http://www.youtube.com/watch?v=x_WR2B_5OQY

“How will you keep from falling through if the ice melts at the South Pole?” She was under the impression that Antarctica was a massive sheet of sea ice, like the Arctic.

Damn – I had no idea about that. I’ve read quite a bit about invasive plants and animals, but never seen anything about earthworms being harmful until I started googling after reading your response.

OK, can’t count earthworms as non-harmful, then, but there are still some introduced organisms that seem to blend into the existing environment pretty well without any serious negative effect on the native species. Overall, though, I agree that there’s probably been enough damage already that people shouldn’t be going out of their way to transplant even more species from one part of the world to another.

(and I learned at age 33 that AC/DC was not from New Jersey but from Australia)

Humans have successfully “transplanted” ourselves many times, and it has often worked out well for the transplanted humans, at least in the long run. For some other living things, it hasn’t worked out so well.

There are actually quite a few inadvertent transplantations of living species that do not appear to have caused very serious disruption to the ecosystem that they were introduced into. Every spring and summer, I see plenty of wildflowers and weeds that originally came from Europe and Asia – dandelions, Queen Anne’s lace, bluegrass, white clover being 4 common examples. Also, I’ve read that most of the earthworm species in the northeastern USA are actually originally from Europe, perhaps brought in ship’s ballast. For that matter, there were no honeybees in North America before Europeans brought them. On the other hand, some introduced species have had a real detrimental impact on native species – the fungi that causes Chestnut blight and Dutch Elm disease, gypsy moth caterpillars, starlings, Bittersweet and Japanese Knotweed (two invasive plants), really can cause a lot of damage. Sometimes, though, the best way to control invasive species appears to be “biological control”, which means controlling invasive introduced species by bringing in predators or parasites or diseases that reduce the populations of the intruders. This can work VERY well because often the reason that the introduced species are so incredibly successful, to the detriment of native species, is that in being transplanted they have left behind the other organisms that preyed on them in one way or another, and none of the native species are adapted to the task. It can also be a huge risk, because the introduced predator/parasite/disease organism might also prove harmful to native organisms – it might hurt them more than it hurts the invader. That’s why today they don’t try introducing “biological control” organisms until they have studied their interaction with the local environment for years. So, not all introduced species necessarily have a negative impact on the native environment – in carefully controlled cases, they can even help.

Sorry to break out into lecture mode – you might already know all of this stuff. It’s just that I find the whole topic of introduced species and invasive species fascinating.