27 September 2012
Scientists at the South Australian Museum say a spectacular native bee could become extinct if better environmental management practices are not developed.
The Green Carpenter Bee (Xylocopa (Lestis)) disappeared from the South Australian mainland in the first half of last century and can now only be found on Kangaroo Island and some parts of the east coast of Australia.
Museum Honorary Research Associate Dr Remko Leijs says the devastating bushfires on Kangaroo Island in 2007 drastically threatened the native habitat of the bee, which nests in dead flowering stalks of grass trees and dead banksia branches that are affected by dry rot.
Before the fires, the largest number of nests was found in Flinders Chase National Park.
"I became very worried when I visited Kangaroo Island last year. I started looking for the bee nests and I didn't find them at spots where I usually would find a nest within ten minutes. This time at several spots, I looked for two hours and didn't find any nests," he says.
Researchers have applied for about $19,000 Federal money to conduct a survey of the Green Carpenter Bee at Flinders Chase National Park and surrounding areas. The program would also involve the community and use volunteers, who would inspect flowering stalks for bee nests.
Dr Leijs says the bee could become extinct unless fuel reduction burns on Kangaroo Island are carefully planned and managed. The grass trees bloom heavily after a fire. After about two years, the stalks become suitable for the bees to nest in. Another two years later, the stalks fall to the ground and the bees have to move on to a new home.
"So the bees actually need small-scale controlled bushfires, one small spot in a certain place and then the next year, another spot," says Dr Leijs.
In 2007, Flinders Chase National Park was nearly completely burnt. This would have decimated the bee population. Now, the park needs to be recolonised from the surrounding pockets that were not burnt.
Unfortunately for several of these remaining pockets, fuel reduction burns have been planned in the near future. These burns could be the final blow for the Green Carpenter Bee population on Kangaroo Island.
"We need to find out how many bees are still left in Flinders Chase and in the surrounding areas, and this should be assessed before any further fuel reduction burns of native vegetation are done. If the bees are still there, we should investigate the health of the population. If it is suffering we may need to reintroduce them to the park," says Dr Leijs.
Scientists want to use their expertise to stop yet another native Australian animal from becoming extinct.
"The Green Carpenter Bee is the largest native bee species in South Australia. It is a beautiful and iconic species, and we don't want to lose it. The ecosystem would also lose an important player as the bee pollinates a number of plant species that are not pollinated by honeybees."
Dr Leijs hopes the grant will help work out ways to better manage fires on the island, to maintain healthy ecosystems and to protect this valuable, iridescent creature.
The Green Carpenter Bee is solitary – it doesn't live in a hive but on its own or with one relative. The bees mate in spring each year and females produce a single generation per year. They stay in the stalks until the following spring.