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ambience: dawn chorus, Ventana Wilderness
Alien invasions happen every day on Earth — but not from outer space. I’m Jim Metzner, and this is the Pulse of the Planet. Every form of life on this planet has the potential to be an alien invader – all that a species has to do is be transported out of its home land and into a foreign ecosystem. Mark Lonsdale is an Australian ecologist who studies invasive species.
“What happens when we introduce an organism to a new range is that we often leave behind the natural enemies that keep it under control in the place where it comes from. So its diseases, its competitors, are often left behind, and you end up with a population which is able to flourish without challenge in this new range.”
It’s usually people who intentionally or accidentally introduce an invasive species. And since foreign species can do great damage to agriculture and to the health of a local ecosystem, the challenge is for science to find ways to control the invader without making things worse.
“In terms of managing those species, we can return to the country of origin and seek the natural enemies, the biocontrol agents, and introduce those into the new range. We have a lot of weed problems in Australia. We go to the native range of those weeds, and we look for insects and fungal pathogens, fungal diseases, and introduce those to control the weeds. We have to do a lot of testing to make sure that those species that we introduce don’t cause yet further problems.”
And so scientists are trying to find ecologically safe ways of eliminating invasive species. Determining whether or not a biological control agent – such as an insect or a fungus – would be a harmless addition to an ecosystem, typically takes years of careful research.
Pulse of the Planet is presented by the National Science Foundation. I’m Jim Metzner.
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