Current view: Text account
Site description (2001 baseline):
Site location and context
The Cunene river, like the Orange river, forms an east–west linear oasis of permanent freshwater across the northern Namib desert before reaching the Atlantic Ocean. It is a warm-water river, with highly variable annual flow volumes differing as much as 14-fold between and high and low years. It also varies within years by as much as 11-fold between high flow in April and low flow in October. The lower Cunene is the 340 km stretch of river that forms the border between Namibia and Angola. The mouth is considered to be the lower part of the river within 4 km of the coast. Flow to the sea is never closed off, even though it may naturally slow to a trickle in September–October. Epupa Falls, about 190 km upstream, is the last major waterfall along this very steep river that flows for 1,050 km from source (in the Angolan highlands) to mouth. It also marks the proposed site for a hydroelectric dam, which would produce a body of water c.75 km in length. At present hydro-power in Namibia is only generated from the diversion weir located at Ruacana, the end point of this IBA. Either side of the river, rocky cliffs, wind-stripped plains and dune-fields mark its progress through the hyper-arid desert. The river is typically confined to rocky gorges for most of its 340 km journey along the border of Angola.
Riparian and marginal (mainly
Phragmites) vegetation is confined to narrow strips along the riverbank. Where the river widens and braids into several channels, or mist generated from waterfalls creates a relatively humid environment, riverine vegetation occurs in profusion.
Hyphaene palms are common and luxuriant at Epupa, attracting peripheral species found nowhere else in Namibia. On surrounding hillsides, mopane and
Commiphora dominate. Nomadic pastoralists, the Ova-Himba, descendants of the Herero, number about 5,000, and are reliant on the river for water in the dry season. Extremely high temperatures (more than 40°C) are common here, and the river’s effect as an oasis in a hostile environment then becomes most apparent.
See Box and Tables 2 and 3 for key species. The river and surrounding areas support over 300 bird species. River surveys have revealed c.92 wetland birds/10 km of river (comprising mainly herons), with more birds and species occurring in the western reaches. Where dense ribbons of palms fringe the river, birds occur at much higher densities (132 birds/10 km) than areas without palms (34 birds/10 km). The riparian fringe is home to two highly localized species found nowhere else in southern Africa. These are
Cichladusa ruficauda and the near-threatened
Estrilda thomensis. Both are associated with
Hyphaene palms and adjacent riverine thickets. Several species have isolated populations here, hundreds of kilometres from their stronghold in the Okavango and adjacent wetlands. These include
Turdoides hartlaubii,
Lagonosticta rhodopareia,
Ploceus xanthops,
Malaconotus blanchoti and
Ceyx pictus. A distinctive race of
Francolinus afer also appears here, with the closest other southern African records being in eastern Zimbabwe. These species co-occur with near-endemics such as
Turdoides gymnogenys,
Namibornis herero,
Poicephalus rueppellii and
Lanioturdus torquatus.
Non-bird biodiversity: Five species of fish are endemic to the river, of which a newly discovered (1997) species may become extinct if the proposed dam development goes ahead, since it breeds in shallow water on flooded banks. A snake new to science, Coluber zebrinus, was recently discovered here. Elephants Loxodonta africana (EN) use the river as an oasis.
Pressure/threats to key biodiversity
The existence of this area is threatened by a proposal to build a hydroelectric scheme near Epupa Falls further upstream on the Cunene river. No fewer than nine dams have been proposed for the lower reaches of the river, four of them between Epupa and Ruacana, within the IBA. The first, at Epupa Falls, will be 17 times larger then Namibia’s largest existing dam, flooding 75 km of river and an area of 200 km², including most of the IBA. During the time that it takes 127>for the dam to fill and reach operational capacity (possibly four years), the resulting reduced or possibly zero water flow along the Cunene could have drastic effects on the river and its riparian vegetation. If the Epupa site (still optional) is chosen, the dam waters will inundate the primary area holding most of the national populations of
Estrilda thomensis and
Cichladusa ruficauda. Owing to annual draw-down, it is expected that none of the riverine vegetation would re-establish, effectively eliminating the most species-rich areas associated with the palm fringe. A dam at Baynes, the alternative site, would have a reduced impact owing to lower species-richness and fewer palms. The effect of the Ruacana diversion weir has been to create fluctuations in water-levels of 20–110 cm (depending on river width) within a 24-hour period. Fish reliant on flooding of levees have been severely affected and may eventually become extinct if these short-term fluctuations persist.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Epupa - Ruacana (Namibia). Downloaded from
https://datazone.birdlife.org/site/factsheet/epupa--ruacana-iba-namibia on 27/12/2024.
