Second only to bees as the most important pollinators, the butterfly is considered a critical player in the Australian ecosystem. However, one already threatened and incredibly rare Melbourne species is now finding survival even tougher as its larval numbers fall to the low double digits, as mojo's Dian Lipiarski discovers. 

by DIAN LIPIARSKI

POPULATIONS of the endangered Eltham Copper Butterfly (ECB) appear to have declined significantly over the past few years, and some experts suspect that a warmer climate is to blame.

Larval numbers in the Eltham Western and Eastern reserves have fallen from 204 and 150 larvae in 2008 to only 8 and 17 in 2012, respectively.

This trend has also been seen in Bendigo and Castlemaine butterfly populations. The Eltham Copper Butterfly is listed as endangered under the DSE Advisory List of Threatened Invertebrate Fauna in Victoria 2009 and the Flora and Fauna Guarantee Act 1988.

Andrea Canzano, zoologist from the Eltham Copper Butterfly working group said she was concerned at that a rapidly changing climate may be having an impact.

“One of our theories is that the climate has changed so quickly that the Eltham Copper Butterfly has not been able to cope with the change,” she said.

Additionally, a lack of connectivity between Eltham Copper Butterfly reserves is negatively impacting the butterfly population.

“It’s not like once upon a time where the butterflies were able to move to a different area when there was change in climate. They don’t have that option now of moving to other areas as easily or at all,” she said.

Even though the Eltham Copper Butterfly has become scarce, Professor Tim New, who has been involved in the conservation effort since the butterfly’s rediscovery in 1987, is hopeful.

“There is always hope while people care,” he said.

He said that it is not known if the fall in population is temporary or permanent.

“If temporary, it could be part of a natural cycle in numbers and part of the normal population dynamic,’’ Professor New said.

“We fear though, that the apparently abnormally low numbers this year may reflect some long-lasting environmental change. We don’t know what that would be. But, most likely would seem to be linked with prolonged drought and warm conditions.’’

Weed encroachment is also making it difficult for butterflies to lay their eggs on their host plant, the sweet bursaria.

Due to these issues, the Friends of the Eltham Copper Butterfly have campaigned for years for the conservation of the iconic butterfly. Last year they received a $459,000 grant over four years from the Department of Environment and Primary Industries (DEPI) (formerly the Department of Sustainability and Environment (DSE)) to protect the species’ environment and ensure its survival.

Over the next four years the grant money will be used on ground work projects, monitoring and community awareness. Weeding and thinning programs will be applied along with monitoring programs to ensure sweet bursaria is accessible to butterflies and that the appropriate management for each urban butterfly site is implemented.

According to Nicole Drever, Nillumbik Council Environmental officer, community engagement is fundamental to the butterfly’s survival.

The community engagement project hopes to develop a network of residents who are interested in the ongoing protection of the butterfly and want to educate the community about the conservation efforts. There are also plans for an annual Eltham Copper Butterfly festival to raise awareness and encourage community involvement.

Ms Drever said that since its discovery, the Eltham Copper Butterfly had become incredibly important to the Eltham community acting as a flagship species for invertebrates in the region.

“It is one of the most well known invertebrate conservation cases from Australia in international circles,” Professor New said.

The Eltham Copper Butterfly has been instrumental in promoting awareness of invertebrates and insects–often considered the ‘Cinderellas’ of the animal world.

“There is definitely a moral obligation for council to undertake responsible action as far as is practical to ensure the survival of the butterfly,” Ms Drever said.

“The council is committed to that and we will continue the work indefinitely.’’

Further larval counts in May will be held to guage the health of the population and the next steps needed in management.