Orange River Estuary - Southern Namib Desert (100936)
South Africa, Africa
Site overview
KBA status: confirmed
Global KBA criteria: A1a, A1c, A1e, A2, B1, B2, B3a, B4, E
Year of last assessment: 2024
National site name: Orange River Estuary - Southern Namib Desert
Central coordinates: Latitude: -28.4397, Longitude: 16.7651
System: terrestrial, marine, freshwater
Elevation (m): 0 to 826
Area of KBA (km2): 871.63411
Protected area coverage (%): 6.03
KBA classification: Global
Legacy site: No
Site details
Site description: Orange River Estuary - Southern Namib Desert is a terrestrial site that has limited protection but has OECM coverage, found in the Northern Cape, South Africa. Heterogeneous broken landscape in the extreme north west of the country. Mostly hilly but including some plains South of the Orange River and the large fluvially dominated Orange River estuary (which form the border between South Africa and Namibia). Some of the plains are covered by quartz gravel, others by loamy sand or by gravel from different rocks, with strong contrasts between different mosaic elements. The main vegetation unit includes quartz fields, which are covered by dwarf cushions of the Brownanthus pubescens community and the Hartmanthus pergamentaceus community. The undulating hills, especially on southwestern slopes, are covered by the Ruschianthemum gigas desert shrubland community, while rocky outcrops sometimes support populations of the spectacular Aloe pillansii. On rocky hilly landscapes, sparse low shrubland with mainly leaf and stem succulent chamaephytes predominates. The vegetation of vast areas is heavily degraded and invaded by the annuals. Most of the open plains of this unit are seemingly bare of any vegetation, with the exception of scattered individuals of Sarcocaulon patersonii or very sparse grasslands of Stipagrostis geminifolia. A closer look reveals quite a number of species sunken into or even (for well-defined periods of time) underneath the soil surface (subterrestrial chamaephytes, e.g. Fenestraria rhopalophylla).
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for 3 criteria described in the Global Standard for the Identification of KBAs. Based on current available information, 17 species meet one or more KBA criteria for this site. The KBA trigger species at this site include birds, plants, and reptiles. The site meets criterion A1 due to the presence of significant proportions of the global populations of 7 threatened species. Effectively the entire global population of one Endangered species is within the site. The site regularly holds 9 individual geographically restricted species, therefore meeting criterion B1. An assemblage of co-occurring range-restricted species in the Caryophyllales taxonomic group regularly present within the site meets criterion B2. A quantitative analysis of irreplaceability indicates that the site is 100% irreplaceable for the global persistence of 8 species, therefore meeting criterion E. The site holds significant proportions of the global extent of 2 threatened ecosystems (meeting criterion A2).
Additional biodiversity: 47 other potential trigger species meet minimum population parameter thresholds for the site, but presence and/or minimum reproductive units required to meet KBA criteria cannot be confirmed with available data.
Manageability of the site: This site is managed primarily by a regional conservation authority responsible for enforcing statutory regulations on landuse change in Critical Biodiversity Areas and threatened ecosystems, with part of the site managed by a protected area management authority.
Supersedes another site: Orange River Mouth Wetlands ZA023 [3%]
Delineation rationale: Expanded estuarine Important Bird and Biodiversity Area including small protected area and adjacent desert landscape, categorised as Critical Biodiversity Area. Site adjoins large KBA and World Heritage Site / protected area to the east and the Namibia - South Africa border to the north.
Habitats
Summary of habitats in KBA: Desert (75%), Shrubland (14%), Artificial - terrestrial (8%)
Threats
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Residential & commercial development | Commercial & industrial areas | Ongoing | |
| Energy production & mining | Mining & quarrying | Ongoing | |
| Natural system modifications | Dams & water management/use | Ongoing |
Additional information
Contributors: Gavin Masterson (Fathom Data), Warrick Stewart (Resilience Environmental Advice), Anisha Dayaram (South African National Biodiversity Institute), Maphale Monyeki (South African National Biodiversity Institute), Sediqa Khatieb (South African National Biodiversity Institute), Craig Hilton-Taylor (IUCN)