Leading lake ecologist stresses we must build resilience

Professor David Hamilton

Faced with the threat of more frequent weather events, society must change its land use habits in order to protect our precious waterways from further damage.

That is the view of new Professor David Hamilton who has joined Griffith University’s internationally renowned Australian Rivers Institute, bringing with him years of research and knowledge on lake ecology.

Taking the helm as Deputy Director, Professor Hamilton’s research focuses on algal blooms, nutrients cycles and the use of models for prediction and management of lake ecosystems.

Professor Hamiltonpreviously led a research group at the University of Waikato known as Lake Ecosystem Restoration New Zealand (LERNZ). LERNZ was a ten-year $10 million initiative to identify and remediate threats to lake ecosystems. He said the biggest threats to ecosystems were climate change and diffuse pollution from land use.

“The frequency of the 1 in 100-year storms is likely to double, they’ll be one in 50 years and the cyclones and major weather events we’ve recently seen are almost certainly going to become more frequent,” he said.

“There will be more flooding and ironically enough, more drought.

“The basis of that is as a continent, Australia is going to warm up. That makes it drier on land but at the same time warm air is going to hold more water, so rainfall events are going to be larger and have greater impacts.”

A lake restoration project in New Zealand Professor Hamilton worked on.

Professor Hamilton said ‘non-point source pollution’ — where waterways are polluted by activities across the catchment — was becoming a great challenge.

“What we’re talking about is land use change as well as intensification of existing land uses producing more sediment and nutrients,” he said.

“Agriculture is a major economic driver through food production and its export earnings, but it is also responsible for much of the diffuse pollution to waterways. A major challenge is how to get people to change and reduce diffuse pollution. Practices accepted in the past won’t necessarily be accepted in the future.

“One of the key areas now is going to be building resilience in our catchments. The way we’ve manipulated and cleared land historically has run down resilience and left legacies of sediment and nutrients in waterways.

“These are major challenges looming — how do we stop that transport of material from the upper catchment into a system people really care about like the Great Barrier Reef for example?”

Professor Hamilton said as well as changing behaviour and practices, targeted areas would need to be rehabilitated and engineering approaches undertaken to build wetlands that could intercept water flow downstream.

Professor Hamilton helped set up the Global Lake Ecological Observatory Network (GLEON) in 2004. This group has now grown to more than 700 and involves scientists who use high-tech sensors in lakes to understand, predict and communicate the role and response of lakes in a changing global environment.

He also established New Zealand’s first national multi-institutional lake research program which includes an interactive geospatial platform he hopes can be replicated in Australia. The program links several databases on 3800 lakes greater than one hectare across the country, to provide vital information on their stream networks, soils, weather conditions, water temperature, invasive fish distributions and more.