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Scientific Name | Sorocephalus tenuifolius R.Br. |
Higher Classification | Dicotyledons |
Family | PROTEACEAE |
Common Names | Diminutive Clusterhead (e) |
National Status |
Status and Criteria | Endangered B1ab(iii,v)+2ab(iii,v) |
Assessment Date | 2019/01/30 |
Assessor(s) | A.G. Rebelo, D. Raimondo & L. von Staden |
Justification | Sorocephalus tenuifolius is a restricted range species with an extent of occurrence (EOO) of 25 km², and an area of occupancy (AOO) of 24 km². It is known from three locations and the population is declining as a result of alien plant invasion and too frequent fires. It has lost habitat in the past to fruit orchard cultivation, dam construction and gravel mining. It therefore qualifies for listing as Endangered under criterion B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species is endemic to the Western Cape Province of South Africa where it occurs in the Palmiet River Mountains between Grabouw and the Kogelberg. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Kogelberg Sandstone Fynbos |
Description | It grows on moist sandy slopes and flats. Mature individuals are killed by fires, and only seeds survive. Seeds are released after ripening, and dispersed by ants to their underground nests, where they are protected from predation and fire. It is pollinated by insects. The plants favour natural washaways, and erosion scarps, where there are few other plants, seldom occurring in normal Fynbos, although it does sometimes occur in sparse Fynbos. This initially confused ecologists, who considered its habitat as degraded. However, it seems unable to establish in normal vegetation, and only occurs in naturally denuded areas where other plants do not occur. |
Threats |
| At least 24% of the habitat has been lost in the past due to orchard planting, gravel mining and dam construction. There are ongoing too frequent fires that are preventing the plants from setting seeds. It is also threatened by competition from invasive alien hakeas and pines. |
Population |
This species is known from four subpopulations. One subpopulation used to occur at Somersfontein where there were 700 plants in 1980, this subpopulation was destroyed by ploughing in 1983. One of the three remaining subpopulations occur at Arieskraal where there were about 50 plants in a 100 m² area in 1996 and 2013. A second extant subpopulation occurs just outside of the town of Grabouw where there are 60 plants in natural vegetation close to the Kogelberg Dam. The last subpopulation occurs within the Kogelberg Nature reserve where around 2000 plants occur over a 3.6 km area on the south banks of the Palmiet River. Monitoring of this subpopulation since 1995 has showed that numbers fluctuate depending on fire conditions. It appears that the erosion of its habitat is accelerating. The colony appears to have shifted with the densest portions moving from the erosion scars of the previous fire to sparse Fynbos vegetation during this cycle. Overall there is suspected to be a slow decline of the population as a result of habitat degradation.
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Population trend | Decreasing |
Conservation |
| The largest of the three extant subpopulations occurs in the Kogelberg Nature Reserve. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Sorocephalus tenuifolius R.Br. | EN B1ab(ii,iii,v)c(iv)+2ab(ii,iii,v)c(iv) | Raimondo et al. (2009) | | Sorocephalus tenuifolius R.Br. | Endangered | Hilton-Taylor (1996) | | Sorocephalus tenuifolius R.Br. | Endangered | Hall et al. (1980) | |
Bibliography |
Goldblatt, P. and Manning, J.C. 2000. Cape Plants: A conspectus of the Cape Flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.
Hall, A.V., De Winter, M., De Winter, B. and Van Oosterhout, S.A.M. 1980. Threatened plants of southern Africa. South African National Scienctific Programmes Report 45. CSIR, Pretoria.
Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.
Manning, J.C. and Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: The Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.
Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
Rebelo, T. 2001. Sasol Proteas: A field guide to the proteas of southern Africa. (2nd ed.). Fernwood Press, Vlaeberg, Cape Town.
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Citation |
| Rebelo, A.G., Raimondo, D. & von Staden, L. 2019. Sorocephalus tenuifolius R.Br. National Assessment: Red List of South African Plants version . Accessed on 2025/05/14 |
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