DNA found 22km downstream reveals hidden populations of threatened frogs

In the wet upland streams of Queensland’s Wet Tropics, researchers have discovered a surprising finding using environmental DNA (eDNA). This technique allowed them to detect threatened frog species without seeing or hearing them, sampling water up to 22 km downstream. The study, led by Dr. Cecilia Villacorta-Rath of James Cook University (JCU), confirms that some populations are more widespread and potentially recovering than previously thought.

The chytrid fungus, an aquatic pathogen that attacks frog skin, decimated frog populations in cool wet areas in the late 1970s and 1990s, especially in North Queensland’s Rainforests. The Waterfall Frog and Lacelid Frog were largely extirpated from the uplands by the early 1990s. However, eDNA results show that these frogs are more widespread, appearing in many creeks, including areas not recorded since the chytrid outbreaks.

The Armoured Mistfrog, previously thought to be extinct, was confirmed as the only surviving population in a single location. eDNA sampling is more straightforward and user-friendly, making it accessible to various groups, including Indigenous rangers, government agencies, and citizen scientists. This technique has the potential to monitor a broader range of aquatic wildlife, aiding in conservation efforts.

The research was funded by the Australian Government and published in the journal Conservation Science and Practice.