A wildlife trust has found the Wimmera, in Victoria's west, is home to Australia's largest population of a tiny but critically endangered butterfly.
Elaine Bayes, an ecologist with Wetland Revival Trust has worked to protect the Eltham copper butterfly since 2009 and was surprised 500 individuals were found — almost ten times more abundant in Gerang Gerung wildlife reserves, than the next largest habitat.
"Eltham copper butterfly numbers at the two very small known populations in the Wimmera were at much higher densities than in north central Victoria where we had been searching."
First discovered in 1938 in Eltham, the Eltham copper butterfly with its strikingly orange wings was thought to be extinct in the 1950s.
Besides Melbourne, they were also found in north central Victoria in 2001 but population numbers remained low because their habitats had become quite small because of urban subdivision and land clearing.
Ms Bayes said the butterflies had never been mapped before but she knew they were found with a plant called sweet bursaria (bursaria spinosa) and mapped their locations.
"They're actually really hard to see which is another reason they're probably rare," she said.
"They can sit on a 10-cent coin with a wingspan of 2.5 centimetres."
"When they've got their wings closed, they disappear … they're very dull underneath.
"But when they open their wings and bask in the sun then you get to see this coppery gold centre of their wings.
"Looking for the plant is much easier than looking for the butterfly."
Numerous threats
Ms Bayes said these butterflies were extremely vulnerable to environmental change because they depended on a single plant species for food and ant species to protect their young from predators.
"The Eltham copper is particularly fussy which isn't an advantage in the longevity of things."
She said the given they were only found with pockets of sweet bursaria, the butterflies have became quite environmentally isolated, reducing the genetic diversity in their gene pool.
Another threat was habitat loss, particularly in the Wimmera where there has been abundant historical land clearing.
Ms Bayes said the trust's mission was to build local capacity, ownership and awareness of the species as the butterflies were found by locals.
She also developed a guide on how to find and identify them and encouraged Wimmera citizen scientists who had sweet bursaria in their surrounds to look for the butterflies and log them online.
"All these remaining little bits of remnants have all got treasures in them."
"It's really about protecting remnants and finding out what treasures you've got in them or looking for them on your property."
