Endangered southern hairy-nosed wombats could be dying because drought and weed infestation is forcing the marsupials to eat toxic invasive plants, according to new research.
Scientists from the University of Adelaide, the University of Queensland and Aberystwyth University performed DNA analyses on wombat scat, validated against diet reconstructions of captive and autopsied animals and a study of wombat-grazed sites.
Chemical analysis revealed a summer diet that is often dominated by the brassica called Wards weed, (Carrichtera annua). This invasive weed contains high levels of bitter-tasting glucosinolates which are toxic in high doses to animals.
Lead researcher Prof Mike Wilkinson said habitat degradation and droughts severely restrict feeding options for the wombats, which forage locally rather than long-range.
“The most degraded site also contained most individuals showing signs of glucosinolate poisoning. We infer that dietary poisoning through the ingestion of alien invasives may have contributed to the recent population crashes in the region,” he said.
In sites with a variety of plants, the wombats appeared to manage glucosinolate intake, he said, adding: “Recovery of the most affected populations may still be possible but may require effective Carrichtera management and interim supplementary feeding during periods of summer drought.”