Cane toads (Rhinella marina) in south-western Queensland: invasion front, spread and how Cooper Creek geomorphology could enable invasion into north-eastern South Australia

摘要

The invasion of northern Australia by the poisonous cane toad is well recognised, as is its devastating impacts on numerous local native species. However, there is little recognition that the toads are spreading into south-western Queensland. Utilising local knowledge, a limited survey was undertaken within the Cooper Creek catchment to locate the invasion front. Dispersal during 2010-11 floods has established cane toads as far south as Jundah. Integrating this information with landform mapping indicates that cane toad invasion can continue south-west down the Cooper Creek. Though arid, Cooper Creek's geomorphology renders it partially independent of local climate, and permanent and semipermanent waterholes (including RAMSAR-listed wetlands) are found downstream from Windorah and into the Strzelecki Desert. Natural landforms provide potential daytime shelter and breeding sites, and additional suitable habitat created by human activity is also widespread. Even unsuccessful attempts at breeding may be detrimental to regional ecology, especially fish populations, at critical stages of their boom/bust cycle. We conclude that there is no reason why cane toads cannot penetrate further down the Cooper Creek, threatening wetlands in north-eastern South Australia. Published models of cane toad expansion, which conclude that north-eastern South Australia is too dry for cane toad populations to establish, are based on climatic parameters that significantly under-represent true habitat availability.