The conservation condition of the unprotected Okavango Delta, Botswana

[摘要] English: The Okavango River lies within the semi-arid Kalahari Desert of southern Africa and is an extremely important source of food and water. This river ends in an inland delta in Botswana which supports the livelihoods of thousands of people, some of whom rely directly on the river for survival. The Delta is one of the largest Ramsar sites in the world and is thought to be amongst the only pristine places left on earth. The eastern Delta fan is a protected area, the Moremi Reserve, whilst the Panhandle, the western Delta fan and Lake Ngami are unprotected. In the mid-eighties a limnological study of the Okavango Panhandle was undertaken by Rhodes University. Against this background the following questions were formulated: how did human activities change in the unprotected Okavango Delta during the past 23 years; how did it influence the water quality of the system and how did it affect the ecological integrity of the system, if at all? Using the limnological profile as baseline, not only were the study sites revisited and water quality measurements repeated, but samples were taken all the way from Popa Falls in Namibia to lagoons in the north-western Delta fan and at Lake Ngami. Despite the increase in human activities and livestock, physical water quality parameters lie within the ranges as set out in the Water Quality Guidelines of South Africa, while most chemical substances are below detection limit. The microbiological water quality should be studied in more detail. The Okavango Delta is a dynamic, yet fragile, ecosystem and projects such as the proposed hydroelectric plant and the Eastern National Water Carrier project may have adverse effects. Livestock and the erection of veterinary cordon fences, amongst others, have proved to be detrimental to the system.

[发布机构] University of the Free State