Turtle Climate Change Resilience

Around the globe, marine turtle species are experiencing serious threats to their survival, mainly due to climate change, marine debris entanglement and terrestrial predation of eggs and hatchlings. The impacts of rising temperature are particularly pertinent in species with temperature-dependent sex determination. It is known that warming temperatures caused by climate change, is affecting the sex ration of marine turtle hatchlings, with more females being born at higher temperatures. The Western Cape of Cape York Peninsula is home to many turtle rookeries, including those for the endangered Olive ridely turtle.

The Western Cape Turtle Threat Abatement Alliance (WCTTAA) is a partnership of on-ground indigenous land and sea owners and managers coordinating marine turtle conservation programs on the Western Cape of Cape York Peninsula. In the past, WCTTAA successfully reduced nest predation on some beaches from 100% to 10%. This project will further protect the Olive ridley population through mitigating not only predation rates, but also the threat of warming temperatures on hatchling sex ratio.

The key long-term goal of this project is to maintain viable local populations and rookeries of Olive ridley and Flatback turtles on Western Cape York. WCTTAA rangers monitor and protect the nests on seven beaches along the Western Cape York area every year during peak nesting season. Each season, Olive ridley nests are covered with nest protection cages to reduce the risk of predation.

It has been successfully shown, that by lowering the temperature in the nest, the number of male hatchlings increases, which will therefore support the Olive ridley turtle population in the long term. Over the next two years, the aim of this project is to equip the cages with shade cloth to lower the temperature of the sand that covers the nest. In addition, temperature data loggers will be installed to record sand temperatures within and near the nest (control site). Monitoring nest temperatures across the western Cape rookeries will provide valuable insights into the protection mechanisms available to bring nest temperatures closer to the pivotal temperature. This will create a more holistic program for managing Olive Ridley rookeries on Cape York Peninsula.