Australia is a big continent with low population density, with most of the population living within 50 km of the coast. This has generated a string of high-density city areas, and lower density towns, connected by a network of roads which usually have wide cleared areas to both sides. And it’s this that is so bad for wildlife: it’s not merely that they get killed by vehicles, but also that they are separated from food and shelter sources on the other side of the road, while populations may be fragmented, making them less genetically diverse and hence more vulnerable.
Enter the Australian Research Centre for Urban Ecology at the University of Melbourne, and Monash University. They found that the average lifetime of a squirrel glider along the Hume Freeway near the Victoria/New South Wales border was 1 year, compared to 4 years for those further out. As a result, poles were erected in the median strip in some areas, as well as rope bridges across the road. The poles provide an intermediate stop for gliders, who would otherwise have been unable to glide the whole width of the road at that point. The rope bridges provided an alternative path, as well as a route for mothers with babies.
This joining of two fragmented areas means that the squirrel gliders are able to cross the road in safety, to reach food, shelter, and actual or potential mates, giving some hope to these endangered animals. According to Dr Rodney van der Ree, deputy Director of the Australian Centre for Urban Ecology, these poles and bridges are a temporary measure, to be replaced in the longer term by strategically planted vegetation.
Kylie Soanes, of the University of Melbourne, is watching these poles and rope bridges, to see how useful they are. After a slow start, animals started using both poles and bridges when they needed to cross the road at that point. These animals included not just squirrel gliders, but sugar gliders, ringtail possums, brush-tailed possums, brush-tailed phascogales, and one goanna*.
And while the animals are still less likely to use even the bridges to cross a wide or busy road than a narrower, less-used one, this still represents a practical research project and partial solution that might give these creatures a breathing space. It will be interesting to see further results of this research, so have a look at Kylie Soanes’ blog for more on this and other items.
* I have to add a personal comment here. I’m glad that these measures will also benefit the goannas, because while saving cute furry creatures is always popular, there’s often little love for the scaly ones.