email a friend
printable version
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



Summary The Orange River mouth is located on the arid Atlantic coast at South Africa's border with Namibia. This IBA is a 13 km long section of the Orange River, including its floodplain and terrestrial matrix. Bird numbers and diversity can be as high as 26 000 individuals comprising 56 species.

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.

Key Biodiversity See Box and Table 3 for key species. The Orange river mouth is considered to be the sixth most important coastal wetland in southern Africa in terms of the overall number of wetland birds that it supports, which can be as high as 26,000 individuals, from a total of 56 such species recorded. Numbers drop off considerably in winter, suggesting that the large majority of the birds are migratory or indulge in local movements. The Orange river mouth is used by birds primarily for breeding or as a stop-over on migration. At times the area supports more than 1% of the world populations of Phalacrocorax capensis, Tadorna cana, Anas smithii and Larus hartlaubii. The wetland and adjacent coastal dunes also support substantial numbers of Sterna balaenarum. Substantial proportions of the southern African populations of Podiceps nigricollis, Oxyura maccoa, Charadrius pallidus, Sterna bergii, and Sterna caspia are periodically supported at the Orange river mouth. Circus ranivorus occur along marshy sections of the riverbank and in the surrounding lucerne fields. The mouth supports a few resident Haematopus moquini and, in summer, large numbers of migrant Palearctic waders.

Near Pachtvlei, the terrestrial vegetation surrounding the wetland supports Francolinus capensis, Cercomela tractrac and two recently recognized larks, Certhilauda barlowi and C. curvirostris. The latter two species have restricted ranges (covering less than 50,000 km² each) that overlap, indicating that the Secondary Area of avian endemism recognized in this part of the Karoo (the restricted-range species Certhilauda burra occurs at three nearby IBAs: 025, 026, 027) should be upgraded to the status of Endemic Bird Area (EBA) when the global EBA classification is next revised.

Non-bird 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).

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 Spatula 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 
Hartlaub's 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 Sternula balaenarum breeding  common  A1  Near Threatened 
Certhilauda curvirostris resident  1998  present  A3  Not Recognised 
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   

IBA Monitoring

2014 very high very unfavourable low
Habitat
Medium - based upon reliable but incomplete / partially representative data

Agriculture and aquaculture livestock farming and ranching (includes forest grazing) - small-holder grazing, ranching or farming happening now majority/most of area/population (50-90%) slow but significant deterioration high
Biological resource use fishing & harvesting aquatic resources - intentional use: lg scale happening now some of area/population (10-49%) slow but significant deterioration medium
Biological resource use fishing & harvesting aquatic resources - intentional use: subsistence/sml scale happening now some of area/population (10-49%) no or imperceptible deterioration low
Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) happening now majority/most of area/population (50-90%) slow but significant deterioration high
Climate change and severe weather drought likely in short term (within 4 years) whole area/population (>90%) slow but significant deterioration high
Climate change and severe weather habitat shifting and alteration likely in long term (beyond 4 years) whole area/population (>90%) very rapid to severe deterioration high
Climate change and severe weather storms and floods likely in long term (beyond 4 years) whole area/population (>90%) very rapid to severe deterioration high
Climate change and severe weather temperature extremes likely in short term (within 4 years) whole area/population (>90%) slow but significant deterioration high
Energy production and mining mining and quarrying happening now some of area/population (10-49%) slow but significant deterioration medium
Human intrusions and disturbance recreational activities happening now some of area/population (10-49%) moderate to rapid deterioration high
Invasive & other problematic species, genes & diseases invasive non-native/alien species/diseases - named species happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Invasive & other problematic species, genes & diseases problematic native species/diseases - named species happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications dams & water management/use - abstraction of surface water (commercial use) happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications dams & water management/use - large dams happening now whole area/population (>90%) moderate to rapid deterioration very high
Natural system modifications other ecosystem modifications happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Pollution agricultural & forestry effluents - nutrient loads happening now majority/most of area/population (50-90%) slow but significant deterioration high
Pollution air-borne pollutants - type unknown/unrecorded happening now some of area/population (10-49%) slow but significant deterioration medium
Transportation and service corridors flight paths happening now some of area/population (10-49%) slow but significant deterioration medium
Transportation and service corridors utility & service lines happening now small area/few individuals (<10%) no or imperceptible deterioration low

Desert Coastal desert  0 0 very poor (< 40%) poor (40-69%) very unfavourable
Wetlands (inland) Estuarine waters  0 0 good (> 90%) moderate (70-90%) near favourable
Wetlands (inland) Intertidal mud, sand or salt flats  0 0 good (> 90%) moderate (70-90%) near favourable
Wetlands (inland) Salt marshes  0 0 good (> 90%) moderate (70-90%) near favourable

Little/none of site covered (<10%)  A management plan exists but it is out of date or not comprehensive  Some limited conservation initiatives are in place  low 

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) Estuarine waters; Intertidal mud, sand or salt flats; Salt marshes  -
Grassland Grassland - edaphic, wet  -
Desert Coastal desert  -

Land use

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

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).

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2015) Important Bird Areas factsheet: Orange River Mouth Wetlands. Downloaded from http://www.birdlife.org on 01/09/2015

To provide new information to update this factsheet or to correct any errors, please email BirdLife