Invasive species pose huge threat to ecosystems, UN says

It's no longer than a grain of rice. But the mountain pine beetle is an insidious environmental predator, laying waste to swathes of forest in north-western Canada and exposing the local ecosystem to what could be a devastating new front in the battle against climate change.

The beetle is one of hundreds of what scientists call invasive species – animals, plants and organisms that “arrive, survive and thrive” in previously inhospitable territory and damage their host environment.

Now, as global warming alters temperature and precipitation patterns around the world, the threat posed by invasive species is rising, and scientists and United Nations officials are calling on participants at next month's climate change conference in Copenhagen to agree to action to strengthen their ecosystems and to protect biodiversity.