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WA plants rapidly adapt to declining rainfall

Media release

Curtin University researchers have found that some plants in Western Australia’s South-West region established under drought conditions are likely to have reduced growth, but be more resistant to drought in the future.

Lead researcher and Curtin PhD student Ms Haylee D’Agui, from Curtin’s Department of Environment and Agriculture, said researchers examined the growth of seedlings of four fire-killed species from the family Proteaceae − Banksia hookeriana, Banksia leptophylla, Hakea costata and Hakea polyanthema − from the biodiverse Kwongan region in WA’s South-West.

“We simulated environments affected by drought and found those Proteaceae species established in dry years maintained higher survival rates than offspring of plants established in average annual rainfall years under simulated drought,” Ms D’Agui said.

“The seedlings rapidly adapted to climate change through changes to their genetic and physical makeup, including growing denser leaves − which enabled them to absorb and store water more efficiently and therefore have more chance of surviving drought conditions.

“These findings are significant as modelling suggests that 10-25 per cent of plants in the region would go extinct under currently projected climate change.”

Ms D’Agui said the rainfall of the relevant year and other stress response pathways present when the plants first started to establish themselves served as a filter for natural selection.

“Only those plants with drought-resistant genes were selected to grow in dry years. This means the entire population growing at that particular time will be more likely to survive future droughts as will their future generations,” Ms D’Agui said

“Rapid adaptation to climate change may, however, vary among species, depending on their capacity to maintain robust populations under multiple stresses, including drying climate and altered fire regime.

“Future studies are needed to empirically test the effect of loss of genetic diversity through rapid evolution in response to a drying climate, or other stressors, on overall population variability.”

Published in the journal Royal Society Open Science, the full paper entitled Phenotypic variation and differentiated gene expression of Australian plants in response to declining rainfall, can be found on the Royal Society Open Science website.

The research was funded by the Australian Research Council.