In 1946 the Argentine Navy imported 10 beaver couples from Canada and set them free in Isla Grande, the deep south of Tierra del Fuego, with the intention of "enriching" the native faunaand the local fur industry. The consequences of such initiative were disastrous: Protected from hunting for 35 years, and devoid of natural predators, the beavers grew over 5,000 times their initial population, caused irreversible changes in the forest ecosystem, and started advancing over the continent. Now, a study published in Chilean Natural History suggests that the demographic explosion of those beavers could be bigger than suspected because it can take years or even decades for local inhabitants to notice the rodents' presence and their impact on the surrounding ecosystems.
When the expansion of the Panama Canal is completed in 2016, giant ships that now must dock at West Coast ports after crossing the Pacific will be able to deliver cargo directly to ports on the Gulf of Mexico and the East Coast. One thing they may be delivering, according to a recent study, is a much larger number of alien species.
Thomas Reuters Foundation News.