Dioscorea strydomiana Wilkin
Status and Criteria
Critically Endangered B1ab(v)+2ab(v); C1
|L. von Staden, J.E. Victor, D. Raimondo & P.J.H. Hurter|
|Recently discovered, known from one location and fewer than 250 mature individuals. The tubers of this species are used as medicine by the Ebutsini tribe, on whose tribal land the only known subpopulation occurs. Medicinal harvesting is causing a continuing decline in the of number of mature individuals. It appears to be a very slow growing species (generation length estimated to be 50 years). There has been at least a 25% decline in the number of mature individuals in the past 150 years as a result of medicinal harvesting.|
|South African endemic|
Habitat and Ecology
|Exposed, open grassland, in serpentine soils on steep, southeast-facing slopes, 1100 m.|
|The main threat to this species is harvesting of tubers for traditional medicine, which monitoring has shown to be unsustainable as the population is very small and plants are extremely slow growing. The species is also potentially threatened by collection for horticultural purposes, as it has an attractive pachycaul growth form, but being very slow growing it is likely to be difficult to establish in cultivation, which may put pressure on the wild population to meet commercial demand. Mining is another potential future threat - a prospecting application for the property was recently submitted.|
The population of about 250 plants has been monitored annually since 2007. Harvesting damage has been noted in 91% of tagged individuals, and 32% of monitored individuals have died due to overharvesting since 2008.
|This species has great horticultural potential. Conservation measures by means of propagation in cultivation have been put in place (Hurter 2003).|
Status and Criteria
Citation/Red List version
|Dioscorea sp. nov. (Hurter 106 GLOW, PRU)||CR B1ab(v)+2ab(v); C1||Raimondo et al. (2009)|
Hurter, J. 2003. A new pachycaul Dioscorea species from Mpumalanga Province, South Africa and its conservation. Aloe 40(3&4):73-75.
Hurter, P.J.H. and van Wyk, A.E. 2004. A new species of Acacia (Mimosoideae) from Mpumalanga, South Africa: Acacia ebutsiniorum. Bothalia 34(1):42-44.
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.
Wilkin, P., Burrows, J., Burrows, S., Muasya, A. and Van Wyk, E. 2010. A critically endangered new species of yam (Dioscorea strydomiana Wilkin, Dioscoreaceae) from Mpumalanga, South Africa. Kew Bulletin 65(3):421-433.
|von Staden, L., Victor, J.E., Raimondo, D. & Hurter, P.J.H. 2011. Dioscorea strydomiana Wilkin. National Assessment: Red List of South African Plants version 2015.1. Accessed on 2016/10/01|