Thesis
Influence of temperature and habitat fragmentation on the movement and activity of a freshwater turtle (Chelodina oblonga)
Honours, Murdoch University
2023
Abstract
Freshwater turtles are one of the most threatened groups of fauna, with over 60% of species worldwide listed as threatened or worse on the IUCN Red list. However, there is a paucity of information on the fine-scale movement ecology and activity of freshwater turtles, including how they may respond to shifting environmental variables such as temperature and salinity, as well as the impacts of aquatic infrastructure on species living in urban habitats. This scarcity of information then hinders the formation of robust conservation measures. This study aimed to assess the applicability of using biologgers to study the behavioural ecology of the southwestern snake-necked turtle (Chelodina oblonga – previously C. colliei), a species endemic to south-western Australia and under threat from climate change and anthropogenic activities. It further aimed to use biologger and telemetry data to quantify the effect of habitat fragmentation and temperature on the movement and activity of the species. Twenty-three C. oblonga were fitted with acceleration biologgers and VHF radio tags upstream (non-tidal habitat) and downstream (tidal habitat) of a weir within an urban riverine system. Tagged turtles were tracked using radio-telemetry to determine movement between habitats, including weir crossings. Basking, nesting, and diving behaviours were identified within the accelerometer dataset for the first time in this species. Turtle activity was highly variable, and was significantly influenced by time of day, sex, temperature, and habitat, suggesting this species’ responses to environmental changes may prove to have a high degree of plasticity. Turtles were found to be capable of crossing the weir, however, this was rarely recorded (6% of tagged turtles), and turtles tagged downstream of the weir more frequently migrated to a nearby freshwater lake rather than pass upstream of the weir. This study therefore (1) confirms biologgers are a valuable tool for the collection of fine-scale data on freshwater turtles, (2) suggests that the weir confers some degree of habitat fragmentation for C. oblonga, and (3) presents an initial insight into how habitat fragmentation and temperature affect activity and behaviour in this species.
Details
- Title
- Influence of temperature and habitat fragmentation on the movement and activity of a freshwater turtle (Chelodina oblonga)
- Authors/Creators
- Kiera A Gordon
- Contributors
- Karissa Lear (Supervisor) - Murdoch University, Centre for Sustainable Aquatic EcosystemsStephen Beatty (Supervisor) - Murdoch University, Centre for Sustainable Aquatic EcosystemsAnthony Santoro (Supervisor) - Murdoch University, Harry Butler InstituteJane Chambers (Supervisor) - Environmental and Conservation Science, Murdoch University
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005639570007891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Thesis
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