Brachystelma dimorphum subsp. dimorphum

Taxonomy
Scientific Name
Brachystelma dimorphum R.A.Dyer subsp. dimorphum
Higher Classification
Dicotyledons
Family
APOCYNACEAE
National Status
Status and Criteria
Vulnerable B2ab(iii,v)
Assessment Date
2016/08/24
Assessor(s)
N. Hahn & L. von Staden
Justification
A widespread (EOO 22 158 km²), but localized habitat specialist (AOO estimated to be <2000 km²). It is known from fewer than 10 locations, but might be overlooked. It is suspected to be declining due to ongoing loss and degradation of its habitat.
Distribution
Endemism
South African endemic
Provincial distribution
Free State, Northern Cape, North West
Range
Kimberley to Vryburg and Bloemfontein.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Southern Kalahari Salt Pans, Highveld Salt Pans, Winburg Grassy Shrubland, Kimberley Thornveld
Description
Alluvial soils and large, shallow pans in grassland.
Threats
This taxon is threatened across its range by ongoing habitat loss and degradation, particularly agricultural expansion on alluvial soils, as well as spreading settlements, mining, alien invasive plants and degradation due to overgrazing.
Population

This taxon is known from only five collections, scattered over a wide area, and was last recorded in 1971. It is possibly localized to salt pans - three of the records are from areas surrounding salt pans - which may explain its rarity, areas of suitable habitat would be generally small in extent, and widely scattered. Its distribution range is however botanically very poorly sampled, and in addition, it is a cryptic species, which would make it easily overlooked (Hahn 2013). It is possibly more common, but field surveys are needed to relocate it in the wild, and to gain a better understanding of its habitat preferences, population size and status. Searches at known localities near Kimberley and in North West Province have thus far failed to relocate these subpopulations.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Brachystelma dimorphum R.A.Dyer subsp. dimorphum Least Concern Raimondo et al. (2009)
Brachystelma dimorphum R.A.Dyer subsp. dimorphum Lower Risk - Least Concern Victor (2002)
Brachystelma dimorphum R.A.Dyer subsp. dimorphum Indeterminate Hilton-Taylor (1996)
Bibliography

Dyer, R.A. 1979. ASCLEPIADACEAE: New records of Brachystelma. Bothalia 12(4):627-629.


Dyer, R.A. 1980. Brachystelma, Ceropegia and Riocreuxia. In: O.A. Leistner (ed). Flora of Southern Africa 27 Part 4:1-88. Botanical Research Institute, Pretoria.


Dyer, R.A. 1983. Ceropegia, Brachystelma and Riocreuxia in southern Africa. A.A. Balkema, Rotterdam, Netherlands.


Hahn, N. 2013. Rare, endangered and endemic flora of the North West Province. Unpublished Report to the Department of Economic Development, Conservation and Tourism, North West Provincial Government.


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.


Victor, J.E. 2002. South Africa. In: J.S. Golding (ed), Southern African plant Red Data Lists. Southern African Botanical Diversity Network Report 14 (pp. 93-120), SABONET, Pretoria.


Citation
Hahn, N. & von Staden, L. 2016. Brachystelma dimorphum R.A.Dyer subsp. dimorphum. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/10/17

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Distribution map


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