Ecological roles of rabbit, bettong and bilby warrens in arid Australia

Burrows created by other organisms provide important refugia for many vertebrates and invertebrates. With severe range declines of most of Australia's burrowing mammals, the introduced European rabbit may have replaced the role of native burrowers. The vertebrate and invertebrate fauna using the warrens of the native burrowing bettong and greater bilby were compared with fauna using warrens of the introduced European rabbit and control sites without active warrens in arid South Australia. Echidnas, broad-banded sandswimmers, hemipterans and coleopterans, particularly Brises caraboides, revealed a preference for warrens over sites without warrens. Iridomryrmex sp. E (rufoniger gp.) was recorded at significantly higher abundance at bettong rather than rabbit warrens and Melophorus ants apparently benefited from the bare ground around warrens of both native burrowers and rabbits. Identification of small mammal preferences for different warren types was confounded by low predation rates inside the Arid Recovery Reserve, where cats and foxes had been exterminated to allow reintroduction of native burrowers. Due to the widespread use of the below ground and surface features of warrens by commensal native vertebrates and invertebrates, consideration should be given to reintroducing native burrowers following the removal of rabbits in arid Australia.