Farm Table says:
Cane Toads on Cowpats: Commercial Livestock Production Facilitates Toad Invasion in Tropical Australia
What is the problem?
Cane toads have spread into hotter and drier regions of Australia. They are poisonous to anything that tries to eat it, including dogs. They disrupt native ecosystems and can cause pasture degradation by eating dung beetles.
Researchers from the University of Sydney noticed that cane toads are attracted to cow pats and wanted to confirm that this is because cowpats provide moisture, warmth and food. This would mean that grazing systems aid in the invasive spread of cane toads.
What did the research involve?
- Field surveys counted the number of cane toads (26) and cowpats (117) in 11 sites, measuring the distance between each toad to cowpat and comparing these distances with computer randomized placements.
- Construction of agar based toad replicas to measure water lost by the toad on bare soil, cowpats, and grass overnight.
- Use of infra-red thermometers to measure ground temperature, cowpat temperature, grass temperature, and cane toad body temperature
- Placed cane toads in enclosures with cowpats, dirt mound, or neither to measure amount of insects attracted to and consequently consumed, in each ground covering.
What were the key findings?
- 17 of 26 cane toads were found sitting on top of cowpats, confirming it is not a random choice for the cane toad. The remaining cane toads were found about 1m from a cow pat. Randomized placements would put the cane toads about 3m from a cow pat.
- Cowpats provided a substrate that was middleground in both temperature and water loss. Bare ground, although the warmest, caused the greatest water loss for the cane toads. Grass areas caused the least water loss but were the coldest.
- The best fed cane toads were ones in an enclosure with cowpats as the dung beetles provided more food than all other insects.
Cowpats provide a balanced microhabitat for cane toads and most importantly a consistent food source from dung beetles. This is bad for pastoral farms as less dung beetles means a longer time for cow patties to be returned to the soil and poorer quality pastures.
This paper was summarised by Mia Courtney (Agricultural Sciences Student – La Trobe University) and reviewed by Nickala Best (PhD Student – La Trobe University). Learn more about Mia and Nickala here.