The human-led introduction of invasive North American beavers to Patagonia produced a large-scale negative effect on the native environment.

In 1946, the Argentinian military saw their northern neighbors reap the profits from the fur trade and decided to relocate 10 pairs of beavers to Tierra del Fuego, in an effort to attract more residents and stimulate a fur-trade of their own. It was a disaster and the beaver population, left uncontested, grew exponentially and rapidly spread throughout Patagonia. A recent article on National Geographic by Haley Gilliland states, “Left largely unchecked since then, the Global Environment Fund estimates the beaver population has grown to 110,000 in Patagonia and Tierra del Fuego.”

Beavers are known as ecosystem engineers because of their ability to construct, maintain, and destroy habitats for their needs. In North America, this species is not an issue as the trees adapted co-evolutionarily to the beaver’s presence and developed defense mechanisms to their form of predation. In the drastically different environment of Argentina, invasive beavers are destructive drivers of ecological change. Since beavers are not native to South America, the continent’s trees have not developed the same adaptations.

Trees like willow, cottonwood, American beech, and alder have all evolved responses to beaver chewing and flooding. They re-sprout when you cut them down, produce defensive chemicals, and tolerate wet soils,” says Environmental journalist, Ben Goldfarb.

As a result of this, “beavers have colonized at least 27,027 square miles of territory and decimated nearly 120 square miles of peat bogs, forests and grasslands” and their impact on Patagonia has been stated to be “the largest landscape-level alteration in sub-antarctic forests since the last ice age.” In their wake, they leave phantom forests. Dead trees so pale in color that you mistake them for ghosts.

The main concern is their invasion of the Tierra del Fuego archipelago. Although difficult to reach, if the beaver’s were to populate the fragile island system, it would quickly be decimated and it’s native plants and animals will be at risk of extinction. 

Our world today is in the midst of a major wave of species extinctions, of which are primarily caused by invasive species, especially on islands. Islands are very fragile ecosystems consisting of native species with incredibly specific adaptations. The biodiversity on islands is so highly concentrated that its disproportionate to its landmass. Because of this, the introduction of an invasive species to an island system, like the beaver, will eventually decimate all original forms of life. When we lose species, ecosystems unravel, and we see and feel the direct effects on the natural world, our livelihoods, and our overall well-being.

This example is only one of thousands that are threatening the stability of delicate island ecosystems. That is why we, as a global community, must take action and remove the invasive species and return our planet to its natural stable state.

Featured photo: Andrea Monari
Source: National Geographic