Conserving Koala Country

Conserving Koala Country

Saturday, 24 August 2013

On the brink

We are 'on the brink' in many ways.  The field season is almost upon us, and a lot is about to happen at Cape Otway.  It is definitely time for a blog update.

Our koalas
In May, I captured 15 koalas wearing VHF collars, for health checks and to attach new GPS devices to their collars.  Thanks to some wonderful volunteers (Samantha, Teagan and Lisa), we accomplished this in just two days, and also managed to plant some trees too.  We had to be extra careful and gentle with the girls because most of them had large pouch young.  Claire's joey, one of the first to be born this season, was actually out of the pouch (but hid inside during the catch).

Claire and joey, May 2013

Our catch list was:
Females: Lucie, Claire, Ruby, Buffy, Nelly, Sally, Lison, Bella, Elena (Katrina's dropped her collar).
Males: Ned, Beast, Austin, Stevie, Scarface, and of course, Cranky Frankie (Tony Parker is MIA... AGAIN!)

Bilko, Erik, Al, Dave and Mac were wearing the GPS collars so didn't need to be caught, although we did track them.  Sadly, we found Mac dead.  A week earlier, a small control burn was put through part of the site to help regenerate the Manna Gum.  Mac must have been in the wrong place at the wrong time. 

Since May, Bilko has also departed us.  He was one of my first koalas to be caught at Cape Otway (in 2010), and was looking good in May.  I can only guess that age and his difficulty in obtaining good nutrition caught up with him.  I retrieved and cleaned off his skull - I have never seen such an odd-shaped skull or such a poorly aligned jaw in a koala.  I'm surprised he was able to eat at all.

Bilko's mishappen skull

Bilko in May 2013 - happily feeding

Our trees
On a very sad note, trees at Cape Otway have taken a rapid change for the worse.  The green flush of growth from December - March provided a bit of hope, but with the trees entering a dormant phase over winter, koalas have stripped many of them bare.  Some trees in our site have died and many are barely hanging on.  The koalas have shifted their ranges slightly as a result.  Most of them are sitting in trees that still have some leaf, along the fenceline, while others have moved out into the paddock trees.

Trees in our site take a turn for the worse


The trees we planted (germinated from seed collected by Earthwatchers in April 2012), are looking good, and there are young seedlings emerging in the burnt areas.  I have already started germinating seed (collected by Earthwatchers in February 2013) for trees that can be planted in Autumn 2014.

Mannas are germinating in areas burnt in May

Manna from seed collected in 2012

Plans for the 2013/2014 field season
A focus of our work this summer will be assessing habitats (tree condition, regrowth, etc), and taking action to ensure that our new trees (planted and naturally germinated) have the best chance of survival.

Koala censuses and tree condition assessments will be conducted in all of our sites across Cape Otway (Aire River, Lighthouse, Parker Hill, Bimbi and Bimbi West).

We'll also be doing some behavioural studies to further our understanding of mate selection.  I will be replacing VHF radiocollars with VHF/proximity collars which will record who is near who, and the length of time they stay together.  We suspect that males guard females until the females are in oestrus and receptive, so this will provide detailed and continuous information on that throughout the breeding season.  I will also be deploying some accelerometers for analysis of the frequency of an individual male's bellows during the peak breeding period.  This will provide insight into testosterone cycling as well as mate selection (are females really attracted to the males that bellow the most?).  Some of the catching for these studies will occur during the November Earthwatch trip.

Dave likes to bellow when I'm around

Radiotracking will occur in all trips and help us understand the daily movements of koalas and tree selection, especially with respect to the changes in tree condition.

Scat collection will also feature as an activity.  The nutritional value of koala food can be determined from scat.  We will therefore be able to see if there is a relationship between tree cover decline and koala nutrition.

We will continue with camera trapping in February.  Koalas aren't the only ones using manna gum woodland.  This will tell us what other species are also present, and how they are being affected by the changes in habitat.

So, lots to do, and exciting times ahead.  Alistair will be leading the September trip and I will be leading the November and February ones.  For those of you who will be joining us, THANK YOU in advance.  I hope you have a fun and rewarding experience with us.


If you didn't catch it, ABC Catalyst did an episode on us.  Check it out at ABC Catalyst - Cape Otway koalas and Deakin/Earthwatch research program

And, the study on koala bellows conducted at Cape Otway (lead by Ben Charlton), is now in press and can be accessed at: Koala bellows (Charlton, Whisson and Reby 2013)

No comments:

Post a Comment