Brachystelma natalense

Taxonomy
Scientific Name
Brachystelma natalense (Schltr.) N.E.Br.
Higher Classification
Dicotyledons
Family
APOCYNACEAE
Synonyms
Aulostephanus natalensis Schltr.
National Status
Status and Criteria
Critically Endangered B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(ii)
Assessment Date
2016/12/07
Assessor(s)
L. von Staden & D. Styles
Justification
EOO <10 km², AOO <0.12 km², the habitat of this rare species has been extensively destroyed and fragmented by urban expansion, crop cultivation and overgrazing. It now remains as two small, non-viable subpopulations occurring on isolated grassland fragments. Although the largest subpopulation (of about 50 individuals) is protected in a reserve, monitoring has shown continuing declines in the number of mature individuals and a complete lack of recruitment. The habitat of a second, smaller subpopulation of six individuals is severely threatened by invasive wattles.
Distribution
Endemism
South African endemic
Provincial distribution
KwaZulu-Natal
Range
Pinetown.
Habitat and Ecology
Major system
Terrestrial
Major habitats
KwaZulu-Natal Sandstone Sourveld
Description
Ngongoni grassland, Natal Group Sandstone, 450-500 m.
Threats
The habitat of this species between Durban and Pietermaritzburg, KwaZulu-Natal Sandstone Coastal Sourveld (formerly known as Ngongoni veld according to Acocks system), is 81% transformed by urban expansion, crop cultivation and degradation due to overgrazing of rural communally owned rangelands (Ngwenya et al. 1995, Singh et al. 1997). This destruction is thought to have caused the loss of the type locality near Inanda (Ngwenya et al. 1995, Singh et al. 1997). One small subpopulation was saved from destruction when it was discovered during an environmental impact study for a housing development. However, the development further reduced the size of the grassland fragment, and the site became heavily infested with alien invasive wattles. eThekwini Municipality recently cleared the wattles (L. Ground pers. comm. 2016), but ongoing management and rehabilitation of the site will be required to ensure the persistence of this subpopulation. The largest known subpopulation has been found to be declining for unknown reasons during a five year monitoring period. This subpopulation occurs in a nature reserve and there are no apparent threats, except for parts of the site becoming encroached with Bracken Fern (Pteridium aquilinum). This subpopulation is also showing no signs of recruitment. The insect pollinator seems to have disappeared from the small protected grassland fragment surrounded by urban areas, as no fruiting has been observed in the subpopulation over the monitoring period. Attempts to hand-pollinate the flowers have been unsuccessful (Ngwenya et al. 1995, Singh et al. 1997), but ex-situ breeding using tissue culture is being explored as an alternative option (L. Ground pers. comm. 2016).
Population

Six plants occur on a two hectare patch of municipal land at Alverstone. According to Scott-Shaw (1999) there were 57 plants in the Kranzkloof Nature Reserve in 1999. D. Styles monitored the population for a number of years and estimates that the number of individuals has declined over the last few years and that there were 37 or less individuals. However, according to B. Church (Threatened Plant Conservation Unit, Ezemvelo-KZN Wildlife), there are still 57 plants occurring in two separate patches in the Kranzkloof reserve (B. Church pers. comm. 2007). In a 2016 survey, only six plants could be located (L. Ground pers. comm. 2016).


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Brachystelma natalense (Schltr.) N.E.Br.CR B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i)Raimondo et al. (2009)
Brachystelma natalense (Schltr.) N.E.Br.VU D2Victor (2002)
Brachystelma natalense (Schltr.) N.E.Br.CR B1B2abcde,D1Scott-Shaw (1999)
Brachystelma natalense (Schltr.) N.E.Br.Endangered Hilton-Taylor (1996)
Bibliography

Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.


Ngwenya, M.A., Singh, Y., Crouch, N.R., Scott-Shaw, C.R. and Sikhakhane, T.B. 1995. Brachystelma natalense: rediscovered and redescribed. Aloe 32(2):44-43.


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.


Scott-Shaw, C.R. 1999. Rare and threatened plants of KwaZulu-Natal and neighbouring regions. KwaZulu-Natal Nature Conservation Service, Pietermaritzburg.


Singh, Y., Nicholas, A. and Pooley, E. 1997. Brachystelma natalense. Flowering Plants of Africa 55:96-101.


Styles, D. 2006. Some new and interesting records from greater Durban. PlantLife 32:33-35.


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.


Wragg, P. 2006. Conservation status of threatened milkweeds (Apocynaceae) of the Natal Group Sandstone Grasslands: Brachystelma natalense (Schltr.) N.E.Br., B. pulchellum (Harv.) Schltr., and Schizoglossum peglerae N.E. Br. University of KwaZulu-Natal, Unpublished essay.


Citation
von Staden, L. & Styles, D. 2016. Brachystelma natalense (Schltr.) N.E.Br. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2018/11/16

Comment on this assessment Comment on this assessment
Distribution map

© R. Boon

© R. Boon

© D. Styles

© D. Styles

© D. Styles

© D. Styles

© D. Styles

© D. Styles

© D. Styles


Search for images of Brachystelma natalense on iSpot