permanently or seasonally), unique types of soil, and distinctive plants adapted to water-saturated soils. Marshes, bogs, swamps, vleis and sponges are examples of wetlands.

WHY ARE WETLANDS IMPORTANT?

* Flood busters:
Wetlands associated with streams and rivers slow floodwaters by acting as giant, shallow bowls. Water flowing into these bowls loses speed and spreads out. Plants in the wetland play an important role in holding back the water. The wetland acts as a sponge as much of the flood water is then stored in the wetland and is slowly released to downstream areas, instead of it all rushing to the sea within a few days. This greatly reduces flood damage, particularly erosion, and ensures a more steady supply of water throughout the year.

* Filters:
Wetlands improve water quality as they are very good natural filters, trapping sediments, nutrients (e.g. nitrogen and phosphorus), and even pathogenic (disease-causing) bacteria. In addition, pollutants such as heavy metals (e.g. mercury, lead) and pesticides, may be trapped by chemical and biological processes. In other words, the water leaving the wetland is cleaner than the water entering it.

* Wetlands and wildlife:
Wetlands are filters where sediments and nutrients accumulate, so many plants grow there, e.g. bulrushes, grasses, reeds, waterlilies, sedges and trees. The plants, in turn, provide food and a place for attachment and shelter for many creatures. There is more life, hectare for hectare, in a healthy wetland than in almost any other habitat. These productive places support huge numbers of insects, fish, birds and other animals. Some animals are completely dependant on wetlands, whilst others use wetlands for only part of their lives. The wattled crane, for example, is dependant on wetlands for breeding. The rich diversity of waterbirds in southern Africa (totalling 130 species) is possible because of the many wetlands spread across the sub-continent. The wetlands of southern Africa are of international importance as they are the southern destination for many migratory wading birds.

* People and wetlands:
Wetlands have been used for centuries as grazing for domestic stock, and as a source of reeds used for thatching, hut construction and basket weaving. They are provide fishing, hunting and the opportunity to observe wildlife, especially birds. Wetlands are appreciated for their beauty as open spaces and also for their educational value.

WETLANDS IN TROUBLE

To most people words such as "marsh, swamp, bog and vlei", conjure up little more than the "four D's" - dampness, disease, difficulty and danger. Because of this wetlands have been seen as wastelands to be converted to alternative uses such as cropland, dams, plantations of exotic trees, waste disposal sites and pastures. Many wetlands have been "reclaimed" for industry and the construction of airports, harbours and sewage treatment plants. Historically wetlands have been drained in attempts to control malaria.

All wetlands in southern Africa are threatened. Botswana's magnificent Okavango Delta is threatened by the possible canalization of the Boro river to supply water for both domestic and industrial use. In KwaZulu/Natal, debate rages over the mining of the dunes on the eastern shores of St. Lucia because of the unknown consequences to the water table in the area.

St. Lucia is a Ramsar recognised site. The Ramsar Convention on Wetlands of International Importance recognises such wetlands and works to conserve them. South Africa has 12 sites recognised by the Ramsar Convention, including Langebaan on the west coast, Barberspan in Gauteng and De Hoop vlei in the Cape.

WHAT YOU CAN DO

* The Department of Environment Affairs and Tourism runs a wetland conservation programme and all interested people are invited to participate.

* Get to know the wetlands in your area and list the plants and animals growing there. Draw a map of the wetland's position, size and usage. Take photographs of the wetlands from fixed vantage points and at different seasons of the year to compare the changes between seasons and from year to year.

* Report the abuse of wetlands to your local nature conservation, agricultural extension officer or Department of Environment Affairs. Always make your report in writing to ensure that the officer concerned has to investigate.

* Read "The Biology and Conservation of South Africa's Vanishing Waters" (see below) which has a very useful chapter titled "What you can do".

DID YOU KNOW?

* In KwaZulu/Natal, 58% of the wetlands associated with the Mfolozi River catchment have disappeared as a result of siltation caused by erosion of overgrazed lands.

FURTHER READING

SOUTH AFRICAN WETLANDS. Newsletter on the activities relating to the Ramsar Convention in South Africa. Department of Environment Affairs.

THE WETLANDS OF NATAL (PARTS 1-4). Natal Town and Regional Planning Commission. Private Bag 9038, Pietermaritzburg, 3200.

ECOLOGY AND CONSERVATION OF WETLANDS IN SOUTH AFRICA. CSIR occasional report no.56. CSIR 1982. Waterlogged Wealth. E. Maltby, Earthscan,1986.

WETLANDS. C. Gaigher. Dept. Environment and Cultural Affairs (previously Cape Nature Conservation).

THE BIOLOGY AND CONSERVATION OF SOUTH AFRICA'S VANISHING WATERS. B.R. Davies and J.A.Day. CEMS, University of Cape Town and The Wildlife Society of Southern Africa, Cape Town, 1986.

Enviro Facts: River Catchments.

USEFUL ADDRESSES

The Department of Environment Affairs and Tourism. Private Bag X447, Pretoria 0001. Tel. 012-310 3425.

All provincial nature conservation authorities.

Universities of Cape Town, Orange Free State, KwaZulu/Natal, Witwatersrand and Rhodes.