Ecology, behaviour and citizen science of Murray River turtles: implications for future conservation and management

Abstract

Two of the three turtle species inhabiting the Murray River, Emydura macquarii and Chelodina longicollis, have declined since the 1970s, whilst C. expansa is rare. As much of the ecology of these turtles and their threats are poorly understood, a comprehensive conservation plan is yet to be drafted. Here, I describe a threat to turtles, investigate aspects of their ecology and behaviour, and evaluate methods for public engagement in turtle conservation. These areas are critical for the design of an effective management plan. In Chapter 2, I describe mortality on roads using data collected via citizen science, and show that C. longicollis is most at risk on multiple-lane highways during their nesting season and after rain. I propose testing road signs, eco-passages and artificial nesting grounds to address this issue. In Chapter 3, I evaluate the consequences of the decline of all three species by quantifying their scavenging role, and show that they are key scavengers that positively affect water quality. Hence, areas with few or no turtles are likely to be most affected by unchecked carrion decay, highlighting the need to address the turtle decline. Headstarting hatchlings may be an effective conservation technique. In Chapter 4, I test whether hatchling E. macquarii associate with aquatic vegetation, and whether captivity affects their behaviour and short-term survival, to inform a headstarting plan. I conclude that E. macquarii hatchlings should be released at hatching in areas with abundant aquatic vegetation. In Chapter 5, I show that skills and knowledge gains after participating in the citizen science project TurtleSAT are associated with behavioural and attitudinal changes that may be beneficial for turtle conservation. This thesis justifies the conservation of the turtles of the Murray River, informs a future conservation plan, and provides an example approach for other poorly known species that are likely to play key roles in their ecosystem functioning.