Long-term changes in the mammal fauna of logged, coastal forests near Bega, New South Wales, detected by analysis of dog and fox scats.

Abstract

In 1996, a study was undertaken to identify the mammals in Mumbulla State Forest near Bega on the south coast of New South Wales through the collection of dog and fox scats in the area. A total of 1121 scats was collected. The objective was to assess the changes in mammal fauna since 1981 when the first detailed analysis of predator scats was made after the forest was first logged for woodchips and sawlogs under the Eden woodchip agreement. The most notable change between the two surveys was a decrease in the canid diet of large mammals such as swamp wallaby and red-necked wallaby and the rabbit, and an increase of smaller mammals such as bush rat, long-nosed potoroo, common ringtail possum and dusky antechinus. The regrowth of the forest following logging, particularly of the understorey, increased available habitat for some species, such as the long-nosed potoroo. The shift to the smaller species was most pronounced in the diet of foxes. The decrease of rabbit in the canid diet was consistent with its relative abundance on adjacent farmland. The extensive 1996 scat collection also provided an opportunity to examine predator movements. Non-poisoned baits containing coloured markers were placed along the forest roads to determine how far dogs and foxes range between feeding and defecation. Of the marked scats collected in the forest, 67 % were found within 2 km and 94 % were found within 5 km of the bait station. These data will assist future researchers to find the locations of target species by narrowing the potential area to be searched. The primary finding of this study, namely that the mammal composition of the forest changed markedly between the two surveys, highlights the need to sample a forest through time to reveal the forest’s full ecological picture. It can be predicted that the mammal fauna composition will change again following the next logging cycle.