Disa newdigateae | SANBI Sensitive Species

Assessor: Juan Swanepoel

Sensitive in 2010

Family

Orchidaceae

Reason for the sensitivity status

Other species in this genus are known to be threatened by collection of wild individuals. Due to existing threat, given the small number of individuals left, if any, exploitation could be detrimental to the population. 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 Critically Endangered and possibly extinct (von Staden, 2012). Other species in this genus are known to be threatened by collection of wild individuals (von Staden et al. 2012, von Staden & Liltved, 2012).

von Staden, L. & Liltved, W.R. 2012. Disa lugens Bolus var. nigrescens (H.P.Linder) H.P.Linder. National Assessment: Red List of South African Plants version 2020.1.

von Staden, L., Oliver, E.G.H. & Raimondo, D. 2012. Disa longicornu L.f. National Assessment: Red List of South African Plants version 2020.1.

von Staden, L. 2012. Disa newdigateae L.Bolus. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/12/30

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

Known from six plants collected between 1895 and 1931 near the Crags, Plettenberg Bay, and none since. The area around the Crags is threatened by housing development and encroachment from invasive alien species, but since information on the precise site is not known, it is hard to say whether or not habitat destruction has led to the extinction of this species. Numerous searches in the area have failed to relocate this species (von Staden, 2012).

von Staden, L. 2012. Disa newdigateae L.Bolus. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/12/30

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

Given the small number of individuals left (if any) exploitation could be detrimental to the population (von Staden, 2012).

von Staden, L. 2012. Disa newdigateae L.Bolus. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/12/30