Knersvlakte (100825)
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: Knersvlakte
Central coordinates: Latitude: -31.2862, Longitude: 18.5677
System: terrestrial, freshwater
Elevation (m): 22 to 675
Area of KBA (km2): 6451.91893
Protected area coverage (%): 14.92
KBA classification: Global
Legacy site: No
Site details
Site description: Knersvlakte is a very large terrestrial site with limited protection, found in the Western Cape, South Africa. It is situated within an extensive landscape of undulating slopes and broad ridges covered by prominent though very patchy white layer of quartzite. The succulent shrublands supported by this relatively young (Tertiary) plain are mostly dwarf, with a high proportion of compact and subterranean vygies (Aizoaceae), often imitating their surroundings. The mosaic of floristically and ecologically distinct quartz vygieveld communities and the matrix of low succulent shrublands, with Ruschia and Drosanthemum as the most prominent structure-determining genera, are very intricate and small-scale in places. Spectacular flower displays of both perennial and annual species flowering en masse and simultaneously are a common sight after good winter rain. In the south, there are shale plains that can acquire a grassland appearance through seasonal dominance of Bromus pectinatus and Stipa capensis. On quartzite koppies and hills are asteraceous and leaf-succulent shrubs (0.4 to 1.5 m). The site is rich in local endemic species.
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, 114 species meet one or more KBA criteria for this site. The KBA trigger species at this site include amphibians, birds, butterflies, fish, plants, and reptiles. The site meets criterion A1 due to the presence of significant proportions of the global populations of 56 threatened species. Effectively the entire global populations of 12 Endangered and 6 Critically Endangered species are within the site. The site regularly holds 90 individual geographically restricted species, therefore meeting criterion B1. Assemblages of co-occurring range-restricted species in the Asparagales, Asterales, Caryophyllales, Geraniales, Oxalidales, and Saxifragales taxonomic groups regularly present within the site meet criterion B2. Co-occurring species endemic to the Succulent Karoo xeric shrublands terrestrial ecoregion present at the site meet criterion B3. A quantitative analysis of irreplaceability indicates that the site is 100% irreplaceable for the global persistence of 55 species, therefore meeting criterion E. The site holds significant proportions of the global extent of 1 threatened ecosystem (meeting criterion A2) and 10 geographically restricted ecosystems (meeting criterion B4).
Additional biodiversity: 248 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 protected area management authority, with part of the site managed by a regional conservation authority responsible for enforcing statutory regulations on landuse change in Critical Biodiversity Areas and threatened ecosystems.
Delineation rationale: Delineation is focused around a distinctive landscape and vegetation.
Habitats
Summary of habitats in KBA: Shrubland (94%), Artificial - terrestrial (6%)
Threats
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops | Scale Unknown/Unrecorded | Ongoing |
| Natural system modifications | Dams & water management/use | Ongoing | |
| Energy production & mining | Mining & quarrying | 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)