Occasionally, a foreign, introduced species can cause extensive damage to the environment to which it is introduced by spreading diseases, damaging the ecosystem, or causing economic harm. We call these species invasive.
Between 1911 and 1914, a team of four people successfully eradicated the tse-tse fly, which carried the sleeping sickness, from the island of Principe in the Gulf of Guinea, where the fly had been since it was first introduced in 1825 (Lapeyssonie, 1988). Since that first successful eradication, there have been a series of attempts to remove invasive species from progressively larger islands and even substantial parts of continents; many of which have been met with success (Simberloff, 2002). A major example of a large eradication attempt was the worldwide eradication of smallpox celebrated by the World Health Organization in 1980 (WHO).
Eradicating invasive species is only effective if they are not immediately re-introduced: in the case of the tse-tse fly, a second eradication was needed when the fly reappeared in 1956. Although the effort involved a larger group of people, it took only two months and cost about 7500 pounds. The cost of eradication is often proportional to the area the species has spread over, a process which takes time, and therefore eradication efforts are cheapest and most likely to be successful when started early (Simberloff, 2002).
Biosecurity Australia helps prevent invasion or re-invasion by writing risk analyses on new and existing imports to develop policies and advise Australian Quarantine and Inspection Services. Australia is still remarkably pest and disease free for a delicate island ecosystem (Australian Quarantine and Inspection Service). Upon first entering Australia, the AQIS ensure that no species with the chance of becoming invasive enters the country, and they do so by having checkpoints in the airports with scanners that detect bacteria. By working closely with biological experts and with each industry affected by quarantine, the AQIS has created ICON, a database of over 20,000 import conditions on different products. Additionally, the AQIS has made an attempt to branch out to the general public through television. AQIS has celebrities with a connection to biodiversity, such as the late Steve Irwin, endorse their organization. The budget dedicated to Australian Biosecurity is about 500 million AUD over four years (Australian Budget, 2005).
We recommend that other island nations or areas threatened by invasive species adopt a joint system of quarantine and inspection to prevent invasion. Additionally, nations must develop a plan for immediate response to erradicate recent invasions. Quarantine and inspection services ban the purposeful introduction of new species to an environment for gardening, along with separating and holding imports that might contain invasive species, for instance wooden packaging materials, for a set period of time in order to guarantee there are no hidden species. As policies vary by ecosystem, product, and circumstance, we recommend that each country have a research agency or coalition analogous to Biosecurity Australia to make recommendations. Immediate response teams are often slowed by political pressures unless a system is in place before an invasion, so developing these mechanisms preemptively is very helpful.
Eradication of widespread invasive species, however, faces many more obstacles. Efforts may fail to eradicate the species, require excessive funding, and can often severely damage the habitat they are trying to protect from the invasive species (Simberloff, 2002). In the long run, however, the money put into erradicating an invasive species is often worthwhile; the total cost of invasive species has been estimated to be 5 percent of the world's annual GDP (The Nature Conservancy, 2011).
Once a species has been eradicated, particularly over a short period of time, efforts must be taken to stabilize the ecosystem. These efforts would entail re-introducing native species that were either out-competed or hunted by the invasive species (Simberloff, 2002). It is also important to note that not all invasive species are equal in terms of their destruction to an ecosystem, meaning that a nation must evaluate the cost of eradicating the species relative to the cost the invasive species incurs against ecosystem services (Simberloff, 2002). In general, however, a precautionary measure must be taken in determining the cost of an invasive species, as we do not have proper measurement methods to calculate all the indirect consequences of an invasive species.
Another promising but less tested technique that relies on economic methods instead of government control involves large-scale commercial hunting, which is based off the idea that introducing a predator of the invasive species will solve the problem. This is because non-native species lack predators in their non-native ecosystems, so the addition of a predator will force the non-native species population to stay in check (Ecological Society of America). While government programs are inherently limited in scale by cost, any technique which results in economic benefit will inherently have no economic limit because once the groundwork is laid down, there is no net cost to continue operating. A program like this has been implemented to a small extent in the Cayman Islands in the Caribbean, where the red lionfish, an exotic fish native to the Indian Ocean that had been introduced to the region as pets, has entered the ecosystem and displaced the native wildlife and even threaten larger predators with their venomous spines (Barbour, 2011).
In the past, humans have nearly or completely wiped out entire species through over-hunting, so in theory it should be possible to do the same with invasive species. To this end, many local divers have begun to spear the red lionfish and organizing "hunting derbies" among recreational divers. To provide financial backing and motivation, restaurants are beginning to serve red lionfish as a delicacy (Barbour). If the trend catches on, "human gourmets may do for red lionfish what they've already done for numerous other edible marine creatures, generating sufficient demand to drive the species' numbers way, way down" (Barbour). However, spearfishing is a tedious and relatively expensive process compared to more industrial fishing methods such as trawling, which would be impossible without damaging the precious coral reefs or indigenous fish. To expedite the eradication process, humans will need help from local predatory fish such as groupers and sharks (Barbour). To train the local indigenous predators to hunt the red lionfish, conservationists spear the fish, remove the venomous spines, and feed them to groupers, which have already begun to recognize the red lionfish as a food source (Barbour). Other similar creatures to these red lionfish are the Burmese Python and the Nile Monitor because these are invasive species that lack predators in their non-native environments, and thus grow with no constraints (National Environment Coalition on Invasive Species). Hopefully, they will soon begin to hunt the invaders on their own.
Evidence of this plan's benefits are already apparent. In West Virginia, local hunters have turned their attentions towards the invasive European boar. In certain regions, the harmful boars have been nearly eradicated (Witmer, 2003) Were unrestricted hunting of invasive species permitted in areas where they cause the most damage, hunters should have no trouble controlling them far more effectively than governmental culling initiatives. Federal subsidies would then incentivize the sale of invasive meats in the U.S., with little cost to our program. The total expense of the program includes the value of the subsidies and the cost to get the FDA to approve each food source for human consumption.