Managing feral goat impacts by manipulating their access to water in the rangelands

Abstract

Feral goats are a significant threat to biodiversity in Australia. However, goats are also harvested by some landholders for commercial benefit and this can lead to disagreements regarding control techniques. In the rangelands of New South Wales, feral goat distribution is closely linked to artificial watering points (AWP) such as tanks and bores. Previous surveys indicated that goat activity was rare more than 4 km from water. We hypothesised that constructing sections of goat-proof fencing in areas where goats were feeding on National Parks but watering on neighbouring properties, such that they had to travel more than 4 km from the AWP to access the park, would result in a significant decrease in goat abundance in these areas. We tested this hypothesis in Paroo-Darling National Park, Gundabooka State Conservation Area and Gundabooka National Park using changes in index (fresh goat dung groups per 100-m transect). We also measured kangaroo dung and ground cover index changes. Twelve months after the fences were constructed, goat dung significantly declined compared with non-treatment areas and the relationship between distance to water and goat dung broke down at the treatment sites. Kangaroo indices were not affected by the fences. The results for bare ground were the same as for goat dung, with significantly less bare ground and a breakdown in the relationship with distance to water at the treatment sites after the fences were constructed, but this was due to a corresponding increase in litter rather than live vegetation. This technique can be a significant tool for protecting biodiversity from feral goats, without removing the potential for neighbouring landholders to harvest the goats. If strategically used to create zones free of resident goats around the boundaries of conservation reserves, it should increase the effectiveness of other techniques such as trapping, mustering and shooting, by reducing post-control reinvasion. Recognition of access to water as an important management tool should substantially improve our management of feral goats in the rangelands.