Villiersdorp Ridge-cone Conebush

Taxonomy
Scientific Name
Leucadendron comosum (Thunb.) R.Br. subsp. homaeophyllum (Meisn.) I.Williams
Higher Classification
Dicotyledons
Family
PROTEACEAE
Synonyms
Leucadendron aemulum R.Br. var. homaeophyllum Meisn.
Common Names
Villiersdorp Ridge-cone Conebush (e)
National Status
Status and Criteria
Critically Endangered C2a(ii)b; D
Assessment Date
2019/08/13
Assessor(s)
A.G. Rebelo, D. Raimondo & L. von Staden
Justification
An endemic to the mountains of the south western Cape South Africa, this species has an extent of occurrence (EOO) of between 1-44 km², and an area of occupancy of between 12 and 16 km². Three small, isolated subpopulations occur with the possibility that one of the subpopulations has already gone extinct as result of wildflower harvesting. Extreme fluctuations is inferred from the fact that this species is a serotinous reseeder known to undergo density-dependent population fluctuations of one to three orders of magnitude in response to fire (Bond et al. 1995). There is ongoing decline in habitat quality due to alien plant invasion and inappropriate fire management. The entire population at present consists of fewer than 50 mature individuals. It therefore qualifies as Critically Endangered under criteria C and D.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Aasvoelberg above Kaaimansgat and Du Toit's Kloof Pass.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Hawequas Sandstone Fynbos, Boland Granite Fynbos
Description
Sandstone fynbos at high altitude and granite fynbos at mid altitudes. Mature individuals are killed by fires, and only seeds survive. Wind-dispersed seeds are stored in fire-resistant inflorescences, and released after fires. It is dioecious, with insect-pollinated male and female flowers occurring on separate plants.
Threats
This species is threatened by harvesting for the cut flower industry with documented loss of the females from the population at Du Toit's Kloof as a result of harvesting. Invasive species of pine and hakea and too frequent fires are severe threats to both known locations.
Population

Three small subpopulations have been recorded in the past 20 years, the first at Du Toit's Kloof Pass consisted of only 10 plants in 1998 with only one female, all cones were harvested for the cut flower trade and it is suspected that no seeds remained. No more plants have been seen at this site since 2002 and it may be extinct. A single herbarium collection exists from Aasvoelberg collected in the 1980s however despite atlasing taking place on this mountain range during the Protea Atlas project (1992 to 2002), no plants were recorded. The last subpopulation is from Bloukop where a single patch of 20 plants were last recorded in 2002 in an area of 20 m x 5 m.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Leucadendron comosum (Thunb.) R.Br. subsp. homaeophyllum (Meisn.) I.WilliamsCR B1ab(i,ii,iii,iv,v)c(iv)+2ab(i,ii,iii,iv,v)c(iv); DRaimondo et al. (2009)
Leucadendron comosum (Thunb.) R.Br. subsp. homaeophyllum (Meisn.) I.WilliamsNot Threatened Hilton-Taylor (1996)
Leucadendron comosum (Thunb.) R.Br. subsp. homaeophyllum (Meisn.) I.WilliamsExtinct Hall et al. (1980)
Bibliography

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.


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. 2019. Leucadendron comosum (Thunb.) R.Br. subsp. homaeophyllum (Meisn.) I.Williams. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/09/23

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Distribution map

© C. Paterson-Jones

© C. Paterson-Jones


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