For more than 7.5 million years, the North American Beaver was able to carve out an ecological niche in parts of the continent, helping birds, plants, and other mammals thrive, according to the Washington Post.
But in 1946, 25 of these beavers, also known as Castor canadensis, were brought to Argentina from Canada to promote the fur trade.
Unlike in North America, the beaver didn’t mesh in its new environment. Because it had no predators, the beavers reproduced rapidly, growing to more than 200,000 today, and spilling across the border into Chile. Throughout this time, the beavers destroyed rivers and chewed forests down to stumps, the Washington Post reports.
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And this invasive species isn’t just affecting the immediate environment — it's also altering the gases in the air and, ultimately, contributing to global warming. The ponds that beavers create out of rivers can be huge producers of greenhouse gases like methane and nitrous oxide, according to Science.
It has, overall, been a case of an invasive species run awry, the Los Angeles Times reports.
The Chilean government has gone to extreme lengths to try and control the population, spending $7.8 million to fund a project to put traps out and kill them.
"It would be too optimistic to think of extinguishing this invasive species in the short term, but we can expect a better control of it,” Pablo Badenier, the Chilean Environment Minister, told the Los Angeles Times.
And now the governments of Argentina and Chile want to kill 100,000 of the rodents.
Argentina’s plan for getting rid of these beavers is similarly simple — train a group of hunters to trap and kill the beavers, according to Business Insider. The country is expecting to have positive results within 15 years. But for the forest to recover, it could take another 80 years, because the beavers have changed around 15% of the land area and 50% of the streams of the Tierra del Fuego, an archipelago off the southern coast of South America, according to the Post.
Invasive species can pose big threats to environments around the world. Among other things, they can kill off or crowd out existing species, spread disease, and destroy wildlife, according to the National Wildlife Federation.
For example, an East Asian tick has found its way to the US and could pose serious health threats in the future. Additionally, gypsy moths from Europe are very harmful to trees in North America.
Read more: A Potentially Deadly Tick From East Asia Found Its Way to the US
Invasive species are becoming more common as human commerce accelerates, according to the International Union for Conservation of Nature (IUCN). In fact, over the past 200 years, one-third of all invasive species were introduced after 1970, IUCN notes, and these animals and plants are disrupting ecosystems the world over.
"Invasive alien species are among the main issues against biodiversity in the planet, and the world is just waking up to it,” Barbara Saavedra, head of Chile Wildlife Conservation Society, told the Los Angeles Times.