Conserving Koala Country

Conserving Koala Country

Tuesday, 4 December 2012

A legendary effort by legendary people

It is an extreme understatement to say that the November team worked hard.  Our achievements include:
·         Koala census completed at 9 sites (including Aire R)
·         160 randomly selected trees in 8 sites assessed for condition
·         21 new trees tagged and measurements recorded
·         28 tagged trees assessed for condition at Bimbi
·         72 tagged trees located and assessed for condition at Aire R
·         22 koalas captured for health assessment and collar check
·         154 locations of radiocollared koalas recorded
·         4 trees collared
·         Lots of laughs!  
A big THANK YOU to my volunteers: Heather, Leigh, Vicki, Dolores, Helen and Louise; and staff: Cass and Vic for this absolutely amazing effort, and for your never-ending enthusiasm and companionship.
The November team
As for our koalas:

Tony Parker - mug shot
Tony Parker lived up to his legendary status.  He dropped his collar on Day 1 of the trip and we didn’t find him until the last day.  He made me climb to catch him and then casually moved into a neighbouring tree just as I got into position.  It was a major effort (for us, not him) to finally get him down the tree. 
Frank is just as feisty as ever and again tried to attack me as soon as he was on the ground.  Dave is doing well and always bellows a greeting and sometimes shows his excitement in ‘other ways’ (use your imagination here). After the excitement of recollaring Banjo in October, he has managed to yet again break his weaklink and is currently MIA.  Claire is also MIA.  Buffy has a joey ‘Willow’ that is extremely cute, and Ruby obviously is ready for another. The whole team was lucky (or perverted?) enough to watch Ruby and Kevin ‘hook up’.  Ruby actually initiated it – Kevin appeared surprised but certainly up to the task.

Ruby’s former joey Benjamin is now apparently independent and perhaps a bit lonely.  He took a liking to Dolores, chased her and started climbing up her leg.  Even after being prised off and released, he still attempted to climb the nearest pair of legs.

Wally and Bruce are my biggest concerns. Wally had a huge abscess on his upper forearm. We didn’t notice it until it burst during handling. It’s typical of a fight wound. He was still able to climb and was observed in the next few days high in the canopy, but he’s lost almost 1kg since we weighed him in October. Bruce is looking battle-weary. No major wounds but his ears are torn and bloody, and he’s lost 1.5kg since October.

The rest are looking good. New recruit Stevie kept us busy guessing where he was going to move to next (he's now down near Lighthouse Rd), and Beast likes the isolated trees between the site and Big Hill.


We also have three new koalas: Cyril, Harry and Sally. The two new boys are wearing new GPS collars (thanks to the Foundation for National Parks and Wildlife).

Sally and her joey
And, as for what it all means….
I'm still wading through all the data but some preliminary analysis tells a pretty grim story for Manna Gum at the Cape.  In April 2011, almost half the trees assessed in the main site (where koalas are being tracked), had a reasonably healthy canopy of >50% cover. Now, less than 5% have >50% cover (Figure 1).
Figure 1. Decline in %trees with >50% canopy cover from April 2011 to November 2012.
If we just look at those trees that we have monitored since April 2011, mean percent. canopy cover has declined from 51% to 33% (Figure 2).
Figure 2. Mean %Canopy Cover of trees monitored since April 2011
This really is no surprise considering that there are around 18 koalas per hectare munching on the trees in the site.
So, what do we do? That is the question that both landholders and the Victorian government is now asking.
Cull? We can’t cull koalas – culling is not permitted under the National Koala Conservation and Management Strategy (and that is not going to change!)
Translocate? It would not be effective to translocate koalas – koalas would just move in from neighbouring areas, and besides, translocation does not always have a happy ending for the translocated animal.
Sterilise? It would not be effective to sterilise koalas – the trees are already struggling and sterilisation takes a long time to act to reduce a population.
Protect and restore habitat? I think this is the only way forward but one that will take a lot of effort and money.  It also won’t ‘solve’ the problem but at least we will save some Manna Gum which can serve as seed trees for future revegetation efforts.

But, what happens to the koalas?  Will they starve as the trees die? Or will they move on in search of better habitat?  I suspect there will be a bit of both.  Some koalas won’t have the energy to move.  They may already be weak from fighting during the breeding season, or may be burdened by joeys.  However, results from our radiotracking show that koalas (both males and females) are able to make long-distance movements.  Some of our koalas have moved several kilometres over a period of days or weeks.  Sometimes, they have spent several days in areas where there are no food trees.  Only time will tell….

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