Oral Presentation Australian Freshwater Sciences Society Conference 2022

The implications of climate change and urbanisation throughout the lifecycle of a freshwater turtle (#90)

Anthony Santoro 1
  1. Environmental and Conservation Sciences / Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia

Southwestern Australia is undergoing severe climatic drying. Urbanisation of the Swan Coastal Plain has also resulted in the modification or loss of >80% of wetlands. This project investigated how these stressors are affecting survival and recruitment of the endemic, southwestern snake-necked turtle (Chelodina oblonga). The ecology of the different lifecycle stages of the species were monitored over two-years, within a three-wetland chain that had variable hydro-regimes and extents of urban modification. The study used a combination of radio-telemetry, field observations, and citizen science. It revealed that aestivation, rather than migration, was used to survive wetland drying with some individuals aestivating for >581 days. Prolonged aestivation may reduce reproductive output and survival as the drying trend continues in this region. Nesting movements occurred on ~10 days each year and were associated with cold fronts. The projected alteration of front frequency and intensity is likely to disrupt these nesting movements, further reducing recruitment. Chelodina oblonga also selected more natural terrestrial habitats as nest-sites. These habitats are being reduced with urbanisation. Hatchling emergence occurred during autumn and spring and was associated with increased temperature and rainfall. Altered weather patterns may disrupt timing of hatchling emergence affecting survival. Almost 70 females at one wetland were killed during nesting movements by a combination of predators and road-strikes, and over 250 nests were destroyed by predators, placing additional pressure on the turtle population. This study revealed that all stages of C. oblonga’s life-cycle are under threat from urbanisation and climate change. Solutions to many of these threats are urgently required and will be discussed, including an ongoing citizen science project that monitors and protects female turtles and their nests. Projected climate drying and urban development will necessitate ongoing adaptive management to improve the species’ conservation plight.