For as long as humans have roamed the earth, they have tried to change it, squeeze something from it or manage it. In the last 50 years or so, the introduction of certain animals, insects or plants into new habitats has been seen as a way to either make money or prevent losing money. In the June 19 issue of Nature, an article entitled “Tierra del Fuego: The Beavers Must Die” highlighted the plight of beavers artificially introduced into the southern region of South America.

Beavers were brought to Argentina from Canada in the 1940s as a way of initiating a fur industry. At the time, beaver pelts were some of the most expensive in the world. However, when fur coats went out of fashion, the market for beaver fur crashed.

Since then, the beavers have increased in number from 50 to 100,000. Unfortunately, since the ecosystem had evolved independent of them, there weren’t any natural predators to restrict the population.

The government now faces a self-induced dilemma: how to stop the devastation wrought on their forests, rivers and ecosystems. This has become a serious problem since 16 million hectares of forest has been affected so far. Whereas North American trees grow back when felled by a beaver, South American trees don’t. This has left huge swaths of deforested land, unable to recover.

The fallen trees create dams which block water flow and turn rushing streams into static lakes. This has created new niches for undesirable species to fill. The foremost concern, however, is that the beavers will mobilize north, destroying forests outside Tierra del Fuego.

An All Out War

To combat this, scientists and government officials are planning to eradicate the beavers using fatal traps, trappers, dogs, boats and helicopters, according to an interview in Nature by Josh Donlan, director of Advanced Conservation Strategies. He states, “We’ve made huge progress over the past five years in removing invasive mammals,” referring to the eradication of goats from the Galapagos Islands.

In this same article, Guillermo Martinez Pastur, a forest engineer at the Austral Center for Scientific Investigation stated that the plan to drive the beavers into extinction “is impossible, or is of extremely high cost.” Regardless, Donlan, who is involved with the eradication project, seems confident it will work.

He might be right since it seemed to work for the Galapagos Islands. In a September 2006 article of Science, it was reported that the Charles Darwin Research Station had partnered with the Galapagos National Park to conduct a six year eradication project.

Funded with $18 million by the Global Environmental Effort (GEF) organization, 140,000 goats were killed in five years using hunting dogs. Rats are next since they are killing the few finches that are left. In 2007, a project to poison feral cats was to commence in order to protect the marine iguanas. The eradication plans continue as a $15 million fund was to be put in place by the national park and research station.

Species have come to reside in new habitats since the beginning of time. However, invasive species can now travel faster than ever before. Many people smuggle plants and animals across borders, introduce them by accident or release their pet into the wild.

In 2005, Pimentel estimated that terrestrial and aquatic invasive species cost the U.S. $120 billion per year in environmental damages and losses. According to the National Oceanic and Atmospheric Association (NOAA), 50,000 non-native species are found in the U.S. This has caused native species to be suppressed so dramatically that they constitute 42% of the species found on the threatened and endangered species lists.

Pimentel also estimated in 2000 that invasive species cost the U.S. $137 billion due to damage to the ecosystems and agriculture. The U.S. isn’t the only country affected. In New Zealand, the varroa mite was introduced and has become a problem for honeybee hives costing $267-$602 million in damages. Eradication is now impossible. Instead, $1.3 million has been earmarked for the first stage of a project to manage the problem. In 1992, the Weed Society of America reported that invasive weeds cost $4.5-6.3 billion while in South Africa, invasive tree species cost the Cape Floral Kingdom $40 million each year to control.

The Benefits

Not all the consequences of animal introductions are bad. The tourism in Tierra del Fuego, for instance, has been bolstered by the beavers. Tourists come to see the furry creatures and the National Park has established trails specifically for those who wish to see them. The beavers also benefit the travel agencies who structure trips to include visits to see the furry aquatic rodents.

The population, however, is simply too great for the environment to support without any natural predators. In 1998 the New York Times reported that Argentina had tried to convince Europe to open their doors to beaver fur, allowing them a financially beneficial solution. Europe refused, stating the inhumane traps were unacceptable.

Argentina acquiesced and spent $50,000 to buy humane traps and train hunters in Tierra del Fuego to use them. These traps killed the beavers immediately rather than breaking their back legs, causing them to suffer. Europe still refused citing inhumane traps were used elsewhere. Argentina rejected outlawing the traps completely since they were being used for fox and coypu which generated an income of $80 million each year in exports.

Although, there are uses for animal introductions, much more thought needs to be applied before starting a project that will be virtually impossible to reverse. This is especially important since introduced animals and plants tend to travel. Not only is the area itself under threat when populated by introduced species, but so are any neighboring ecosystems. Luckily, scientists are looking at the prospect of introductions much more carefully, conscious of the impact if the project goes awry.