SANBI

Rationale

This range-restricted endemic occurs in the Western Cape Province, South Africa (EOO 120 km2, AOO 24 km2). There are four locations. There are threats to some of the subpopulations because of habitat degradation, with a decreasing trend in population numbers. The taxon thus qualifies globally under the IUCN criteria as Endangered under criterion B. Since the previous assessment there has been a significant decline in the population size of the largest know sub population at Still Bay. The change in status from Vulnerable to Endangered is genuine.

Distribution

Endemic to the Western Cape Province in South Africa, in the southern Cape coastal region between Vermaaklikheid in the west and Still Bay in the east.

Decline

At some of the known localities the habitat is becoming overgrown with woody elements because of suppression of fire and the absence of grazing by domestic and wild animals.

Habitat View more ecological information

Population trend

Trend

The five subpopulations are as follows: 1. Pauline Bohne Nature Reserve - one large subpopulation spread over a distance of 1.2 km. 2. Still Bay West - one small, isolated subpopulation, 2.5 km from the nearest subpopulation in Pauline Bohne Nature Reserve. 3. Kransfontein - one small, isolated subpopulation 4.7 km from Still Bay West. 4. Langhoogte - one small, isolated subpopulation 4.4 km from Kransfontein. 5. Vermaaklikheid area (30 km from Still Bay) - one isolated but fairly large subpopulation, spread over 650 m.

Threats

Some subpopulations have been lost due to urban expansion, particularly in the Still Bay area, and this trend continues. Thestor populations are only sustainable if the veld has a natural fire and grazing regime. In the absence of fire and grazing the habitat becomes overgrown with woody elements and is then not open enough to maintain populations of the host ant Anoplolepis custodiens.

Conservation

Action should be taken to secure known localities close to Still Bay and Vermaaklikheid before these are lost to development or agriculture. Further exploration should be done to find other colonies elsewhere in this area. The spread of alien plants close to the existing known localities should be monitored.

References

[@book{772,
 address = {Johannesburg &Cape Town},
 author = {Mecenero, S., Ball, J.B., Edge, D.A., Hamer, M.L., Henning, G.A., Krüger, M., Pringle, E.L., Terblanche, R.F. & Williams, M.C. (eds)},
 publisher = {Saftronics (pty) Ltd and  Animal Demography Unit, University of Cape Town},
 title = {Conservation assessment of butterflies of South Africa, Lesotho and Swaziland: Red List and Atlas.},
 year = {2013}
}
,@book{772,
 address = {Pretoria},
 author = {Henning, G.A., Terblanche, R.F. & Ball, J.B. (eds)},
 publisher = {South African National Biodiversity Institute},
 title = {South African Red Data Book: butterflies. SANBI Biodiversity Series},
 year = {2009}
}
,@article{772,
 author = {SANBI},
 journal = {South African National Biodiversity Institute},
 pages = {0},
 title = { Vegetation Map of South Africa, Lesotho and Swaziland [vector geospatial dataset] 2012. Available from the Biodiversity GIS website.},
 volume = {0},
 year = {2012}
}
,@book{893,
 author = {Williams, M.C.},
 publisher = {CD-ROM. Available from the author at mark.williams[at]up.ac.za.},
 title = {Butterflies and skippers of the Afrotropical Region.},
 year = {2016}
}
,@article{21749,
 author = {Heath, A. & Pringle, E.L.},
 journal = {Metamorphosis},
 pages = {90--151},
 title = {A review of the southern African genus <i>Thestor<i> Hübner (Lepidoptera: Lycaenidae: Miletinae)},
 volume = {15},
 year = {2004}
}
,@article{161318795,
 author = {Claassens, A.J.M. & Heath, A.},
 journal = {Metamorphosis},
 pages = {56--61},
 title = {Notes on the myrmecophilous early stages of two species of <i>Thestor</i> Hübner (Lepidopter: Lycaenidae) from South Africa.},
 volume = {2},
 year = {1997}
}
,@article{161318795,
 author = {Heath, A. & Claassens, A.J.M.},
 journal = {Metamorphosis},
 pages = {19--Mar},
 title = {New observations of ant associations and life history adaptations (Lepidoptera: Lycaenidae) in South Africa.},
 volume = {11},
 year = {2000}
}
,]

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