Miss Niamh O’Kelly2, Dr Dan Noble2, Dr Ryan Colley3, Dr Alejandro Trujillo Gonzalez1, Dr Ben Croak3, Dr Monica Knipler4, Dr Sarah May5, Dr Elise Furlan1, Dr Bernd Gruber1
1University Of Canberra, , Australia, 2Australian National University, Canberra, Australia, 3ACT Government, Canberra, Australia, 4Department of Climate Change, Energy, the Environment and Water, Queanbeyan, Australia, 5Tidbinbilla Nature Reserve, Canberra, Australia
Biography:
Niamh is an Honours student at the Australian National University
Abstract:
Reliable monitoring is a major barrier to conserving Australia’s grassland earless dragons. The Critically Endangered Canberra grassland earless dragon (Tympanocryptis lineata) is cryptic, occurs at low densities, and is difficult to detect using labour-intensive visual inspections of artificial burrows. We developed and validated a species-specific quantitative PCR environmental DNA (eDNA) assay and tested whether swabbing refuges could provide a more efficient presence–absence monitoring method. The project progressed from assay specificity and sensitivity testing, through controlled enclosure trials to field validation at wild populations. Captive trials showed all burrows sampled immediately and one week after dragon exposure were positive. Detection from tiles declined from 95% immediately after exposure to 67% after one week and 58% after two weeks. Rain and ultraviolet exposure reduced eDNA persistence, whereas storage medium, dragon density and deposition time had little influence. In field trials, dragon DNA was detected in all 24 burrow samples associated with a confirmed sighting. The assay was also positive in 9 of 24 burrows where no dragon was observed, indicating that eDNA can detect recent burrow occupancy missed by visual surveys. Tiles were substantially less reliable. These results support swabbing artificial and natural burrows as a minimally invasive and highly effective method for detecting T. lineata. Incorporating eDNA into monitoring could shift surveillance from repeated low-yield searches for individuals towards standardised site-level presence–absence surveys, allowing more sites to be assessed with less field effort and providing clearer evidence of distributional change. This approach may also be adaptable to other imperilled Tympanocryptis species.