Since being introduced in 1946 in an attempt to jump-start a Chilean fur industry, beavers have been spreading throughout the southernmost tip of South America and tearing apart forests in their path, reshaping one of the world's most pristine regions.
Sounds unthinkable, right? But when the head of Chile's invasive wildlife program leaned over to us and said, "they're trying to colonize the continent," we were hit with a very chilling vision of regimented chisel-toothed rodents marching across Patagonia.
Beavers aren't your average invasive species. They're ecosystem engineers that will raze any cold and wet environment and give it a destructive home makeover until it recreates its own natural habitat. In southern Patagonia, these furball hydrologists gnaw down entire forests to build dams that inevitably cause flooding, which then drown trees and drive out the area's endemic species. (To be fair, humans have been interested in building much larger, more destructive dams in Patagonia, but the region's biggest dam project was killed earlier this year.)
Look at this cute little menace!
Get enough of the little creatures in one place and they're capable of throwing an ecosystem out of whack, and dam-induced flooding can sometimes destroy bridges and roads in its path, too.
According to an internal document published by Chile's Livestock and Livestock Service (SAG), as of 2013, the Chilean government estimated that the beaver's direct impact on forests has cost roughly USD$1,850,000. As the report notes, the spin-off effects of degraded forests (largely in terms of lost ecosystem services) are harder to put a price on, but are "certainly growing in exponential terms."
It all began as a plan to import 25 pairs of beavers from Canada to Tierra del Fuego in southern Chile and Argentina in order to foster a fur trade in an economically stunted region of the continent, but has since spiraled severely out of the control.
With zero natural predators in sight, the beaver's expansion has remained largely unchecked. The Chilean government report pegged the beaver population in Patagonia at around 100,000, and states that the population has affected 23,500 hectares (more than 90 square miles) of forest. Other reports state that the beaver population now covers an area of at least 70,000 square kilometers of Patagonia.
In an attempt to control the beaver population, Argentina and Chile partnered on binational initatives to promote commercial and recreational beaver hunting. When that didn't go far enough, the governments looked to ramp up eradication efforts; bounties were introduced for the capture of beaver for its tails, fur and meat, in order to promote the creation of a market of beaver products, and the governments have taking to funding trapping efforts as well.
During our shoot, we met government-sponsored trappers, rifle-toting animal biologists, and beaver-hungry chefs, all of whom wanted the flappy-tailed woodchippers responsibly annihilated. However, despite the decree to slay any beaver in sight, neither of these programs has managed to keep up with the expansion rate of the beaver's range, resulting in a continued imbalance of the region's ecosystem.
The beaver's wake of destruction is most visible in the graveyard of trees that it leaves behind, especially in an environment where it has few natural predators to keep it in check. As of today, neither the Chilean nor the Argentinian government has managed to identify a sustainable fix to exterminate the beaver. In the meantime, hunters and trappers continue to pursue the beaver in order to protect Patagonia from ongoing invasion.
Symbiotic is a new Motherboard series that delves into the beautiful and twisted interactions between man and animal and the interdependent tussle between the two species in the name of mutual survival.