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WETLANDS

An area that is relatively flat that aids in slowing down water movement and which has temporally seasonal, or permanently saturated soils, can be classified as a wetland.

Estuaries

Where rivers meet these, unique environments, called estuaries, are formed. These estuaries are constantly altered due to tidal action, floods, temperature variation and (depending on the system) periodic closure of the river mouth. This results in a variation of salinity (within Estuaries) due to the mixing of sea water with fresh river water.

Touws River mouth at Wilderness and Groot River mouth at Nature’s valley are examples of estuaries.

Saltmarshes

Saltmarshes are found on the landward side of mud and sand flats in the upper tidal zone of calm coastal waters, such as sheltered bays, river mouths and Estuaries.

Saltmarshes are formed on the perimeter of certain Estuaries and lagoons. The plant found here have to withstand salinities of up to 3 times that of seawater. This results in a low species diversity in saltmarshes.

Saltmarshes are characterized by a zonal distribution of groups of plants with varying tolerances to different environmental factors.

Knysna and Langebaan Lagoons are two well know examples of saltmarshes.

Why are wetlands so important?

With and influx of nutrients from both the river and sea, sea estuaries highly productive systems that form the habitat of a diverse number of flora and fauna.

Their functioning as nursery sites are of particular importance to many aquatic species (see fish section).
Plants that are adapted to wetland conditions act as sponges, helping to slow down flow and reducing the effects of floods.

Water is released slower from these areas, which means it will be available or longer. Less water is lost through evaporation due to the cover provided by wetland vegetation. They act as natural filters that help to purify the water by trapping silt, pollutants, excess nutrients, heavy metals and pesticides.

What can we do?

We all benefit from healthy wetlands directly or indirectly. By understanding and appreciating the functioning of the system one is able to, through sensible and simple practices, help protect our remaining wetlands.

• Influence those around you with your acquired knowledge of wetlands.
• Celebrate World Wetlands day on 2 February each year by organising an alien plant hack, water quality testing or bird watching.
• Stop damaging activities - illegal dumping or pollution spills - higher up the catchment which manifest themselves in the lower parts.
• Do not disturb wetlands or overfish. This causes important species numbers to dwindle.

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