Taxonomy
Scientific Name
Asclepias bicuspis N.E.Br.
Higher Classification
Dicotyledons
Family
APOCYNACEAE
National Status
Status and Criteria
Critically Endangered C2a(i)
Assessment Date
2011/06/16
Assessor(s)
A. Nicholas, I.M. Johnson & D. Raimondo
Justification
EOO 203 km², previously known from only one farm south-west of Howick. Prior to 2009, this species was considered one of the most threatened on the Red List of South African Plants (Raimondo et al. 2009). Extensive surveys by volunteers of the Custodians of Rare and Endangered Wildflowers (CREW) Programme of suitable habitat within this species' range in late 2009 and 2010 have resulted in an additional two subpopulations being found. All three known subpopulations have fewer than 50 mature individuals and are declining due to livestock overgrazing. Total population estimated at <250 and its range has been heavily impacted by agriculture, afforestation, the construction of the Midmar Dam and urban expansion over the past 100 years; very little suitable habitat remains.
Distribution
Endemism
South African endemic
Provincial distribution
KwaZulu-Natal
Range
KwaZulu-Natal Midlands.
Habitat and Ecology
Major system
Terrestrial
Major habitats
KwaZulu-Natal Hinterland Thornveld, Midlands Mistbelt Grassland, Mooi River Highland Grassland, Moist Coast Hinterland Grassland
Description
Mistbelt grassland, in well-drained soil in annually burned grasslands, including firebreaks, 1 200-1 500 m.
Threats
The subpopulation at the type location, Dargle farm, has gone extinct due to heavy over-utilization for cattle farming and pine plantations that were planted in the 1920s. A second historic location near Howick was lost through expansion of Howick. All three of the extant subpopulations are threatened by livestock overgrazing. Volunteers of the CREW Programme noted significant impact of grazing during surveys conducted in 2010. The entire distribution range in which this species occurs has been heavily impacted on by agriculture, afforestation, dam construction and ever increasing urban expansion. Within the known historical range of this species, mistbelt grasslands have been ± 45% transformed (calculated using GIS). KwaZulu-Natal Midlands Mistbelt Grasslands have been classified as Endangered, as 53% of this vegetation type has been transformed and very little is protected (Rouget et al. 2004).
Population

Recorded from three subpopulations the one near Howick had under 10 plants counted during a survey in 2009, the second subpopulation near Greenwich had 30 plants counted during an extensive survey in 2010, the third subpopulation near Boston also has under 10 plants counted during surveys in 2010 but is suspected to be about 30 plants.


Population trend
Decreasing
Conservation
Not currently conserved in any formally protected area.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Asclepias bicuspis N.E.Br.CR B1ab(ii,iii,iv)Raimondo et al. (2009)
Asclepias bicuspis N.E.Br.CR B1B2cScott-Shaw (1999)
Asclepias bicuspis N.E.Br.Extinct Hilton-Taylor (1996)
Bibliography

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


Mucina, L. and Rutherford, M.C. (eds). 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.


Nicholas, A. 1982. Taxonomic studies in Asclepias (Asclepiadeae) with particular reference to the narrow-leaved species in southern Africa. University of Natal.


Nicholas, A. 1999. A taxonomic reassessment of the subtribe Asclepiadinae (Asclepiaceae) in Southern Africa. Unpublished Ph.D., University of Durban-Westville, Durban.


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.


Rouget, M., Reyers, B., Jonas, Z., Desmet, P., Driver, A., Maze, K., Egoh, B. and Cowling, R.M. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 1: Terrestrial component. 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.


Citation
Nicholas, A., Johnson, I.M. & Raimondo, D. 2011. Asclepias bicuspis N.E.Br. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/04/18

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Distribution map

© D. Clulow

© D. Clulow

© H. Mtshali

© H. Mtshali

© H. Mtshali

© H. Mtshali

© M. Mkhize

© I.M. Johnson

© I.M. Johnson


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