Curtin University researchers have found that some plants in Western Australia\u2019s South-West region established under drought conditions are likely to have reduced growth, but be more resistant to drought in the future.<\/p>\n
Lead researcher and Curtin PhD student Ms Haylee D\u2019Agui, from Curtin\u2019s Department of Environment and Agriculture, said researchers examined the growth of seedlings of four fire-killed species from the family Proteaceae \u2212 Banksia hookeriana, Banksia leptophylla<\/em>, Hakea costata<\/em> and Hakea polyanthema<\/em> \u2212 from the biodiverse Kwongan region in WA\u2019s South-West.<\/p>\n \u201cWe 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,\u201d Ms D\u2019Agui said.<\/p>\n \u201cThe seedlings rapidly adapted to climate change through changes to their genetic and physical makeup, including growing denser leaves \u2212 which enabled them to absorb and store water more efficiently and therefore have more chance of surviving drought conditions.<\/p>\n \u201cThese findings are significant as modelling suggests that 10-25 per cent of plants in the region would go extinct under currently projected climate change.\u201d<\/p>\n Ms D\u2019Agui 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.<\/p>\n \u201cOnly 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,\u201d Ms D\u2019Agui said<\/p>\n \u201cRapid 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.<\/p>\n \u201cFuture 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.\u201d<\/p>\n