 |
| Pulling together for the Ptunarra BrownPtunarra Brown Butterfly | A co-operative conservation effort between Gunns Limited, the Department of Primary Industries, Parks, Water and Environment, Cradle Coast NRM and community volunteers is helping in the ongoing survival of a threatened butterfly found only in Tasmania.
The rare Ptunarra brown, a small, pretty brown and orange butterfly, is known in just a few areas of the State including parts of the Midlands, Northwest Plains and Central Plateau.
Diminishing habitat and an introduced predator have reduced Ptunarra brown numbers alarmingly in recent years, but action to arrest the slide is underway at the huge Gunns Limited-owned Surrey Hills Estate in north-west Tasmania.
Surrey Hills contains almost 5000 hectares of native grasslands, much of which is perfect habitat for the butterfly and a vital stronghold.
“Gunns staff are carefully managing these sites to protect the insect and more intensive conservation efforts are underway,” says DPIPWE Threatened Species Section Head Phil Bell.
Among these are the catching and translocation of butterflies from sites where they are abundant to sites where they have been lost to see if the species is capable of establishing at new sites, something they appear reluctant to do if there is unsuitable habitat in between.
“Information such as this is very important for their ongoing conservation if we are ever required to implement major translocation programs,” Dr Bell said
“One of the difficulties for the species across the State is their habitat has become quite fragmented.”
The establishment of the feral European Wasp, which is known to eat the butterflies, also poses a significant threat to the species.
"They have the potential to completely eliminate the butterflies at discrete sites," Dr Bell says.
“We have noticed Ptunarra brown numbers have dropped dramatically at some of the sites at Surrey Hills and we are trialling wasp control to see if it helps them recover.
Translocation to areas free of the predator may also help.”
Dr Bell said that Gunns staff had been managing the Surrey Hills sites by setting them aside, managing fire regimes and eliminating stock grazing to promote ongoing conservation of the species.
Gunns Resource Manager Robert Onfray said that Gunns recognises the ecological importance of these areas and maintains the native grasslands as private reserves at a cost of $20,000 a year.
“When you have a threatened species on your land, you have responsibility,” Mr Onfray says. “There is value to the community that we are trying to maintain on this land. It’s vital that we protect the state’s rarest butterfly.”
Mr Onfray said that the wasp threat emerged in the past five years, with considerable wasp activity noticeable in the butterfly colonies, and Gunns had worked with the Department to control the predator.
“Protecting and enhancing white grass communities and maintaining the health and biodiversity of the natural ecosystem by burning is also a high priority to conserve this butterfly,” Mr Onfray says.
The grasslands at Surrey Hills were thought to be regularly burnt by the Aboriginal inhabitants for thousands of years, to enable through travel and to concentrate game there. European graziers continued the practice to encourage “green pick” for their sheep and cattle.
| |
