Red List of South African Species

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Vulnerable (VU)
Assessors: Mark Williams
Facilitators: Mark Williams
Reviewers: Silvia Kirkman Domitilla Raimondo Rolf Oberprieler

Rationale

A species found in Mpumalanga and Limpopo provinces in South Africa as well as in Swaziland (EOO 3 585 km<sup>2</sup>). Recently discovered subpopulations near Ohrigstad, Barberton and in Swaziland, since the last assessment in 2013, have significantly increased both the EOO and AOO. There are six subpopulations, two of which are in protected areas. Together with a third subpopulation near Ohrigstad, these three subpopulations are in relatively pristine grassland habitat suitable for the species. Plantations are absent here and unlikely to be planted because of the rocky, mountainous terrain. The subpopulations at Nelshoogte, Sabie and Graskop are experiencing ongoing decline in habitat quality as a result of fire suppression for Pine plantation management (the host plant requires fire) and invasion by alien plants. The taxon thus qualifies globally under the IUCN criteria as Vulnerable under criterion B. Since the 2012 assessment two new localities for this taxon have been found, near Ohrigstad and near Barberton. Both are in unthreatened habitats and the Barberton locality is situated in a protected area. Very recently (October 2017), C. Dobson (J. Dobson, pers. comm.) found a subpopulation near the type locality at Nelshoogte. This new information has increased the estimated EOO from 850 km<sup>2</sup> in the 2012 assessment to 3 585 km<sup>2</sup> in the current assessment. These new localities would've existed during the 2012 assessment and thus six locations would've been valid then too, placing it in the Vulnerable category. The status change from Endangered to Vulnerable is therefore non-genuine change.

Distribution

From Mpumalanga and Limpopo provinces in South Africa, and from Swaziland, along the Drakensberg escarpment from Malolotja National Park in the south to near Ohrigstad in the north.

Decline

In the Graskop, Sabie and Nelshoogte subpopulations severe fragmentation of the habitat has been caused by massive pine and blue-gum plantation development on the escarpment. Alien vegetation, in the form of black wattle, bramble, bug-weed and others, is causing further modification of the habitat. The host plant, Becium obovatum, is dependent on regular fire in order to thrive. Fires in the grassland patches are deliberately suppressed because of the danger to the plantations, leading to massive loss of grassland biodiversity (see references in Henning et al., 2009). However, the subpopulations in Swaziland, near Barberton and near Ohrigstad are all under no threat (pers. obs.).

Population trend

Trend

In recent years three further subpopulations have been found in a protected area in Swaziland, in a protected area near Barberton and in the mountains above Ohrigstad. None of these populations are threatened and all appear to be stable.

Threats

Moderate fragmentation of the habitat has been caused by Pine and Blue-gum plantation development on the escarpment. Alien vegetation, in the form of Black Wattle, Bramble, Bug-weed and others, is causing further modification of the habitat. The host plant, <i>Ocimum obovatum</i>, is dependent on regular fire in order to thrive. Fires in the grassland patches are deliberately suppressed because of the danger to the plantations, leading to loss of grassland biodiversity. However, the subpopulations in Swaziland, near Barberton and near Ohrigstad are all under no threat (M. Williams, pers. obs.).

Conservation

A management plan that protects and manages the Nelshoogte, Sabie and Graskop subpopulations should be developed and implemented.

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{882,
 address = {Cape Town},
 author = {Pringle, E.L., Henning, G.A. & Ball, J.B. (eds)},
 publisher = {Struik-Winchester},
 title = {Pennington's Butterflies of southern Africa.},
 year = {1994}
}
,@article{890,
 author = {Mucina, L. & Rutherford, M.C. (eds)},
 journal = {Strelitzia},
 pages = {0},
 title = {The Vegetation of South Africa, Lesotho and Swaziland.},
 volume = {19},
 year = {2006}
}
,]
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