Earthwatch

A new research project Conserving Koala Country has been established by Earthwatch Australia to look into the deteriorating habitat and tree condition in the Otway Ranges, Victoria.

Dr Desley Whisson a Wildlife and Conservation Biologist from Deakin University says, "so far we've been tracking the movement of 15 koalas (8 females/7 males) at Cape Otway and observed a high density of koalas in the area of up to 16 koalas per hectare".

In many parts of Australia Koala's are in decline and at risk of extinction due to disease, land clearing and drought, however the high density of Koalas is posing a potential issue in The Otways.

Historically Koalas were hunted for their fur and were driven to near extinction. To secure the species in Victoria, koalas were relocated to islands. The resulting populations were then used to restock mainland habitat. This has lead to low genetic diversity of the species in Victoria and has resulted in some high density populations where there are preferred food trees. At Cape Otway, these high density populations are overbrowsing Manna Gum and many trees are dying.

"It's not unusual to see multiple koalas in the one tree in this area, and this is very unusual behaviour for koalas. The manna gum is like chocolate for the koalas", says Dr Whisson.

Although there are a range of different trees in the area including blue gums, the research has so far assessed over 304 trees in total and found significant damage to the manna gum, the preferred browsing tree for Koala's in this area.

During the recent research trip during mating season the research team made up of Earthwatch volunteers recorded vocalisation of the koalas using a songmeter; a device set to record bellows for 5 minutes every hour. Volunteers recorded the number of bellows and whether it's a male or female.

"We found a high number of koalas with young so it looks like a successful breeding year. The koalas are occupying very small home ranges where trees are still in good condition. They obviously don't need to move far to find food or mates. A 3 legged female adult koala was also found, something very unusual to see and particularly for her to have survived to adulthood, " says Dr Whisson.
Volunteers also ventured out at night with a spotlight to search for possums that could also be causing defoliation of trees. They saw lots of koalas but only found possums in one blue gum site.

Richard Gilmore Earthwatch Executive Director says "It's great to be able to be able to support research aimed at protecting the habitat of the iconic koala, and at the same time involve the general public in such a hands-on and interesting way."