Some invasive species are so entrenched and have evolved so much they might need to be rebadged as "new natives", a researcher says.
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James Cook University ecologist Daniel Montesinos says the unprecedented integration of invasive species into native habitats raises a sticky issue for botanists.
And that's when to accept an invader as an ingrained part of the landscape, with enough evolutionary changes to set it apart from populations elsewhere.
Dr Montesinos says accepting that some invasive species are here to stay isn't about diminishing the harm they do and it's crucial to fight new incursions.
It's more about acknowledging the inevitable and how exotic species have physically adapted to suit Australia's unique conditions.
"I do think there may be new species that could be named, but it hasn't officially happened," says the ecologist, based at the Australian Tropical Herbarium.
"I think this is because botanists are very reluctant because they know it will be something very tricky to say that these invasive species now will be a new native species. The point is to open this Pandora's box, to get everyone to think on this."
The process Dr Montesinos is referring to is speciation - the formation of new and distinct species in the course of evolution.
"Adaptations commonly involve differences in physiology, size, growth rates and fitness, which result in significant differences in invasive populations from their origin," he says.
"The evidence we have from some invasive alien species indicates their transformation into a new species is closer than we expected, it's now a matter of when not if."
Evidence of native ecosystems adapting to the presence of invaders is also mounting.
One example is that native plants can, over time, become increasingly tolerant to chemicals invaders produce to inhibit the growth of other species.
Pollinators, including native bees, also change their behaviour as the landscape changes.
"We see this kind of thing all the time in our gardens. Many of the flowering plants we have are not native. But insects will pollinate anything that gives them food," Dr Montesinos says.
"We are seeing invasives being integrated into the network of flowers, and becoming part of communities. At some point we'll have that knowledge, that they are almost native, or native."
Australian Associated Press
