Heatwaves have massive and widespread repercussions across the land and sea causing death among native plants and animals and impacting food chains, researchers have found.

An international team of researchers, led by Dr Katinka Ruthrof from Murdoch University and Kings Park Science (Western Australia's Department of Biodiversity, Conservation and Attractions - DBCA), documented the responses of plants, animals and marine life to the 2010-11 heatwave in Western Australia.

They found it caused coral bleaching in Ningaloo, sea grass and kelp loss off the WA coast, damaging insect outbreaks and mass tree deaths in the Northern Jarrah Forest. It was also followed by population crashes among endangered Carnaby’s black cockatoos and plummeting breeding success in little penguins in the biodiverse South-West of the state.

In contrast, an increased abundance of tropical fish like the lined dottyback were found in higher numbers following the heatwave.

During March 2011, maximum air temperatures were 2^°C higher than the long-term March average (1971-2011) for the area affected. . The weekly maximum temperature near Perth at the time also exceeded the long-term mean by approximately 5^°C.

These conditions were mirrored in the marine environment, and coincided with a near-record strength Leeuwin Current and one of the strongest La Niña events on record. Sea surface temperatures were 2-2.5^°C higher compared with the long-term March average.

Dr Ruthrof said the broad ranging impacts of the heatwave were ‘staggering’.

“The breadth of animals and plants affected by these heatwave conditions suggest our ecosystems are more vulnerable than we think to the projected increases in heatwave frequency, intensity and duration we are facing in the future,” she said.

“Some of the trees we studied are from long-lived perennial species, which have, no doubt, experienced many extremes in the past, but they died in this event. It was clearly significant.”

The researchers assembled a database of published and unpublished information on the responses of plants and animals to the heatwave in a 300,000 km² area (roughly the size of California) from Cape Leeuwin in the south to Exmouth in the north.

They found the heatwave triggered abrupt, synchronised ecological changes, including deaths, demographic shifts and altered species distributions.

Co-author Dr Joe Fontaine, from Murdoch University, said the findings indicated that extreme events caused by the changing climate, are not a problem for the future, but for today.

“We often speak about climate change in terms of future generations. It is not – this is a current issue that needs to be addressed,” he said.

“In combination with droughts, heat waves are predicted to increase in frequency and magnitude. The land affected by heat waves is expected to double by 2020 and quadruple by 2040.”

Another co-author Dr Jatin Kala, also of Murdoch University, said the study paints the South-West of WA as the ‘canary in the coalmine for climate change’.

“What happens here is a reflection of what is likely to happen for Mediterranean ecosystems across the world,” he said.

A paper on the findings has been published in the journal Scientific Reports.

The research was a collaboration between academics from the University of Arizona, Edith Cowan University, DBCA, CSIRO, and the UWA Oceans Institute.