Fate of famous Brenton Blue butterfly
A question on many resident’s lips after the disaster that hit the Greater Knysna is: “Will our butterfly survive the fire – will she emerge from the ashes, or is this the end of one of the icons of our town?”
According to a statement released by the trustees of the Brenton Blue on June 22 the Knysna fire of June 7 also raged along the Brenton Peninsula, destroying dozens of homes, many in Brenton-on-Sea, location of the famous Brenton Blue Butterfly Reserve (BBBR).
“The 15ha expanded BBBR 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,” read the statement.
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.
Edge said that several factors coincided to produce a fire of this nature.
“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 Brentonon-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/h 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.”
Edge continued by saying that the effect on the Brenton Blue butterfly due to 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,” he said.
According to Edge it is believed from studies on other butterflies with similar life cycles that the larvae and pupae of the Brenton Blue 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,” he said.
The statement from the Brenton Blue trustees also made mention of a research project currently being initiated which will involve a number of scientists and institutions, including ecologists, lepidopterists (a person who studies or collects butterflies and moths), 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,” the statement said.
Considerable funding (at least R100 000) will be needed to sustain such a research project, probably over 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 ringfenced for this specific research project, and so folks, we can but wait in hope.