[Post Toasties]

Actually, what you are afraid of has already happened numerous times, and it doesn't take a species preserved in ice from 30,000 years ago to cause it.

There must be dozens, if not hundreds of instances where species from one continent, say, Asia has been introduced to North America and significantly changed parts of the biosphere, species like the Asian carp which have largely taken over the Great Lakes. Or the zebra mussel from Russia which was introduced into the Great Lakes by ships emptying their bilges.

And how about Dutch Elm Disease and Chestnut blight, both imported tree diseases that have transformed many thousands of square miles of forest?

Then there are invasive species. On my property, buckthorn and honeysuckle plants gone wild are replacing much of the natural undergrowth and inhibiting new tree growth in forested areas as they are over much of the United States.

Virtually all of these invasive species grew elsewhere on earth for tens of thousands to millions of years before being inadvertently introduced to the American biosphere where in many cases they have few or no natural enemies to keep them in check.

[KC_Lion]

"buckthorn and honeysuckle plants gone wild are replacing much of the natural undergrowth and inhibiting new tree growth in forested areas as they are over much of the United States."

I heard that!

I guess even the more reason to be careful introducing Extinct plant (or animal) spices back in the Biosphere.

[exDemMom]

Virtually all of these invasive species grew elsewhere on earth for tens of thousands to millions of years before being inadvertently introduced to the American biosphere where in many cases they have few or no natural enemies to keep them in check.

The state of California is so overgrown with non-native flora that it is difficult to imagine the state's original appearance.