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Disa tysonii

Assessor: Sarah Schumann

Sensitive in 2010
No
Family
Orchidaceae
Reason for the sensitivity status
Other species in this genus are known to be threatened by collection of wild individuals. A rare and small population size makes this species vulnerable to population loss. Were exploitation to occur, recruitment and recovery may be poor. Releasing data on this species could exacerbate threat and vulnerability.
This species is either similar to another sensitive species 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 widespread, rare and localized with a few small subpopulations that is not thought to be declining (Victor & Scott-Shaw, 2006). Other species in this genus are known to be threatened by collection of wild individuals (von Staden et al. 2012; von Staden & Liltved, 2012).

Victor, J.E. & Scott-Shaw, C.R. 2006. Disa tysonii Bolus. 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. & 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. 

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 is known from a few small subpopulations, is widespread, rare and localized (Victor & Scott-Shaw, 2006).

Victor, J.E. & Scott-Shaw, C.R. 2006. Disa tysonii Bolus. 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

Rarity and few small subpopulations makes this species vulnerable to population, were exploitation to occur.

Reference file
Disa tysonii Threatened Species Programme _ SANBI Red List of South African Plants.pdf541.31 KB