In the South Australian River Murray, infrastructure is being increasingly used to deliver water for the environment in an already highly regulated system. While these new blocking banks and regulators can deliver much needed water to water-deficient floodplains, they also create potentially significant barriers to aquatic fauna movement. Fishways are usually incorporated into infrastructure designs but what about the turtles who also perform key ecosystem functions between the river channel and the floodplains?
Twenty Eastern long-necked turtles were captured on the Pike River Floodplain, South Australia and fitted with dual VHF-UHF transmitters and their movements recorded over a 14 month period from September 2022 to November 2023. Unintentionally, this period also happened to include the largest flood event in the River Murray since 1956 which completely overtopped the infrastructure for a period of the study. Despite this, the blocking bank was crossed an average of 5.2 times per individual with more crossings occurring during the pre-flood period than during and after it. Whilst the movement was more regular pre-flood, the range of their movement increased with the flood and this study captured record individual home ranges for Eastern long-necked turtles, orders of magnitudes greater than other published studies.