Wetlands are among the ecosystems most vulnerable to climate change but, up until now, predicting exactly how they will respond has been difficult.
New research led by Dr Dave Deane is helping to identify the threshold at which wetland ecosystems begin to shift, and even collapse, because of climate change.
“Freshwater ecosystems such as wetlands, rivers and lakes rely on a delicate balance between water coming in, such as through rainfall, and water going out, through evaporation, human use and so on,” Dr Deane explains.
“Climate change will obviously affect this balance, but the question is – by how much?”
With a quarter of freshwater-dependent animal species already at risk of extinction, Dr Deane’s work aims to predict the magnitude of the changes we will see in our wetland ecosystems in future.
He’s grouping wetland species by their flooding tolerance, using what are known as ‘response curves’ to model how vegetation composition changes as water levels drop.
“Our response curves predicted that once maximum water depth falls more than eight centimetres below ground, wetlands begin transitioning toward upland plant communities,” Dr Deane says. “This is an example of a tipping point, an ecological threshold where the character of the wetland changes dramatically.”
Dr Deane is now working with aquatic botanists across Australia to determine if the thresholds apply to other types of wetlands and regions, with the goal of building predictive tools that combine climate and hydrological projections.
“We’ve installed a network of groundwater and soil moisture sensors in wetlands across Victoria and South Australia,” he says. “Over the next few years, this data will help us sharpen our understanding of how, and when, wetlands may disappear.”
