Dioscorea burchellii | SANBI Sensitive Species

Assessor: Sarah Schumann

Sensitive in 2010

Family

Amaryllidaceae

Reason for the sensitivity status

This genus is in demand and of popular interest in international horticultural trade. Another species of this genus was known to be heavily exploited in the past for commercial medicinal production and currently continues to be utilized in local medicinal plant trade. Few known locations of occurrence with existing threat causing population decline makes this species vulnerable to population loss. Were exploitation to also occur, recruitment and recovery may be poor. Releasing data on this species could exacerbate threat and vulnerability.

This species is either similar to or belongs to a group containing sensitive species, and is extremely rare in the wild. The localities of wild populations need to be protected to avoid loss to exploitation, which, due to its rarity, could drive the species to extinction within a very short time.

Exploitation extent

Uncertain - No data exists yet showing that this species is exploited in the wild, however it has one or more relatives or look-alike species (found in South Africa or globally) that are known to be utilised. This species has a similar life form or other relevant traits to its exploited relative(s), making it highly likely that it would be exploited for the same purposes.

Justification and references

According to the SANBI Red List Assessment, this species is Vulnerable as it is rare, range-restricted and experiencing population decline due to habitat loss and degradation (von Staden & Wilkin, 2016). Another species of this genus was known to be heavily exploited in the past for commercial medicinal production and currently continues to be utilized in local medicinal plant trade (Williams et al. 2008; Dold & Cocks, 2002; Williams et al. 2007). This genus is in demand and of popular interest in international horticultural trade, as indicated by several online marketplace, e-commerce and auction sites. Another species of this genus has been confiscated from illegal collection (Confiscation list (2021-2022) provided by Kirstenbosch Botanical Garden, Karoo Desert Botanical Garden, and SANparks Sendlingsdrift). This suggests that this genus may be targeted and that this species may be at risk.

Dold, A.P. and Cocks, M.L. 2002. The trade in medicinal plants in the Eastern Cape Province, South Africa. South African Journal of Science 98:589-597.

von Staden, L. & Wilkin, P. 2016. Dioscorea burchellii Baker. National Assessment: Red List of South African Plants version 2020.1.

Williams, V.L., Witkowski, T.F. and Balkwill, K. 2007. Volume and financial value of species traded in the medicinal plant markets of Gauteng, South Africa. International Journal of Sustainable Development & World Ecology 14(6):584-603

Williams, V.L., Raimondo, D., Crouch, N.R., Cunningham, A.B., Scott-Shaw, C.R., Lötter, M. & Ngwenya, A.M. 2008. Dioscorea sylvatica Eckl. National Assessment: Red List of South African Plants version 2020.1.

Population vulnerability

Population is vulnerable: size is <= 2500 mature individuals OR the number of known subpopulations is <= 5 OR range is <= 100km² OR species at risk of localised extinctions

Justification and references

This taxon has an extent of occurrence of 1310 km² and is known from less than 10 locations with a declining population size (von Staden & Wilkin, 2016).

von Staden, L. & Wilkin, P. 2016. Dioscorea burchellii Baker. National Assessment: Red List of South African Plants version 2020.1.

Targeted demographics

Unknown.

Regeneration potential

This species has a slow population growth rate, or the growth rate varies depending on habitat, and there is a poor chance the wild populations will recover from exploitation OR a collector might feasibly harvest the entire extant population removing the chance of subsequent recruitment.

Justification and references

Few known locations of occurrence with existing threat (von Staden & Wilkin, 2016), makes this species vulnerable to population loss. Were exploitation to also occur, recruitment and recovery may be poor.

von Staden, L. & Wilkin, P. 2016. Dioscorea burchellii Baker. National Assessment: Red List of South African Plants version 2020.1.

Reference file

dioscorea _ eBay.pdf1.04 MB

Dioscorea Rakuten.pdf507.95 KB

Dioscorea Aucfan.pdf963.94 KB

Dioscorea burchellii Threatened Species Programme _ SANBI Red List of South African Plants.pdf550.45 KB