Invasive species: a battle on many fronts
In 1946, the Argentine government sought to develop a fur trade. So it imported 25 pairs of North American beavers (Castor canadensis) from Canada and released them onto the islands of Tierra del Fuego. The fur business never got off the ground; but in the absence of such predators as coyotes and bears, the transplanted beaver flourished.
Finding itself in a cool land of forests and streams, its population multiplied by the mid-1990s to some 100,000 individuals spread across 7 million hectares in the Argentine and Chilean archipelago. Huge swaths of virgin southern beech (Nothofagus sp) forests fell or were flooded as the beavers built dams. Fast-moving streams were blocked, and aquatic diversity declined.
In August 2008, the presidents of Argentina and Chile signed a bilateral agreement to use hunting, trapping and other methods to wipe out the beaver on the continent’s southern tip. A Chilean government study estimates the endeavor would cost US$30 million, but experts question whether even that will be enough to rid the two countries of one of their most destructive invasive species.