Trichodiadema pygmaeum

Taxonomy
Scientific Name
Trichodiadema pygmaeum L.Bolus
Higher Classification
Dicotyledons
Family
AIZOACEAE
National Status
Status and Criteria
Endangered B1ab(iii,v)
Assessment Date
2016/01/18
Assessor(s)
L. von Staden
Justification
EOO 2992 km², 13 severely fragmented remaining subpopulations continue to decline due to ongoing habitat loss and degradation.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Swellendam to Cape Infanta.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Eastern Rûens Shale Renosterveld, Central Rûens Shale Renosterveld, Rûens Silcrete Renosterveld, Western Rûens Shale Renosterveld, Swellendam Silcrete Fynbos, Overberg Dune Strandveld
Description
Quartz outcrops in shale and silcrete renosterveld.
Threats
Less than 10% of shale and silcrete renosterveld in the Overberg remains intact after extensive loss to crop cultivation. This species occurs on somewhat shallower soils that are not suitable for cultivation, but there has been some opportunistic ploughing of some areas in the past. Small remaining fragments are often overstocked with livestock, and grazing and trampling due to overgrazing and overstocking is the most severe ongoing threat to this species, affecting at least 50% of remaining subpopulations. Some sites are also invaded with alien invasive plants, which could potentially outcompete native species if left unmanaged.
Population

About 13 subpopulations are known to remain, and 12 of these occur on small, isolated renosterveld fragments. Field observations indicate that subpopulations are small, and the population is therefore considered severely fragmented. It continues to decline due to ongoing habitat loss and degradation.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Trichodiadema pygmaeum L.BolusVU D2Raimondo et al. (2009)
Trichodiadema pygmaeum L.BolusRare Hilton-Taylor (1996)
Trichodiadema pygmaeum L.BolusIndeterminate 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.


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
von Staden, L. 2016. Trichodiadema pygmaeum L.Bolus. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/08/22

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Distribution map


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