Abstract
During the late 19th and early 20th centuries, frustrated pastoralists in South Australia, New South Wales and Queensland fenced their properties to stop the Australian dingo (Canis lupus) killing their livestock. Eventually links formed between individual fences, creating a continuous barrier now covering over 5000 km. Known variously as the Dingo Fence ‘Dingo Barrier Fence or ‘Wild Dog Fence it is of wire mesh standing 1.8 in high, with a further 30cm buried. There is a 5 m wide cleared buffer on each side and the entire structure is well maintained. On the New South Wales side of the fence where sheep are the main livestock, dingoes are controlled and numbers are low, whereas on the South Australian side dingoes are tolerated alongside cattle husbandry. Unintentionally, the fence initiated a large-scale experiment, allowing biologists to assess the biological consequences of removing a large predator.
Alan Newsome and his colleagues from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) studied vertebrate abundances on either side of the fence by counting animal tracks at stock watering points. One striking finding was that the introduced predator the red fox (Vulpes vulpes) was present on both sides, but in higher numbers in the absence of dingoes. Dingoes eat foxes and drive them away, explaining the differences in fox numbers across the fence. Foxes threaten several native Australian mammals (see Chapters 2 and 16), including many borrowers and diggers important in soil turnover, nutrient cycling and dispersing plants. It may be that, by regulating fox numbers, dingoes are protecting native fauna that in turn modify the environment to the benefit of many soil organisms.
The case of the Dingo Barrier Fence shows how relationships between organisms determine the range and relative abundance of species.