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Scientific Name | Serruria deluvialis Rourke |
Higher Classification | Dicotyledons |
Family | PROTEACEAE |
Common Names | Grass Spiderhead (e) |
National Status |
Status and Criteria | Endangered A2ce; B1ab(iii,v)+2ab(iii,v); C1 |
Assessment Date | 2020/08/05 |
Assessor(s) | A.G. Rebelo, D. Raimondo & L. von Staden |
Justification | Serruria deluvialis is a restricted endemic species to the Kogelberg Mountains of the Fynbos Biome, South Africa. It has an extent of occurrence (EOO) and an area of occupancy (AOO) of 24 km². A population reduction of at least 50% is estimated based on loss of suitable habitat to fruit orchards, dam construction and alien plant invasions in the past 60 years (generation length 20 years). There are three remaining locations and the population which consists of fewer than 1000 mature individuals continues to decline due to ongoing habitat degradation from invasive alien plant species. It therefore qualifies for listing as Endangered under criteria A, B and C. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species is restricted to the Kogelberg Mountains, in the Western Cape Province, South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Kogelberg Sandstone Fynbos |
Description | It grows on seasonally waterlogged sandstone slopes, 100-300 m. Mature individuals are killed by fires, and only seeds survive. Seeds are relased after ripening, and dispersed by ants to their underground nests, where they are protected from predation and germinate following fire. It is pollinated by insects. |
Threats |
| Over 50% of this species former habitat has been lost to agricultural development in the Elgin Valley and the building of the Kogelberg Dam. Remaining subpopulations are threatened by competition with alien invasive plants (pines, hakeas and acacias). |
Population |
Only five subpopulations of this species are known, two have gone extinct. One at Arieskraal and another at Somersfontein were ploughed up for orchards and dams in 1983. There are three remaining extant subpopulations. One small subpopulation remains on the road to Kogelberg Dam where there are fewer than 20 plants. Another small subpopulation remains on the private farm Solva where there is one patch of around 100 plants. The largest extant subpopulation occurs at Stokoe Bridge within the Kogelberg Nature Reserve where there are several hundred plants. The total population consists of fewer than 1000 plants and more than 20% of the population has been lost in the past two generations (1980-2020). The remaining population is declining due to ongoing competition with invasive alien plant species.
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Population trend | Decreasing |
Conservation |
| It is conserved in Kogelberg at Stokoe bridge. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Serruria deluvialis Rourke | EN A2c; B1ab(iii)c(iv)+2ab(iii)c(iv) | Raimondo et al. (2009) | | Serruria deluvialis Rourke | Vulnerable | Hilton-Taylor (1996) | |
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.
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. 2020. Serruria deluvialis Rourke. National Assessment: Red List of South African Plants version . Accessed on 2025/05/17 |
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