Reviving Paradise: Why wetlands are important
Wetlands act as catchment areas for soil, sediment and nutrients.
February 2 was World Wetlands Day. We often hear about wetlands when it comes to biodiversity, but to most of us they just look like wastelands, not valuable from a property or contractors’ point of view, and just another place where waste seems to accumulate. So why are wetlands important?
Wetlands make up around 2.4% of South Africa and there are more than 300,000 wetlands across the country, categorized into 791 different types. Despite these large numbers, South Africa has lost more than 50% of its original wetlands and over 48% of the remaining wetlands are critically endangered.
Wetlands are the transition zone between terrestrial ecosystems and aquatic ecosystems. Here the water table is close to the surface and the soil is saturated with water, supporting a wide variety of aquatic and terrestrial plants. These conditions create one of the most productive ecosystems in the world.
Wetlands act as catchment areas for soil, sediment and nutrients. The plant roots create a biodynamic sponge that helps purify and filter water, adding nutrients and removing inorganic matter as well as poisons like runoff from agriculture, human effluent and even chemicals. Because they are so absorbent, wetlands store water, adding water to the flow of rivers and securing food production during dry months. They also help to hold soil back, preventing soil erosion, assisting in flood control and reducing siltation. Wetlands act as fish nurseries and help with groundwater recharge.
The Mzimkhulu River plays an important role on the South Coast, as it is the source of our drinking water. Some of the wetlands in the upper uMzimkhulu are well protected, but unfortunately some lower down have been damaged or destroyed by human activities like sand mining, agriculture and the construction of buildings, affecting the amount of water in the river and exacerbating low flow conditions during our dryer months.
Alien invasive plants also threaten wetlands, as they crowd out indigenous vegetation and make wetlands vulnerable to drying out. With climate change posing increasing risks, it is imperative that we take a more aggressive approach to protecting these critical but vulnerable ecosystems.
Pic: Farmer’s Weekly
Photo: www.rainharvest.co.za
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