Botswana: Is Okavango Delta Shrinking?

Mmegi/The Reporter (Gaborone)
May 5, 2006
Monkagedi Gaotlhobogwe

An international NGO, BirdLife has stirred controversy with recent findings that the Okavango Delta - the main water source of regional wildlife in long dry seasons, and the main bird-breeding site in inland Southern Africa - shrunk by almost half in the last ten years.

Birdife says the last ten years were exceptionally dry. Ministry of Environment, Wildlife and Tourism's National Conservation Strategy based in Maun have refuted the findings dismissing them as misguided. In their research conducted in 2005, Birdlife Botswana teamed up with the Department of Wildlife and National Parks to conduct the one-year survey that was loaded onto Birdlife's website on May 2. The survey further says Southern Africa has experienced a decade of drought, which many climate researchers perceive as an omen of a drier climate in the future on the sub-continent due to the worldwide process of global warming. The survey found that the Delta has reduced in size, and it attributes the changes to long-term climate fluctuations.

According to the Botswana Birdlife report, the wetland area is currently just over half its maximum size of 20,000 square kilometres. The actual size of the delta is estimated to be 55,000 km2, making the Okavango the world's largest wetlan ds. The report says the unique inland delta is slowly changing due to a drier climate, increased grazing and growing pressure from tourism. Also, direct human activity is blamed for the shrinking of the delta because people have now infringed on the valuable wetland area, mostly with the desire to take advantage of the tourism boom that brings thousands of tourists from all over the world to Ngamiland to experience the wonders of the Okavango. As a result of the environmental changes taking place at the Okavango, the report says, vulnerable birds like the slaty egret, found most plentifully in the area are now in danger of extinction. However, Maun-based project facilitator at the Okavango Delta Management Plan (ODMP) - a division of the department of the National Conservation Strategy in the Ministry of Environment, Wildlife and Tourism - does not agree with the survey finding.

The facilitator, Comfort Molosiwa, says the survey was based on the rare bird, Mmamoleane, or the slaty egret, which is found mostly at the delta. Molosiwa says it would be misleading to say that the delta has shrunk by almost half over the last decade will be misleading. He says the researchers got it wrong when they said that the Okavango delta is 55,000 square kilometres in size. Molosiwa says the 55 000 square kilometres area is the 'ramsar' site or the study area, which also includes dry land. He told Mmegi that the wetland has always consisted of almost half of the ramsar area and that to say the dry land used to be part of the wetland was not correct. Molosiwa told Mmegi that water levels at the delta may fluctuate from time to time depending on the amounts of rains received from Angola or Namibia, where the river that empties into the delta originates. He said the statement by both Birdlife Botswana and its mother body needs to be seen against other facts as it might give the wrong picture. Molosiwa says that he will soon release a detailed report to correct thi s error as he believes the international community has been misled.

Molosiwa says his division is responsible for, among others, coming up with integrated hydrological models for the delta in order to establish the water balance of the Okavango. He said the model would be used as a management tool to determine the impact of any uptake from the delta that may result from such activities as the blockage of the streams, or developments along the river such as irrigation or dams. Molosiwa said his office is also responsible for reviving blocked channels that may reduce the inflow. Molosiwa also told Mmegi that as far as he is aware, only a draft report has been concluded. He said he is making his own contribution to the draft report and wondered how a draft report could be publicised before it was finalised. Birdlife Botswana was not available for comment on the telephone by Thursday. During the study, BirdLife Botswana was interested particularly in the slaty egret (Egretta vin aceigula), known in Setswana as Mmamoleane, a vulnerable water bird living only in Southern Africa.

The egret, which has its main breeding grounds in the wetlands of Zambia, Mozambique and Botswana's Okavango Delta, has an estimated population of 4,000. The survey team managed to collect "valuable data on the ecology" of the egret, according to Pete Hancock of BirdLife Botswana. After the survey, it was found that the bird no longer have a breeding place on the delta because their breeding places - the reed beds and water fig islands - have been destroyed. Earlier studies found egret nests in the Okavango Delta, typically in the reed beds and water fig islands that have now been destroyed. No egret breeding sites were found during the survey. The survey concluded that the egret, which was already registered on the IUCN's red list of threatened species as "vulnerable", seems to be losing one of its main breeding sites - the Okavango. Several factors threaten the egret, BirdLi fe noted, "notably increased accessibility and disturbance to reed beds by cutters and tourists, loss of some feeding areas, destruction of habitat by fire and the increased use of reed beds by large mammals, especially elephants". The Okavango Delta is regarded as one of the great wonders of the world. With its diversity of wildlife and plants, as well as amazing large body of water in a desert environment, the Okavango delta is simply a wonder to behold. Each year, after the rainy season, the delta floods, and animals from across the savannah flock there to mate and raise their young ones alongside its plentiful banks. Antelope, zebra, lion, hyena, buffalo, leopard, cheetah, giraffe, elephant as well as hundreds of bird species are just some of the eye-catching features of the Okavango. This entire splendour is under threat.

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