A recent article paints a bleak future for this butterfly—and, by implication, for its fellow rarity, the Dullstroom Blue.
Dullstroom Blue (formerly Warren’s Blue)–endemic to Verloren Valei (Photograph: Justin Bode)
A recent article in Metamorphosis, the journal of the Lepidopterists’ Society of Africa (LepSoc), David Edge looks at the history of the famous Brenton Blue butterfly, and its uncertain future. Like the Brenton Blue, the Dullstroom Blue (formerly Warren’s Blue) is found only in a certain area—in this case, Verloren Valei and environs. The devastating Knysna fire of 2017 burnt the entire reserve, and it seems doubtful that the Brenton Blue has survived.
The Dullstroom Blue is similarly exposed to what one might call “habitat risk”. This fact again emphasises the importance of protecting places like Verloren Valei and ensuring that they are as protected as possible against runaway fires. That can only be done by giving the reserve management the tools they need to undertake the regular, rotational burning programme needed to contain runaway fires.
Read our earlier article, “Warren Blue’s last stand” for more about the Dullstroom Blue.
The Metamorphosis article’s Abstract follows:
The Brenton Blue butterfly became nationally famous in the 1990s when the Lepidopterists’ Society of Africa (LSA) launched a campaign to prevent its imminent extinction, because of the development of a luxury housing estate at Brenton-on-Sea on the southern coast of South Africa. This campaign gained support from national and international NGOs as well as the South African public and pressure mounted on the National Government to intervene. Eventually the Brenton Blue Butterfly Reserve (BBBR) was established to protect the butterfly in 1997, with the status of a “special nature reserve”. An intensive research project was conducted from 2000–2005, which uncovered the butterfly’s unusual ecological requirements, including the caterpillar’s habit of feeding on the rootstock of its host plant Indigofera erecta under the protection of Camponotus baynei ants. The vegetation composition and dynamics, the biology of the host plant, the ant community and the population dynamics of the butterfly were also outcomes of this research. This facilitated the development of a reserve management programme, which for over 20 years seemed to ensure the butterfly’s survival. Fire exclusion was practiced because of the risk to the host ants, which nest in dead wood on the surface. Despite these precautions, during the unprecedented Knysna fire in June 2017 the entire butterfly reserve was burnt, and even though some butterflies emerged in November 2017, these were the last ones seen at the BBBR.
