New research in Australia gives real hope that plants can respond to climate change, by rapidly evolving. This is the first study, published in the Journal of Ecology that shows just how widespread this ability is in plants.
In less than a hundred years, 70% of 23 non-native plant species accidentally introduced to Australia were able to make major changes in height or leaf size or shape to cope with the new drier and harsher environment that they found themselves in. The arrivals, which are mostly from a much cooler and wetter Europe had to change or fail to thrive.
'People used to think that evolution only happens over millennia, what our work is suggesting is that evolutionary changes to plants can occur within decades, even a single human generation, and that this probably happens often,' said Joanna Buswell, lead scientist and ecologist from the University of New South Wales. 'Our results give us real hope that at least some plants will be able to adapt to changes in climate over time.'
The type of changes depended on what climate the plants were introduced to. Some species were able to halve their height, reduce their leaf size, or develop narrower leaves, all adaptations to a hot and arid Australian climate. These adaptations are common in Australian natives that are already adapted to survive in these conditions. One species which found itself in the cooler and wetter coastal belt more than doubled in size.
'This plant had taken advantage of the fact that it had more water and cooler temperatures by getting taller,' says Buswell. All of the plants in the study were annuals or short lived perennials that would have gone through many generations in the hundred years since their arrival in Australia. 'The rate of change and adaptability is likely to be much less for longer lived species like trees and shrubs,' says Dr Angela Moles, the senior scientist on the project, 'but the results tell us that at least some plants can adapt quickly to changing environmental conditions.'
The study also looked at herbarium specimens of the same plants over the same period collected in their native Britain and they showed none of the dramatic changes seen in Australia. 'It really looks like the changes are occurring in response to a change in environment, our work is proof that evolution is happening all around us,' said Moles.
The study plants are mainly classified as weeds in Australia, but at some point with this rapid rate of change they will become new species. The researchers have begun further work to confirm the genetic basis of the changes.