Ecosystems from the tropics to the Antarctic are collapsing, scientists warn
Eminent scientists warn that key ecosystems around Australia and Antarctica are collapsing, and have called for a three-step framework to fight the resulting irreversible damage.
The warning and the proposed framework to remedy the crisis is outlined in a report by 38 Australian, UK and US scientists from universities and government agencies, published today in the international journal Global Change Biology.
Professor Carla Sgro from the Monash University School of Biological Sciences was one of the Australian contributors to the report.
“This important body of work documents the collapse of some of Australia’s most iconic ecosystems due to human-induced global change,” Professor Sgro said.
“The report is significant because it highlights the fact that global change is happening now, in Australia,” she said.
“Some of our most iconic ecosystems are threatened with partial if not total collapse,
“The report outlines a framework for identifying ecosystems threatened by collapse which will enable better management of threatened areas.”
Lead author, Dr Dana Bergstrom from the Australian Antarctic Division, said the report emerged from a conference inspired by her ecological research in polar environments.
“I was seeing unbelievably rapid, widespread dieback in the alpine tundra of World Heritage-listed Macquarie Island and started wondering if this was happening elsewhere,” Dr Bergstrom said.
“With my colleagues from the Australian Antarctic Division and the University of Queensland we organised a national conference and workshop on ‘Ecological Surprises and Rapid Collapse of Ecosystems in a Changing World’, with support from the Australian Academy of Sciences.”
The resulting paper and extensive case studies examine the current state and recent trajectories of 19 marine and terrestrial ecosystems across all Australian states, spanning 58° of latitude from coral reefs to Antarctica. Findings include:
- Ecosystem collapse (defined as potentially irreversible change to ecosystem structure, composition and function) is occurring now in 19 case studies. This conclusion is supported by empirical evidence, rather than modelled predictions.
- No ecosystems have collapsed across their entire range, but for all case studies there is evidence of local collapse.
- The 19 ecosystems include the Great Barrier Reef, mangroves in the Gulf of Carpentaria, the arid zone of central Australia, Shark Bay seagrass beds in Western Australia, Great Southern Reef kelp forests, Gondwanan conifer forests of Tasmania, Mountain Ash forest in Victoria, and moss beds of East Antarctica.
- Drivers of ecosystem collapse are pressures from global climate change and regional human impacts, categorised as chronic ‘presses’ (eg. changes in temperature and precipitation, land clearing) or acute ‘pulses’ (eg. heatwaves, storms, fires and pollution after storms).
The paper recommends a new ‘3As’ framework to guide decision-making about actions to combat irreversible damage:
- Awareness of the importance of the ecosystem and the need for its protection;
- Anticipation of the risks from current and future pressures
- Action on reducing the pressures to avoid or lessen their impacts
The scientific team concluded that in the near future, even apparently resilient ecosystems are likely to suffer collapse as the intensity and frequency of pressures increase.
"Anticipating and preparing for future change is necessary for most ecosystems, unless we are willing to accept a high risk of loss,” Dr Bergstrom said.
"Protecting the iconic ecosystems we have highlighted is not just for the animals and plants that live there. Our economic livelihoods, and therefore ultimately our survival, are intimately connected to the natural world.”