The Biodiversity of Monavale Vlei
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What is biodiversity?
Biological diversity can be described as the infinite variety of living organisms: plants, animals, insects, fungi, and so on. These diverse organisms are supported by different habitats and together they form ecological systems which are also numerous and varied. The vleis of Harare are a continuous wetland ecological system with Monavale Vlei being a pristine part of this system.
Brief background of Monavale Vlei
Since 2001, The Conservation Society of Monavale Trust, COSMO, and Monavale residents have been working strenuously to protect Monavale Vlei, together with BirdLife Zimbabwe, non government organizations, national and local government authorities. COSMO continues to influence national and local government authorities to protect all the remaining wetlands and open spaces of Harare. Greater Harare is built in its water catchment basin and this severely restricts its water supply due to the impact on the wetlands from development, urban agriculture and pollution.
Only by preserving our city's wetlands and open spaces, will we be able to enhance our water supply, which is now inadequate, and safeguard against our own and our children's survival.
Monavale Vlei's wetland biodiversity
Monavale Vlei is an intact remnant of Harare's much threatened seasonally inundated grassland / wetland ecosystem. Without these spongy, water retaining and filtering open spaces, there can be no streams, rivers, dams and other wetland areas, in other words, no wetlands, no water.
These vleis are amongst the most biodiverse areas on Earth, and Monavale Vlei is especially rich in grasses, sedges, forbs, riverine vegetation, as well as mammals, amphibians, birds, reptiles, crustaceans, insects and other organisms which are adapted to this habitat. Monavale Vlei is known worldwide in ornithological circles as an important site for the secretive migrant Crakes and Rails to breed. These birds are they are dependent upon the seasonal inundation of these vleis and the fine open grasses to provide the correct breeding habitat. They are an indicator of the health of the wetlands.
Trees do not naturally occur in these wet grasslands, but are found where there has been disturbance from urban agriculture, which causes loss of wetland function. Trees dry up wetlands so tree growth in these seasonally inundated grasslands should not be encouraged.
Wetlands are significant in that they provide improved water quality, habitats for fish to spawn and for wildlife, protection from high floods, they safeguard against droughts and provide for recreational and aesthetic appreciation. Plants and soils in wetlands together play a large role in purifying water by removing high levels of nitrogen and phosphorous and other toxic chemicals. Therefore in some instances wetlands and their surroundings are more economical than building more expensive treatment plants. Wetlands also act as a 'sponge' in times of high floods by soaking up the huge volumes of water that would otherwise flow off into storm drains during high rainfall. This storage facility is critical and is lost if wetlands are disturbed. Wetland store more carbon than trees do and so they mitigate the effects of climate change. If disturbed carbon is released thus contributing to the negative effects of CC.
It is therefore vital to preserve our wetlands. They offer a huge economic saving and will serve us far better if we leave them in pristine condition.