Protecting species on the move
The key to how coral reefs of the future will look and function—and how to protect them—could lie hidden in their ancient past.
Prof John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland (Coral CoE at UQ) is speaking at the 2019 Coral Reef Futures Symposium in Sydney, today.
Prof Pandolfi studies the life history traits of corals from the Pleistocene—the last interglacial—in a climate that was one to two degrees warmer than now. He says back then many corals moved away from the warmer regions. It's the traits of these past corals that may hold the clues to protect today's corals, which are themselves shifting their distributions in response to global warming.
"We're closer to understanding what makes certain coral species winners or losers," Prof Pandolfi said. "Corals that have successfully shifted their ranges during warming in the past need special consideration when deciding how to protect reefs now and in the future."
The coral reefs of today are already changing. After suffering through mass bleaching in 2016 and 2017 the Great Barrier Reef of 30, ten, five years ago is no more. In 2016 alone, 30 percent of its shallow water corals died. Those remaining are a different assemblage of species.
Professor Pandolfi says the surviving corals signal a new order.
"It's the same of any community changing over time," Prof Pandolfi said. "If members leave an area, the remaining community becomes very different."
Prof Pandolfi says corals in the past shifted their entire range, from top to bottom, towards the poles. However, the species diversity deteriorated closer to the equator.
"The corals that survived the last interglacial colonised at cooler latitudes," Prof Pandolfi said. "The severe decline in corals closer to the equator suggests it was too warm. They couldn't take the equatorial heat."
His focus now is understanding which coral species dropped out, which taxa are most vulnerable to higher heat—and which traits are specific to those coral species.
"Some traits, such as growth and larval development, are well documented," he said. "But there are a lot of gaps in the current data. We need to incorporate more traits into future studies."
Climate change is forcing many species to shift where they live. In the marine world it's not just corals but fish and plants, too. Collecting enough present-day data on the impacts of climate change to inform conservation is a global problem.
Professor Gretta Pecl from the Institute for Marine and Antarctic Studies and the Centre for Marine Socioecology, both at the University of Tasmania, specialises in climate change ecology. She leads citizen science project Redmap (Range Extension Database and Mapping).
The project enlists the help of thousands of recreational fishers, SCUBA divers, boaters and naturalists. They photograph and report species that are seen outside of their usual geographic range. This helps scientists track and understand the shifts in a timely and cost-effective way.
Prof Pecl's work focuses on global ocean hotspots, such as the east coast of Tasmania—where the seas are warming almost four times faster than the current global rate.
The hotspots provide a glimpse of the impacts for the rest of the world, especially around food security and industry.
"It is important that we understand the changes that are coming, that we prepare for them and adapt the best we can," Prof Pecl said.
Prof Pandolfi and Prof Pecl's work is crucial to understanding what can be done to better protect species on the move across the world's oceans. They will both be presenting at the 2019 Coral Reef Futures Symposium this week at the Australian National Maritime Museum, Sydney.
The symposium also features a free public forum, 'What Every Australian Should Know About Climate Change.' A panel of four world-renowned experts discuss climate change and renewable energy. They will then answer questions from the audience.