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Location South Africa, Northern Cape
Central coordinates 16o 28.00' East  28o 36.00' South
IBA criteria A1, A3, A4i, A4iii
Area 9,600 ha
Altitude 0 - 10m
Year of IBA assessment 2001

BirdLife South Africa



Site description The Orange river mouth is located on the arid Atlantic coast at South Africa’s border with Namibia. The nearest towns are Alexander Bay in South Africa and Oranjemund in Namibia. This site is a 13 km long section of the Orange river, including its flood-plain and terrestrial matrix, running from the ocean to Pachtvlei, just east of the Sir Ernest Oppenheimer Bridge. The delta-type river mouth consists of a series of braided troughs interspersed with sandbanks, channel bars and small islands, with a tidal basin and a saltmarsh on the south bank. The Orange river drains the largest catchment in South Africa, with an area of 549,700 km² and a mean annual run-off of 12,000 million cubic metres.

The major vegetation-types include islands dominated by Scirpus, Phragmites and Sporobolus. The peripheral marshes are dominated by various herbs, sedges and grasses. The upper flood-plain vegetation consists primarily of Lycium, Tamarix and Juncus, which gradually give way to terrestrial vegetation. On the lower flood-plain the soils have a high salinity as a result of evaporation and the peripheral marshland is dominated by salt-tolerant Sarcocornia.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
South African Shelduck Tadorna cana winter  350-854 individuals  A4i  Least Concern 
Cape Shoveler Anas smithii winter  162-353 individuals  A4i  Least Concern 
Black-necked Grebe Podiceps nigricollis winter  344-1,022 individuals  A4i  Least Concern 
Cape Cormorant Phalacrocorax capensis resident  831-5,000 breeding pairs  A1, A4i  Endangered 
Cape Cormorant Phalacrocorax capensis winter  7,500-10,000 individuals  A1, A4i  Endangered 
Ludwig's Bustard Neotis ludwigii resident  1998  present  A3  Endangered 
Pied Avocet Recurvirostra avosetta non-breeding  402-588 individuals  A4i  Least Concern 
Kelp Gull Larus dominicanus breeding  85-150 breeding pairs  A4i  Least Concern 
Kelp Gull Larus dominicanus winter  1,036-1,676 individuals  A4i  Least Concern 
King Gull Larus hartlaubii winter  1,152-2,511 individuals  A4i  Least Concern 
Common Tern Sterna hirundo winter  10,000 individuals  A4i  Least Concern 
Damara Tern Sterna balaenarum breeding  common  A1  Near Threatened 
Cape Long-billed Lark Certhilauda curvirostris resident  1998  present  A3  Least Concern 
Barlow's Lark Certhilauda barlowi resident  1998  present  A3  Least Concern 
Pale-winged Starling Onychognathus nabouroup resident  1998  present  A3  Least Concern 
Tractrac Chat Cercomela tractrac resident  1998  present  A3  Least Concern 
A4iii Species group - waterbirds winter  20,000-49,999 individuals  unknown  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Orange River Mouth Wetlands of International Importance (Ramsar) 2,000 protected area contained by site 2,000  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Salt marshes  -
Grassland Grassland - edaphic, wet  -

Land use

Land-use Extent (% of site)
water management 40%
nature conservation and research 100%
tourism/recreation -

Other biodiversity The system holds several endemic and threatened fish species, including Barbus hospes (LR/nt) and Austroglanis sclateri (DD). Several endemic and localized amphibians and reptiles occur in the terrestrial vegetation surrounding the estuary, and consideration should be given to securing a conservation area including the terrestrial matrix. Three highly range-restricted endemic frogs, Cacosternum namaquense, Breviceps macrops and B. namaquensis occur in the dunes and rocky outcrops adjacent to the mouth, particularly in the Alexkor restricted mining area to the south. Endemic mammals in the surrounding habitat matrix include Bathyergus janetta (LR/nt).

References Allan and Jenkins (1993), Brooke et al. (1982), Brown (1959), Cooper and Hockey (1981), Cooper et al. (1982), Courtenay-Latimer (1963), Cowan (1995), Cowan and Marneweck (1996), Day (1981), Frost and Johnson (1977), Grindley (1959), Manry (1978), Morant and O’Callaghan (1990), Noli-Peard and Williams (1991), Plowes (1943), Roberts (1989), Ryan and Bloomer (in press), Ryan and Cooper (1985), Ryan et al. (1998), Swart et al. (1988), van Zyl (1991), Whitelaw et al. (1978), Williams (1986).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Orange River Mouth Wetlands. Downloaded from http://www.birdlife.org on 23/07/2014

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