Christmas Island is truly like nowhere else in the world, but the island’s highly endemic fauna is under pressure. Four species of mammal have gone extinct since human settlement, including the presumed recent loss in 2012 of the endemic pipistrelle bat. And it’s not just the mammals that have suffered. Since 1980, Christmas Island has also witnessed catastrophic declines in reptile numbers, with five of the six native reptiles currently on the verge of extinction. Taken together, this is believed to be one of the largest reptile decline problems that Australia has ever faced.
The causes of these reptile declines are unknown, but the accidental introduction of invasive species has had devastating effects on many Christmas Island animals. Park managers suspect that the reptile declines have resulted from combined pressures from a range of invasive species, including cats, rats and yellow crazy ants. Two other highly invasive species: the Indian wolf snake (Lycodon capucinus) and the giant centipede (Scolopendra subspinipes), have filled the island’s vacant ecological niche of ‘small-reptile predator’ with potentially devastating consequences for the endemic reptiles of Christmas Island which have no experience with such predators.
Melissa Wynn’s research on Christmas Island aims to identify key threatening processes acting upon the endangered, endemic reptiles and develop ways to effectively target our investment in management to support future reintroductions and mitigate the risk of further decline in the Christmas Island giant gecko. This research strengthens existing links between EDG scientists and Parks Australia building on collaborations on Christmas Island and in other Commonwealth national parks.
Currently Melissa is working with experts from around the country to identify all the potential threats causing reptile declines on Christmas Island and to model the costs, benefits and constraints of all available management actions. These models will form a decision framework, identifying what new information would be of most value to inform research priorities in the field.