Taxonomy
Scientific Name
Drosanthemum worcesterense L.Bolus
Higher Classification
Dicotyledons
Family
AIZOACEAE
National Status
Status and Criteria
Endangered B1ab(iii)+2ab(iii)
Assessment Date
2018/10/03
Assessor(s)
L. von Staden
Justification
Drosanthemum worcesterense is a range-restricted species with an extent of occurrence (EOO) of 2124 km². It has lost >60% of its habitat to urban and agricultural expansion. Two to four severely fragmented subpopulations remain, and continue to decline due to ongoing habitat loss and degradation.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
This species occurs in the Breede River Valley between Tulbagh and Worcester and extends eastwards to Touwsrivier and Karoopoort.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Breede Shale Renosterveld, Matjiesfontein Shale Renosterveld, Breede Alluvium Renosterveld, Robertson Karoo
Description
It occurs in stony clay soils in renosterveld.
Threats
Critically little of this species' lowland renosterveld remains within the Breede River Valley, predominantly due to loss to agricultural expansion. Known subpopulations occur on isolated remnants, and continue to decline, particularly due to development around Worcester. Around Touwsrivier and Karoopoort, lowland renosterveld is extensively degraded due to overgrazing, and have also been ploughed in places. Drosanthemum species are highly palatable and decline rapidly in overgrazed areas.
Population

This species is known from only three collections in the last 30 years. Two of these localities are extremely small fragments where the subpopulations are unlikely to persist in the long term. Three more locations known through historical records need to be surveyed to determine if the species is still present in these areas. A continuing decline is inferred from ongoing habitat loss and degradation.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Drosanthemum worcesterense L.BolusVU B1ab(i,ii,iii,iv,v)2017.1
Drosanthemum worcesterense L.BolusThreatened Raimondo et al. (2009)
Bibliography

Bolus, H.M.L. 1928-1935. Notes on Mesembrianthemum and allied genera. Part II. Bolus Herbarium, University of Cape Town, Cape Town.


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.


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.


Citation
von Staden, L. 2018. Drosanthemum worcesterense L.Bolus. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/10/25

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Distribution map


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