Does reducing grazing pressure or predation conserve kowaris? A case study at Diamantina National Park

Abstract

Livestock contributes to the decline of many species in Australia. However, they may have less impact in arid environments, where annual plant species dominate. Kowaris (Dasyuroides byrnei), a small carnivorous marsupial, living on Diamantina National Park were monitored to assess the success of ecosystem recovery following a reduction in cattle. Kowaris were found at 10 locations within the study area: five where they had been recorded prior to the area becoming a national park and five ‘new’ locations. No kowaris were found at one of the historical sites. The density was estimated to range from 1 to 2.5 kowaris per square kilometre from 2007 to 2009. The results suggest that the population likely increased following a reduction in grazing pressure. However, a boom in rodents and predators occurred during the study with a corresponding decline in kowari detections. Kowaris have not been detected at any of the study sites since 2012. These results suggest that management of top-down factors as well as bottom-up factors are required to conserve kowaris. The work further highlights the need for replicated, long-term studies if the interactions between complex ecological processes, at a landscape scale, are to be understood so that threatened species, like the kowari, can be managed effectively.