Can excluding toads from water provide biodiversity benefits for arid Australia?

A project undertaken at the School of Biological, Earth & Environmental Sciences, University of New South Wales, and supervised by Mike Letnic


We are testing a new approach for controlling the impacts of cane toads on native predators. The invasion of cane toads across northern Australia has been an ecological tragedy. Cane toads contain novel toxins that are absent from Australian frogs, and consequently, many predators die after attacking or consuming toads. Populations of goannas, freshwater crocodiles, snakes, and northern quolls have severely declined following the arrival of toads. Toads are now expanding their range into semi-arid regions of the continent, where they pose a serious threat to the persistence of a rich suite of carnivorous reptiles. In arid regions, toads must access standing water to prevent dehydration and survive. Toads use dams created to supply livestock with water as refuges to survive periods of dry conditions and then spread between dams after rain.

Our research has shown that excluding toads from dams can suppress their populations. In this project, we are also comparing whether water storage tanks, used as an alternative to dams, can effectively limit toad numbers and their impacts on a fauna, particularly, goannas. Tanks support fewer toads than dams, because there is less water available for toads to rehydrate.

Collaborators

Jonathan Webb, School of Biological Sciences, University of Sydney
Tim Dempster, School of Zoology, University of Melbourne.
Tim Jessop, School of Zoology, University of Melbourne

References

Letnic M, Webb JK, Jessop TJ, Florance D, Dempster T (2014) Artificial water points facilitate the spread of an invasive vertebrate in arid Australia Journal of Applied Ecology. DOI: 10.1111/1365-2664.12232

Webb, J K; Letnic, M; Jessop, T S and Dempster, T. (2014) Behavioural flexibility allows an invasive vertebrate to survive in a semi-arid environment. Biol. Lett. 10: 20131014.

Jessop, T S; Letnic, M; Webb, J K and Webster, T. (2013) Adrenocortical stress responses influence an invasive vertebrate’s fitness in an extreme environment. Proc R Soc B 280: 20131444

Tingley, R; Phillips, BL; Letnic, M; Brown, GP; Shine, R and Baird, SJE (2012). Identifying optimal barriers to halt the invasion of cane toads Rhinella marina in arid Australia. Journal of Applied Ecology:50, 129-137

 


 
Figure 1. Cane toad with tracking device, at a farm bore.

Figure 2. A water tank, used as a reservoir for storing water for livestock in the Northern Territory. Tanks support fewer toads than dams.

Figure 3. A yellow spotted goanna (Varanus panoptes). Goanna populations have crashed following the arrival of cane toads