Did dingo control cause the elimination of kowaris through mesopredator release effects? A response to Wallach and O’Neill (2009)

Did dingo control cause the elimination of kowaris through
mesopredator release effects? A response to Wallach and O’Neill (2009)

Wallach & O'Neill (2009) recently suggested that poison baiting for dingoes (Canis lupus dingo and hybrids) caused the localized extinctions of kowaris (Dasyuroides byrnei) through mesopredator release effects. However, in this paper I briefly highlight some weaknesses in their approach to show that the information presented adds little to our knowledge of dingo-mesopredator or dingo-kowari interactions. Wallach & O'Neill (2009) visited two cattle properties in northeast South Australia once each in the winter of 2007 where they used sand plot activity indices to compare the relative abundance of several carnivore and herbivore species at each site. Observations of dingo howling and scat counts were used as measures of social structure. In line with the mesopredator release hypothesis (Crooks & Soule, 1999), the lethal control of dingoes (usually achieved through 1080 baiting campaigns), followed by abundance increases of mesopredators and herbivores was the suggested mechanism that produced the localized extinction of kowaris at one of the sites. Unfortunately though, the study design suffers from multiple critical weaknesses in the methods applied, considerably limiting its ability to make inferences about dingo populations and ecosystem processes.