Taxonomy
Scientific Name
Hoodia pilifera (L.f.) Plowes subsp. annulata (N.E.Br.) Bruyns
Higher Classification
Dicotyledons
Family
APOCYNACEAE
Synonyms
Hoodia annulata (N.E.Br.) Plowes, Trichocaulon annulatum N.E.Br.
National Status
Status and Criteria
Vulnerable B1ab(v)
Assessment Date
2019/11/04
Assessor(s)
D. Raimondo
Justification
This taxon has a restricted distribution range, with an extent of occurrence (EOO) of 5594 km². It is known from eight locations, and is declining for unknown reasons.
Distribution
Endemism
South African endemic
Provincial distribution
Eastern Cape, Western Cape
Range
This taxon occurs in the southern Great Karoo from Aberdeen and Graaff-Reinet southwards to Rietbron and eastwards to Willowmore, Klipplaat and Steytlerville.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Eastern Gwarrieveld, Willowmore Gwarrieveld, Steytlerville Karoo, Prince Albert Succulent Karoo, Gamka Karoo, Eastern Lower Karoo
Description
It occurs on flat areas between low hills on slightly gravelly ground, rarely on hill slopes.
Threats
Large-scale shale gas fracking was proposed in 2015 for the Karoo basin, covering a large portion of this taxon's range. Subpopulations on flats would be most vulnerable to habitat loss to infrastructure development related to fracking, and this species could decline in future if fracking goes ahead. A Strategic Environmental Impact Assessment submitted to South Africa's Department of Environment Affairs in 2016 cautioned against moving ahead with Shale Gas fracking based on the very high infrastructure costs associated with fracking as well as multiple secondary negative impacts both to biodiversity and other economic activities in the region. Furthermore, subsequent geological studies found that gas deposits are not as substantial as original suspected, due to the very old age of the Karoo shale formations as well as widespread dolerite intrusions which resulted in much of the gas being lost. At present, future development scenarios are too uncertain to estimate the potential extent of the impact on the population, but it is unlikely that shale gas fracking will proceed in the near future.
Population

This taxon is rare, occurring as widely scattered individuals. There are often several hundred meters between plants, one subpopulation east of Willowmore was found to include more than 50 large plants (Bruyns 2005). Many large mature individuals of the subpopulation near Aberdeen died in 2013. The cause of death is not known. It is expected to continue to decline, and the population requires monitoring.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Hoodia pilifera (L.f.) Plowes subsp. annulata (N.E.Br.) BruynsLeast Concern Raimondo et al. (2009)
Hoodia pilifera (L.f.) Plowes subsp. annulata (N.E.Br.) BruynsRare Hilton-Taylor (1996)
Trichocaulon annulatum N.E.Br.Rare Hall et al. (1980)
Bibliography

Bruyns, P.V. 1993. A revision of Hoodia and Lavrania (Asclepiadaceae-stapelieae). Botanische Jahrbücher für Systematik 115(2):145-270.


Bruyns, P.V. 2005. Stapeliads of southern Africa and Madagascar. (Vol. 1, pp. 1-330). Umdaus Press, Pretoria.


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.


Citation
Raimondo, D. 2019. Hoodia pilifera (L.f.) Plowes subsp. annulata (N.E.Br.) Bruyns. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/07/10

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Distribution map


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