Red List of South African Species

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Vulnerable (VU)
Assessors: Michael Samways
Contributors: Frank Suhling
Facilitators: Dewidine Van Der Colff
Reviewers: Domitilla Raimondo

Rationale

This species has a relatively wide distribution, occurring in river catchments of the Zambezi and Limpopo. Its occurrence outside the southern Africa region (record from Tanzania) has still to be confirmed. Assessed as Least Concern in view of its wide distribution, and because it is unlikely to be declining fast enough to qualify for listing in a threat or Near Threatened category. However, in South Africa it is marginal and appears to be highly susceptible to extreme drought events, causing habitat degradation. Searches in recent years have produced few records, and it appears to expand and remain resident for a short while and then retreat during drought years. It is known from an area of occupancy (AOO) of 28 kmand from five locations. It qualifies as Endangered B2ab(iii), however since this is a regional assessment at the national level, a regional adjustment is made to the assessment as there is a potential of migration from neighbouring populations, the species is thus assessed as Vulnerable B2ab(iii).

Distribution

This species may be endemic to the southern Africa region. It occurs in the river catchments of the Zambezi and the Limpopo (Botswana, Mozambique, South Africa Zambia, and Zimbabwe). However, there is also an unconfirmed record from Tanzania. In South Africa, there are only three early records: two from the Kruger National Park, and one from Ndumo, KwaZulu-Natal (Samways and Simaika 2016).

Population trend

Trend

No information is available on overall population size or trends. It appears to be a localised species throughout its range (Samways 2006). In South Africa, it appears to be resident for a while and then disappear, to re-establish later.

Threats

In South Africa the species is highly susceptible to climatic conditions driving droughts and flooding events. Major changes to the river systems of the Kruger National Park as a result of the floods of February 2000 may have altered its habitat, particularly that of the larvae (Samways 2006). The species retreat during drought years and return in more favorable years. Climate change is affecting drought/flood cycles and may be a more severe threat in future.

Conservation

In South Africa, further searches for the species are required (Samways 2006). No specific conservation measures are known to be in place or planned at present.

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