A long time ago, everyone thought that nature was just a big, easily tinkered machine, there was a fad for transporting awesomely successful life forms across the globe (which they would not usually do themselves*).
From Daniel Martins at the Weather Network:
If you’re wondering what in blazes Canadian beavers are doing so far away from the Frozen North, that is a excellent question whose implications the Argentine government should probably have thought a little harder about.
Instead, it seems to have been with a mixture of pride and hopefulness that, in 1946, the government flew 20 beavers from Manitoba first to Rio de Janeiro, then to Buenos Aires, and then on by seaplane to Lake Fagnano, in the interior of the remote Tierra del Fuego archipelago at the southern tip of South America. The plan was to introduce the beavers to a habitat that must have seemed similar to Canada, in the hopes of jump-starting a native fur-trading industry. More.
Hey, beavers have many virtues. They are good parents and work very, very hard at what they do for a living: Killing trees and using the wood to dam watercourses. In Canada, where trees and water are defining qualities in most regions, that’s not a problem except when the beavers are flooding rural roads or causing power outages.
Beavers were shipped to South America without their predators (fishers, coyotes, hawks, brown and black bears, northern river otters, lynx, eagles, mountain lions, owls, wolverines and wolves). So now about 100,000 of the large, tireless rodents are wreaking havoc on the riparian forest in Tierra del Fuego. Culling is getting underway.
By now, it is generally understood that if we can’t ship Ontario to Argentina, it’s not a good idea to just try shipping a small piece of it there.
* Though we can’t always tell. See also: Biogeography: Monkeys sailed the ocean blue?
Nick Matzke’s research critiqued in Journal of BioGeography