Brenton Blue Butterfly

Posted by on August 5, 2017

BRENTON BLUE NEWS – JUNE 2017

To all friends and neighbours of the Brenton Blue butterfly –

welcome to your latest newsletter! You can obtain more detailedinformation about the Brenton Blue butterfly itself on the website www.brentonblue.org.za, or about the Brenton Blue Trust at

www.brentonbluetrust.co.za.

 The management committee (MC)for the Brenton Blue includes representatives from CapeNature,

WESSA, EWT, LepSoc Africa, the Knysna Municipality (KM)and local residents.

 

Annual General Meeting (AGM)

The 2017 AGM of the Brenton Blue Trust (BBT) was held on the 27th May 2017. New trustee representatives Jeremy Dobson and Mark Williams attended for the first time. Activities of the BBT were reviewed, and included annual reports of current projects such as the COREL (Custodians of Rare and Endangered Lepidoptera) programme, the SALCA (South African Lepidoptera Conservation Assessment) project, and the

Karoo BioGaps project. Notable achievements during the year under review included:

 

Finalisation of the terms of a contract nature reserve agreement with the KM to expand the Brenton Blue Butterfly Reserve (BBBR) from its original 1.6 ha to and expanded area of 15 ha.

Agreement in principle with Stellenbosch University to create a 1200 ha contract nature reserve near Witsand to conserve Dickson’s Strandveld Opal (Chrysoritis dicksoni). Completion of the research into the ecology of Barber’s False Bay Ranger (Kedestes barberae bunta) at Strandfontein on the Cape Flats.

The financial position of the BBT was currently robust enough to support all foreseen activities for the next two years.

 

The Knysna fire of 7th June 2017

The Knysna fire of 7th June 2017 also raged along the Brenton Peninsula, destroying dozens of homes, many in Brenton-on-Sea, location of the famous BBBR. The 15 ha expanded BBBR (see above) was severely burnt, leaving only very hardy trees such as candlewoods still standing, although badly scorched. After the fire there was no sign of the butterfly’s larval host plant, Indigofera erecta – not unusual because it is currently in its dormant winter state with underground rootstocks.

 

Dr Dave Edge, who received his PhD in 2005 for his work done on the ecology of the butterfly, says that the intensity and extent of this fire was completely unprecedented in living memory, as far back as when Brenton-on-Sea was founded in the mid-1960s. Several factors coincided to produce such a fire. Firstly Brenton (and indeed the whole Garden Route) had over the past nine months experienced a very severe drought, with rainfall less than 25% of the norm experienced since weather records have been kept for the Knysna area, and this had dried out the vegetation.

Secondly, a proliferation of alien vegetation had increased the fuel load, and many of these alien trees were

actually dying because of the drought.

Thirdly, the closure of the Brenton-on-Sea garden waste disposal site had meant that residents were deterred from cutting woody plants on their plots.

Fourthly, peak daytime temperatures had been up in the mid-thirties for a few days before the fire, as a result of a strong berg wind (from the north). And finally an incredibly strong westerly gale gusting at up to 100 km/hr rapidly brought a fire which had ignited in the Karatara area to the Brenton peninsula, where firefighters became helpless to stop it as it was able to jump fire breaks and wide roads.

 

Adult female Brenton Blue

General view of the BBBR after the fire

Candlewood tree (Pterocelastrus tricuspidatus) surviving after the fire

 

The effect on the Brenton Blue butterfly of such a severe fire is not known, although it is believed by butterfly experts that it has adaptations which should enable it to survive such a fire. The larvae and pupae of the butterfly are underground at this time of year, tended by host ants Camponotus baynei, and feed on the rootstocks of the host plant. It is believed from studies on other butterflies with similar life cycles that the larvae and pupae have the capacity to remain in a diapausal state for several years until surface conditions are again favourable. The host plant itself should be able to recover quite quickly, being a resprouter which sends out new shoots from the rootstock. New host plants will also be recruited from seeds buried in the soil, whose germination is stimulated by the heat and smoke. The host plants tend to be concentrated on the shady sides of candlewood trees and the survival and regrowth of these trees will be critical. The effect on the host ants is at this stage unknown, although those that are underground tending the larvae may be able to survive on the nutritious fluid exuded by the dorsal nectar organ of the larvae.

 

A research project is being initiated which will involve a number of scientists and institutions, including ecologists, lepidopterists, botanists and myrmecologists (ant experts). These scientists will track and study the succession processes followed by the vegetation, ant communities and of course the Brenton Blue butterfly itself. To facilitate and encourage the butterfly’s recovery another site nearby, which was much less effected by the fire and has a good population of the host plants, is being prepared to be a refuge to receive any adult butterflies that emerge, if there has been insufficient time for the host plants and the ant communities to recover at the reserve itself.

 

Considerable funding (at least R100 000) will be needed to sustain such a research project, probablyover a few years, and nature lovers throughout South Africa and indeed the world are urged to make donations to the Brenton Blue Trust, either via its website www.brentonbluetrust.co.za or by making a direct deposit into its Nedbank account number 2089033681 (branch code 108914), using as a reference “KNYSNAFIRE”. Funds donated with this reference will be ring-fenced for this specific research project.

Brenton Blue Trustees

22nd June 2017

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