Gerrardanthus tomentosus

Assessor: Sarah Schumann

Sensitive in 2010
No
Family
Cucurbitaceae
Reason for the sensitivity status
This species is thought to be potentially threatened by harvesting for medicinal and firewood purposes. Another species of the genus is harvested for medicinal use and it is thought that G. tomentosus could be mistaken for that species. Few known locations of occurrence and a small population with existing potential threats 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 Vulnerable as it is known from 5 sites that are potentially threatened by harvesting for medicinal and firewood purposes as well as by habitat degradation (Styles et al. 2007). At one known site firewood collection in the area may change the structure of its habitat (Styles et al. 2007). Another species of the genus, Gerrardanthus macrorhizus is harvested for medicinal use and it is thought that G. tomentosus could be mistaken for that species, however surveys at the medicinal markets in Durban have not observed the species (Styles et al. 2007).

Styles, D., Scott-Shaw, C.R., Raimondo, D. & von Staden, L. 2007. Gerrardanthus tomentosus Hook.f. 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 five sites with an estimated population size of less than 1000 mature individuals (Styles et al. 2007).

Styles, D., Scott-Shaw, C.R., Raimondo, D. & von Staden, L. 2007. Gerrardanthus tomentosus Hook.f. 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 and a small population with existing potential threats (Styles et al. 2007), places the persistence of this species at risk. Were exploitation to occur, recruitment and recovery may be poor.

Styles, D., Scott-Shaw, C.R., Raimondo, D. & von Staden, L. 2007. Gerrardanthus tomentosus Hook.f. National Assessment: Red List of South African Plants version 2020.1.