The environmentalists highlight the importance of wetlands every year on 2 February when we celebrate World Wetlands Day. This day marks the date of the adoption of the Convention on Wetlands on 2 February 1971, in the Iranian city of Ramsar on the shores of the Caspian Sea.
Appropriately on 01 February 2022 South Africa proclaimed a new addition to the Ramsar List of Wetlands of International Importance. The Berg Estuary on the west coast is the 28th “Ramsar Site” in South Africa. The designation as a Ramsar site the wetland recognises the site’s international significance in terms of ecology, botany, zoology, limnology (study of lakes) or hydrology (study of earth’s water).
According to the South African National Water Act a wetland is “land which is transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is periodically covered with shallow water, and which land in normal circumstances supports or would support vegetation typically adapted to life in saturated soil”.
How to identify a wetland
You will know you are dealing with a wetland if the soil is wet and if you find wetland plants such as bulrush, papyrus, iKhwane grass, iNcema or red swamp grass growing in the area.
Wetlands are occur where the shape and structure of the earth’s surface slows down or obstructs the movement of water through the catchment, so that the surface soil layers in the wetland area temporarily, seasonally or permanently wet. This provides an environment where particular plants (e.g. reeds) that are adapted to wet conditions tend to grow in abundance. The plants, in turn, affect the soil and its water content (e.g. by further slowing down the movement of water and by producing organic matter that may be accumulated in the soil). The plants provide shelter and food for particular animal species.
Why are wetlands important?
Because a wetland slows down the movement of water, it is particularly helpful in preventing floods. A further benefit of a wetland emerges in times of drought, when the wetland is a source of stored water and nutrition. The vegetation prevents water loss through evaporation. Even when the water dries up and the vegetation dies off, it is still protecting the soil underneath it.
One of the most important benefits of wetlands is that they act as filter, cleaning the water of pollutants such as sediment, excess nutrients like nitrogen and phosphorus, heavy metals, disease-causing bacteria and viruses. They help to neutralise synthesised organic pollutants such as pesticides.
Wetlands also prevent soil erosion through binding and stabilising the soil.
Threats to our wetlands
According to the Dept of Environment, 48% of our wetland ecosystem types are critically endangered. South Africa has lost approximately 50% of the original wetland area. Threats include:
- Invasive alien plants;
- Erosion;
- Developments within and around wetlands;
- Draining of wetlands;
- Pollution and excess nutrients;
- Burning of wetlands;
- Mining.
Featured image: Blesbokspruit Wetland, Gauteng Tourism
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