Red List of South African Species

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Critically Endangered (CR)
B1ab(iii)+2ab(iii)

Rationale

Castleton's Flightless Katydid (Austrodontura castletoni) is Critically Endangered under criteria B1 and B2 because it has a small area of occupancy and extent of occurrence (8 km2 each), has been found only at two localities, has a severely fragmented distribution, and its area, extent and quality of habitat are estimated to be in decline. This species occurs only within Silaka Nature Reserve, Eastern Cape, South Africa, within the Indian Ocean Coastal Belt indigenous forest biome, a habitat type which is severely fragmented. Due to its highly restricted distribution even a small disturbance can have a detrimental effect on the survival of the species as a whole. The most likely threats to the species are deforestation, land use transformation of its natural habitat, habitat destruction as a result of invasive alien plants, particularly Lantana camara, or change in microclimate or distribution of the species' food plants as a result of climate change. Due to its small body size and low motility, this species cannot be expected to shift its range in response to changes in its habitat. 

Distribution

Castleton's Flightless Katydid is known only from two locations in Silaka Nature Reserve, Eastern Cape Province, South Africa.

Population trend

Trend

No information on population sizes or trends is available.

Threats

Due to its severely restricted distribution, Castleton's Flightless Katydid is particularly prone to any changes in its habitat. The most likely disturbances are habitat destruction in the form of deforestation or land use transformation to cultivated land or plantation forestry. Invasive plants such as Lantana camara may also threaten the future survival of this species, as may climate change-associated variation in weather patterns which can affect the distribution of this species’ food plant and microhabitat conditions. Likely threats include droughts, floods, wildfires, and extreme temperature fluctuations. 

Uses and trade

This species is not utilized.

Conservation

No specific conservation measures are in place for this species but it is known to occur in at least one protected area, Silaka Nature Reserve. 

Lead agencies, Partners and Funders

See the partners page