Dingoes have greater suppressive effect on fox populations than poisoning campaigns

Abstract

The mesopredator release hypothesis predicts that abundance of smaller predators should increase in the absence of larger predators due to release from direct killing and competition. However, the effects of top predators on mesopredators are unlikely to operate in isolation but interact with other factors such as primary productivity of the landscape and human activities. We investigate factors influencing activity indices of a top predator (dingo) and an introduced mesopredator (red fox) in forests of south-eastern Australia. We used generalised linear models to investigate the effects that net primary productivity, proximity to freehold land and poison baiting campaigns directed at dingoes had on fox and dingo activity. Baiting was the best predictor of activity for both dingoes and foxes. Dingo activity was variable but typically lower at baited sites. Fox activity varied within a lower range at a majority of sites compared to the dingo but was typically higher at the baited sites. Positive responses of foxes to dingo control are consistent with the mesopredator release hypothesis and suggest in this region dingoes may have greater suppressive effect on fox populations than poisoning campaigns directed towards dingoes. Our results suggest that removal of dingoes may be counter-productive for biodiversity conservation because it may lead to higher activity of foxes.