Conserving the Endangered Western Spiny-tailed Skink, and a Critically Endangered Language

Main Club February 2023

Our speaker was Dr Holly Bradley, an ecologist with a keen interest in conserving and managing threatened species and bringing Western science and traditional knowledge together. Holly has been a DRB Nats’ Club member for many years. For her honours degree, she studied Honey Possums – work that has helped plan controlled burning. Holly showed us a picture of her holding a tiny Honey Possum in one hand. In Costa Rica, she studied sloths and whether returning rehabilitated sloths to the wild could be successful.

For her PhD in 2022, through the Centre for Minesite Rehabilitation at Curtin University, Holly studied the ecology of a Bobtail-sized reptile, the Western Spiny-tailed Skink, Egernia stokesii badia (Meelyu in the Badimia Yamatji dialect). She focused on its conservation and how to successfully translocate them back into areas of their former range where they had been disrupted by mining activity. (No attempts so far have been successful.) This is an important part of re-establishing a spiritual (totemic) connection to the Country for the Badimia people, who have seen the numbers of Meelyu diminish. In her study area, the open eucalypt woodlands of the Midwest and Northern Wheatbelt, the threats to this species, which live in colonies in log piles, include grazing, predation, firewood collection and fire.

Holly began by doing an extensive global review of the successes and failures of translocation – their goals, management techniques, and which ones resulted in a self-sustaining population. (Only 20% were successful!) To study predator-prey dynamics, she created plasticine models of the skink. Peck marks were identified, showing what species had attacked the models. She observed which predatory birds were present around the log piles where the skinks occurred. And she used camera traps. Cats were observed taking skinks, but ravens sought them out specifically, and there were more ravens near log piles with skinks. Significantly, there were more corvids at log piles close to the landfill sites – a lesson for mining companies about rubbish disposal.

Holly used LIDAR to find the skinks preferred habitat. She found they liked a pile of 2-3 longish logs without much canopy cover (fewer perches for birds). Then she looked at how their food preferences changed with age, using scat analysis. The young eat mainly grasshoppers and then become omnivorous and opportunistic – mainly daisies, other plants, and some insects. One problem with translocation is that the skinks exhibit homing behaviour and run away. An obvious solution is to fence the area, but corvids would sit on the fence, ready to swoop, and the skinks would be trapped!

Trials have yet to be done, but Holly identified research needs. These are to find their home range, dispersal capacity, stress mitigation techniques and thermoregulatory niche and develop captive breeding methods and long-term monitoring.

In line with her interest in respectfully blending Western and traditional Indigenous ecological knowledge, known as Right Way Science, Holly’s thesis will be translated into Badimia. She is writing a bilingual children’s book called Milly the Meelyu.

Mike Gregson