Authors: Saskia Beudel (Adjunct Associate Professor, Centre for Creative & Cultural Research, University of Canberra) and Anke Maria Hoefer (Frogwatch)
This exciting ACT Government-funded project studies the impact of climate change on phenology, or seasonal behaviour, in frogs of the Australian national capital.
Most frogs only call during the mating season, and this is triggered by temperature and rainfall. Different species mate at different times and volunteers record the onset of mating calls from local species that are winter breeders (Whistling Tree Frog and Common Eastern Froglet), early and mid-spring breeders (Spotted Grass Frog, Plains Froglet, Striped Marsh Frog and Smooth Toadlet), and late spring to summer breeders (Eastern Banjo Frog and Peron’s Tree Frog).
Why frogs? Frogs are known as an ‘indicator species’ for water quality and local ecosystem health. With their permeable, membranous skin, through which respiratory gases and water can pass, and their shell-less eggs laid in water, they are sensitive to even low concentrations of pollutants in water and soils. In this study, frogs give a different kind of warning – as they begin calling earlier in the season, they reveal and give voice to the warming climate we now all inhabit.
The project is fortunate enough to be able to build upon counts of calling frogs by ecologist Will Osborne during the 1980s and 1990s in the Canberra region. Effects of climate change can be incremental and non-linear, being most obvious to us through the increase of extreme events. These kind of changes can be difficult to record in the short term. With this in mind, the Frogwatch project builds on Osborne’s historical data along with the Frogwatch Climate Change data to chart changing trends.
A preliminary comparison reveals that the breeding season of some local frog species might be commencing several weeks earlier than 40 years ago. The in-depth analysis of 4 years of weekly monitoring will commence in early 2019 and the findings are eagerly awaited by a range of stakeholders, including our very dedicated volunteers. Being involved in this project provided them with a rare and much appreciated opportunity to take part in a hands-on climate change study in our local environment.
Climate change volunteer in action. Photo: Sharon Koh