Current view: Text account
Site description (2001 baseline):
Site location and context
Located in the eastern Caprivi bulge, this wetland system lies on Namibia’s international border with Botswana, Zambia and Zimbabwe, and stretches from the Kwando river in the west, to the Zimbabwean border-post at Kazungula in the east. It is Namibia’s largest single permanent wetland and is fed by two of the country’s five perennial rivers. The area is divided into five geographically distinct zones: the Upper Kwando (137 km²), Lower Kwando and Linyanti Swamp (3,830 km²), the ephemeral Lake Liambezi (406 km²), the Chobe river and marsh (311 km²) and the Zambezi flood-plains (1,800 km²).
The area is topographically featureless and almost completely flat—a key determinant in the unusual hydrological regime. Under flood conditions, the Kwando is essentially linked to the Zambezi, with water flowing from the Kwando into the Linyanti Swamp, about 10% of which finally reaches Lake Liambezi. This water is, however, insufficient to keep the lake level from dropping. When full, Lake Liambezi has an outlet to the Chobe river, which subsequently joins the Zambezi at Kazungula. When the Zambezi is in flood, the flow is reversed and water is pushed up the Chobe to Liambezi. Lake Liambezi and the flood-plain zone are thus only intermittently inundated, while the Zambezi, Kwando, Linyanti Swamp and Chobe Marsh are permanent features. The abrupt change in the direction of the Kwando river as it merges into the Linyanti system is due to the extensive geological faulting present in the area. Floodwaters channel down the Kwando between June and August and then swing north-east along the Chobe fault into the Linyanti Swamp. It may take up to six months for water to percolate through the
Phragmites/
Cyperus dominated reed-swamp, as less than one third of the area is open water. By 1997 Lake Liambezi was a dry lakebed, completely overgrown and partly farmed; these long-term dry/wet periods appear to be cyclical.
The Chobe Marsh, into which the Linyanti Swamp and Lake Liambezi drain when full, is more usually inundated by water backing up along the Chobe from the Zambezi river. The Zambezi floods typically last 4–6 weeks in March–April, before subsiding back into side channels and the main Chobe/Zambezi channels. However, the lower-lying flood-plains remain inundated for longer periods, and support vast beds of papyrus and reed in a maze of small channels and islands. The climate of the region can be divided into two distinct seasons—a dry season between April and November, and a shorter wet season which stretches from the end of November to late March/early April. This is the wettest place in Namibia with rainfall averaging 740 mm per year, and sometimes exceeding 1,000 mm per year. The monthly average maximum temperature is about 30°C.
The area is surrounded by pristine riparian fringes, which are extremely rare in Namibia, as they have mostly been destroyed by human activity. The vegetation is dominated by trees of
Lonchocarpus,
Garcinia,
Syzygium and
Diospyros. The flood-plain consists of reedbeds, swamps, open flooded grasslands and papyrus. Two conspicuous species on the edge of the flood-plain are the wild date-palm
Phoenix and baobab
Adansonia.
See Box and Table 3 for key species. East Caprivi as a whole, and its wetlands in particular, holds one of the richest diversities of bird species anywhere in Namibia. The high diversity arises from a combination of wetland and tropical (passerine) species extending into this region. The most important features of this system are the swampy areas and flood-plains, which are important breeding habitat for wetland birds. These and other wetland species include
Egretta vinaceigula,
Grus carunculatus,
Ardeola rufiventris,
Ephippiorhynchus senegalensis,
Microparra capensis,
Vanellus albiceps,
V. crassirostris,
Glareola pratincola,
Macronyx ameliae and
Circus pygargus.
Non-bird biodiversity: Threatened mammals occurring here include Lycaon pictus (EN) and thousands of Loxodonta africana (EN).
Pressure/threats to key biodiversity
Until recently, there were no conservation areas in existence in East Caprivi. On 1 March 1990, two conservation areas were proclaimed. One, the wetland Mamili National Park (32,000 ha), which is centred on Nkasa and Lupala Islands near the Linyanti Swamp in the south-western corner of East Caprivi. The surface area of water fluctuates, but at high floods some 80% of the area is inundated. This area provides essential protection for many swamp and flood-plain species. The other 127> protected area, Mudumu National Park (101,400 ha) is mainly woodland, with small areas of wetland on the western fringes where it borders the Kwando river. In dry years it is possible that these parks will be the only areas in East Caprivi that are not overgrazed.
The two parks will, however, only be effective at maintaining the region’s biodiversity if legislation and enforcement are improved, and wildlife education and communication programmes for the surrounding rural communities are continued. Involvement of local communities in the management of buffer zones and running of tourist camps has helped to alleviate current encroachment into these parks. The region’s waterways have held the alien water-fern
Salvinia since the 1950s. This weed has caused massive problems by clogging waterways and altering the functioning of the wetlands, and locally threatening other macrophytes with extinction. Currently the
Salvinia infestation is under control owing to a successful biological-control programme initiated in 1981. The distribution of the weed has not changed, but the intensity of the infestation has been reduced and in some places is almost eradicated.
Organized poaching for ivory and hunting for meat are thought to be responsible for the demise of the herbivores that once teemed in this region. Uncontrolled army poaching during the guerrilla war also took its toll on wildlife. Campaigns by various government and non-government organizations have temporarily solved the problem; stocks are, however, drastically depleted and require a period to recover before sustainable harvesting can be implemented. Spraying of dieldrin and DDT to control tsetse fly
Glossina and malaria has been widespread in the past and occasionally still occurs. Monitoring programmes investigating toxicity levels in the resident human population and other non-target tertiary consumers are essential as these organisms could accumulate toxins.
The other greatest threat to the area is the grazing pressure exerted by a burgeoning population of over 100,000 head of cattle, 60% of which are estimated to be concentrated on the eastern flood-plain (30% of the area). With the drying out of Lake Liambezi, local inhabitants intensively fish the Chobe river with mosquito nets. This unsustainable level and unselective method of fishing may have detrimental consequences on the recovery of fish populations once floods return. Human disturbance to
Rynchops flavirostris from waves caused by motorized boats destroys nesting sites. Disturbance causes adult birds to abandon their nests, exposing eggs and chicks to intolerable heat and additional predation pressure.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Eastern Caprivi wetlands (Namibia). Downloaded from
https://datazone.birdlife.org/site/factsheet/eastern-caprivi-wetlands-iba-namibia on 22/11/2024.
