Bokkeveld Escarpment (100724)
South Africa, Africa
Site overview
KBA status: confirmed
Global KBA criteria: A1a, A1b, A1c, A1d, A1e, A2, B1, B2, B3a, B4, E
Year of last assessment: 2024
National site name: Bokkeveld Escarpment
Central coordinates: Latitude: -31.4847, Longitude: 19.0881
System: terrestrial, freshwater
Elevation (m): 290 to 880
Area of KBA (km2): 1245.11658
Protected area coverage (%): 14.05
KBA classification: Global
Legacy site: No
Site details
Site description: Bokkeveld Escarpment is a large terrestrial site that has limited protection, found in the Northern Cape, South Africa. It is defined by a flat tableland, partially sloping to the east and south, without any faulting or folding in the sandstone beds. Major exposures of sandstone occur at the edge of the escarpment and where younger sediments have been removed. Topographical variability results from rivers cutting through the resistant sandstone, forming deep gorges in an otherwise flat sandstone landscape. Although the shale bands of the Cedarberg Formation are largely absent, rugged Cederberg landscape is formed on the eastern edge, where shale outcrops with flat-topped hills occur (and support outliers of Bokkeveld Sandstone Fynbos on their summits). Vegetation is mainly closed restiolands in deeper moister sands with low, sparse shrubs that become denser with decreased restioid dominance in drier areas. Restioid, proteoid and asteraceous fynbos predominate; with some waboomveld found as well. Sections with a diverse geophyte and annual community is prevalent in the wet season, and responsible for rich floral displays during spring. Dominants are strongly related to soil, displaying large compositional turnover with soil texture, depth and aspect. Progressively increasing aridity results in a more gradual transition to Hantam Karoo in the east. The vegetation of the dolerite plains is unique in being almost devoid of shrubs or perennial grasses. The koppies generally consist of cosmopolitan species derived from the adjacent karoo and renosterveld. Geophytes and annuals compose 90% of the cover and 80% of the species. In the east, dwarf Karoo shrubland with nearly equal proportions of succulent elements and low microphyllous karroid shrubs, particularly of the family Asteraceae.
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, 87 species meet one or more KBA criteria for this site. The KBA trigger species at this site include birds, butterflies, fish, plants, and reptiles. The site meets criterion A1 due to the presence of significant proportions of the global populations of 53 threatened species. Effectively the entire global populations of 8 Endangered and 2 Critically Endangered species are within the site. The site regularly holds 68 individual geographically restricted species, therefore meeting criterion B1. Assemblages of co-occurring range-restricted species in the Asparagales, Asterales, Caryophyllales, Fabales, Malvales, Oxalidales, Proteales, and Rosales taxonomic groups regularly present within the site meet criterion B2. Co-occurring species endemic to the Renosterveld shrubland terrestrial ecoregion present at the site meet criterion B3. A quantitative analysis of irreplaceability indicate that the site is 100% irreplaceable for the global persistence of 54 species, therefore meeting criterion E. The site holds significant proportions of the global extent of 1 threatened ecosystem (meeting criterion A2) and 3 geographically restricted ecosystems (meeting criterion B4).
Additional biodiversity: 140 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.
Delineation rationale: Delineation is centered around a distinctive escarpment and plateau landscape with endemic ecosystem types and species. Where possible and necessary, delineation matches the boundaries of protected areas on the escarpment.
Habitats
Summary of habitats in KBA: Shrubland (82%), Artificial - terrestrial (16%)
Threats
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops | Scale Unknown/Unrecorded | 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)