Status of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands of South Australia. 2. Population dynamics

Abstract

The population dynamics of warru (Petrogale lateralis MacDonnell Ranges race) were studied in the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia, in order to inform management and better understand the race’s conservation ecology. Mark–recapture between 2005 and 2010 at the three largest known remaining colonies, followed by POPAN modelling, indicated that population sizes were 23 at New Well and 24 at Alalka in the Musgrave Ranges, and 14 at Kalka in the Tomkinson Ranges. Taking into account recent survey results, the study confirmed that warru are ‘Endangered’ in South Australia. However, there is potential for the recovery of the race, with high average reproductive rates (in the Musgrave Ranges >90% of reproductively active females had pouch young), even sex ratios and relatively high adult survivorship (>75%). Juvenile survival (51%), however, was significantly lower than that of adults. Given that red fox (Vulpes vulpes) numbers are low at these sites, this is possibly due to predation by feral cats (Felis catus), although this needs further investigation. Juvenile survival was also positively correlated with winter rainfall, possibly indicating that access to water is important during the drier winter months. In light of these observations, it is proposed that management of remaining warru colonies focus on cat control and consider providing access to free water during winter, as well as addressing landscapescale threats such as wildfire and the spread of exotic plants.