Cane toads have reached the Kimberley and there is no sign that their conquest is nearing completion. Their relentless advance across the Top End makes it seem like they are invincible, but we believe that by exploiting the toads’ inability to retain water, we might be able to control its spread. Few, if any toads can survive more than 10 days without water in the dry season.
So, in very dry regions, we may be able to halt their spread by excluding them from permanent water sources. If we manage lots of water sources in the same area (eg, by fencing natural water bodies, or minimising leaks in tank and trough systems that provide water to cattle), we might be able to create a waterless barrier or ‘firebreak’ in the landscape that toads can’t penetrate.
Now this sounds ambitious – where could we manage all permanent water bodies to create a waterless firebreak? Well it just so happens that toads will need to march south towards the Pilbara through an arid corridor where permanent natural water is in short supply. Artificial water points and natural springs dot the corridor, forming a thin strip of suitable toad habitat along the coast. The combination of landscape and climate makes this corridor a potential bottleneck (or choke point) in which to create a barrier.
Tingley R, BL Phillips, M Letnic, GP Brown, R Shine & SJE Baird (2013). Identifying optimal barriers to halt the invasion of cane toads Rhinella marina in arid Australia. Journal of Applied Ecology 50: 129-137.