Enemy invaders or rare new species?

Nicky Phillips Sydney Morning Herald 30 Jan 11;

INTRODUCED plant species are becoming stronger, more versatile invaders by rapidly evolving to suit Australia's harsh climate, research has found.

Sydney scientists studied more than 20 introduced species and found that 70 per cent had changed significantly in less than 100 years.

The silver lining to this find, said study co-author Angela Moles, is "if the introduced plants can change rapidly, it gives us hope that a decent proportion of our native flora might be able to change in response to climate change".

Researchers studied introduced herbs and grasses because they were fast-growing and would have gone through multiple generations since their arrival.

Some species had halved in height and leaf size, becoming more like Australian natives.

"That makes a lot of sense. If you are growing in a low-nutrient, low-rainfall environment like Australia, you don't want to be a big lush plant," Dr Moles said.

The researchers also analysed the rate of change of Australian native grasses, as well as of the introduced species in their native environment in Britain. Neither group transformed as much as the introduced species in Australia.

"It really looks like the changes are because they've been introduced into a new environment," Dr Moles said, adding that this study was proof that evolution was "happening all around us".

The findings also raised an interesting question about how introduced species are classified.

"If they keep changing … they are eventually going to become different species," Dr Moles said.

"At that point do we keep trying to eradicate these things or do we treasure them because they are a rare new species?"