24 February 2021: University of Canberra Research Fellow Dr Joanne Bennett has discovered that many species will be left vulnerable in the face of climate change, unable to adapt their physiologies fast enough to respond to rapid global warming.
A Research Fellow at the University’s Centre for Applied Water Science (CAWS) at the Institute for Applied Ecology (IAE), Dr Bennett wanted to understand how species’ thermal limits have evolved, in order to predict how they might respond to these temperature hikes.
In work published recently in the Nature Communications journal, Dr Bennett and her co-authors draw on the largest available database compiling thermal tolerances for all types of organisms (GlobTherm database) to explain the variation in tolerance to heat and cold across the tree of life.
Dr Bennett and her colleagues found that a species’ thermal tolerance is linked to the current climate where they live.
"It is logical that species that live in very hot regions tend to tolerate heat better, but the question is: with the increase in temperatures imposed by climate change, will species be able to continue adapting to the heat indefinitely?" Dr Bennett said.
The researchers also found that tolerance to cold has evolved much faster than tolerance to heat, particularly in endotherms as compared to ectotherms and plants.
Endothermic animals are those that generate metabolic heat to regulate their own body temperature – for example, mammals and birds – while ectothermic animals are those that regulate their body temperature using external heat sources, like reptiles, fishes and invertebrates.
The cause of this disparity is most likely an evolutionary barrier, a maximum thermal tolerance beyond which further evolution is constrained or selected against.
“This is very concerning because it suggests that the vast majority of species will not be able to adapt fast enough to survive the unprecedented rate of contemporary climate change,” Dr Bennett said.
The results of this study are particularly relevant to conservation management, Dr Bennett says.
“Identifying, prioritising, creating, and managing areas that provide refuges for biodiversity from warming and extreme events under climate change may be one of the only available strategies for conservation managers,” she said. “This is the focus of my current work with Professor Ross Thompson at the Centre for Applied Water Science at the University of Canberra.”
Dr Bennett also wrote about the study in a Nature Ecology and Evolution blog post.