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| Characteristics of a brown tree snake, one of the invasive species in Guam. |
How would you feel if you were baited with drugged food? To the brown tree snake, known scientifically as Boiga irregularis, this would mean certain death. Native to the northern and eastern coasts of Australia, Papua New Guinea, and miscellaneous Pacific islands, this species has made its way onto foreign regions, the most serious of outbreaks in Guam. With the overabundance of prey and a lack of natural predators in Guam, Brown tree snakes reached unprecedented numbers, and grew from the norm of six feet in its native land to over ten feet in Guam, causing countless problems for the country.1
The brown tree snake is one of the primary threats to Guam's biodiversity. Massive ecological damage has been done to the island's bird populations, bringing 10 of the 12 native species to extinction and severely reducing the numbers of the other two.2 Significant changes enveloped the forests as the few surviving birds flocked to more urbanized areas. With the declination of birds, there were less predators for insects, so they rapidly grew in numbers and overfed on agricultural and native plant species. Another consequence with the disappearance of the birds was that plants that relied on seed dispersal and pollination were overtaken by other species, narrowing the composition of the forest. A natural disaster would easily overwhelm the vegetation due to the lack of biodiversity in the region.
A general trend in the data is that the size of the brown tree snake population is directly proportional to the number of electrical outages in Guam. If left unattended, the frequency and intensity of damage done by brown tree snakes would increase.
Until now, brown tree snakes have posed a serious threat to Guam's ecosystem, damaging both animals and plants alike.3 Subsidized by the U.S. Departments of Defense and Interior, researchers at the U.S. Department of Agriculture (USDA) Wildlife Services have developed a method to combat the overwhelming invasive population. By injecting dead mice with 80 milligrams of concentrated acetaminophen, a drug found in Tylenol that helps relieve fevers and pains, it effectively alters them into biological landmines for brown tree snakes. It usually takes about 60 hours for the drug to kill an adult brown tree snake, during which it plays out its role, which is to upset the ability for the snakes' blood to carry oxygen.4 The laced mice are loaded on a plane and released over the infested area. From the time of deployment to the time of ingestion, the mice are hooked up to a mechanism designed to tangle within the upper branches of the trees, out of harm's way for nontarget species, but within reaches for the snakes.
Even with all these seemingly cunning ways of eliminating brown tree snakes, at best the efforts will only control the population. Haldre Rogers, a biologist at the University of Washington, says, "It's another arrow in our quiver... Unfortunately, we don't have the silver bullet for Brown tree snakes yet." In the future, researchers at USDA hope to develop a non-biological alternative, as the current model attracts decomposers and unwanted pests. However, as researching and testing biocontrols is budget-heavy, it may be awhile before Guam's biodiversity fully recovers from the terrible terrible damage that brown tree snakes brought upon the island.
Sources:
● "Snake Plague on Guam Impacts Trees." National Geographic. N.p., n.d. Web. 25
Sept. 2010. <http://blogs.nationalgeographic.com/blogs/news/chiefeditor/
2008/08/snake-plague-on-guam-impacts-t.html>.
●"Spotlight On An Invasive Species: The Brown Tree Snake and Its Devastation of
Guam." Bright Hub. N.p., n.d. Web. 26 Sept. 2010.
<http://www.brighthub.com/environment/science-environmental/articles/
41526.aspx?p=2>.
● "The Brown Tree Snake." United States Department of Agriculture - Animal and
Plant Health Inspection Service. N.p., n.d. Web. 25 Sept. 2010.
<http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_wsbtsnake.html>.
● Than, Ker. "Drug-filled Mice Airdropped Over Guam to Kill Snakes." National
Geographic. N.p., n.d. Web. 25 Sept. 2010.
<http://news.nationalgeographic.com/news/2010/09/
100924-science-animals-guam-brown-tree-snakes-mouse-tylenol/>.
● "The Brown Treesnake." US Geological Survey. N.p., n.d. Web. 26 Sept. 2010.
<http://www.mesc.usgs.gov/resources/education/bts/bioeco/btsnake.asp>
● "Electrical Problems Caused by the Brown Treesnake." US Geological Survey. N.p.,
n.d. Web. 26 Sept. 2010. <http://www.fort.usgs.gov/resources/education/
bts/impacts/electrical.asp>.
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