Peninsula Spiderhead

Taxonomy
Scientific Name
Serruria decumbens (Thunb.) R.Br.
Higher Classification
Dicotyledons
Family
PROTEACEAE
Synonyms
Serruria hyemalis Salisb. ex Knight
Common Names
Peninsula Spiderhead (e)
National Status
Status and Criteria
Endangered B1ab(iii)+2ab(iii)
Assessment Date
2020/06/03
Assessor(s)
A.G. Rebelo, D. Raimondo & L. von Staden
Justification
Serruria decumbens is a range-restricted endemic that occurs as isolated subpopulations along a 22 km range of mountains on the southern part of the Cape Peninsula in South Africa. It has an extent of occurrence (EOO) of 80 km² and an area of occupancy (AOO) of 60 km². Subpopulations at two threat based locations are declining as a result of too frequent fires. This species qualifies for listing as Endangered under criterion B.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
This species is known from the Cape Peninsula, in the Western Cape Province of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Peninsula Sandstone Fynbos
Description
It occurs in rocky places in sandstone fynbos, at 70-310 m.a.s.l. 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 germinate following fire. It is pollinated by insects.
Threats
This species is experiencing slow but ongoing degradation of its habitat due to too frequent fires, the Cape Point Section of this species' range where the majority of individuals are concentrated has experienced fires every 8 years for the past 25 years, a natural fire cycle would be between 15 and 20 year. Invasive alien acacias are also a threat especially to the subpopulation occurring at Rooikraans.
Population

It is known from between four and six extant subpopulations, the largest subpopulations occur within the Cape Point section of Table Mountain National Park with subpopulations numbering several hundred mature individuals occurring at Bonteberg and Olifantsbos. Smaller subpopulations of fewer than 100 plants occur within this same Cape Point location at Anvil Rocks, and Kommetieberg. Two small subpopulations occur on the mountains between Kommetjie and Simon�s Town, these are Rooikrans where the subpopulation consists of 20-30 plants and another on Manelkofkop which may be extinct as three plants were last recorded here in 2008. Other historically recorded subpopulations that have gone extinct are from Slangkop last recorded in 1950 and Tuinkop last recorded in 1971. The population is suspected to be declining slowly as a result of too frequent fires.


Population trend
Decreasing
Conservation
All extant subpopulations are in the Cape of Good Hope Nature Reserve section of the Table Mountain National Park.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Serruria decumbens (Thunb.) R.Br.EN B1ac(iv)+2ac(iv)Raimondo et al. (2009)
Serruria decumbens (Thunb.) R.Br.Rare 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.


Helme, N.A. and Trinder-Smith, T.H. 2006. The endemic flora of the Cape Peninsula, South Africa. South African Journal of Botany 72(2):205-210.


Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical 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.


Citation
Rebelo, A.G., Raimondo, D. & von Staden, L. 2020. Serruria decumbens (Thunb.) R.Br. National Assessment: Red List of South African Plants version . Accessed on 2025/04/18

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Distribution map


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