Invasive Species

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  • Topic: Invasive species, Introduced species, Genetic pollution
  • Pages : 6 (2108 words )
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  • Published : February 17, 2013
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Shao Yang
ENGL 1020_001
4/10/11
James Ross
Aftermath of the Invasion
The introduction of invasive species into new environments is a problem that plagues the entire planet. Humans have been moving species around the world and introducing them into new environment for millennia. Many introduced species become invasive, disrupting ecosystems and threatening the survival of other species, sometimes driving them to extinction. Some invasive species, including some insects, seem to thrive particularly well in already degraded environments. After habitat destruction, the issue of invasive alien species is thought to be the greatest current threat to biodiversity. A suggestion for a solution is to ban import of all exotic and harmful species or perform biological control which entails introducing a natural enemy usually from the native range of the introduced pest.

Although invasive species are a serious environmental, economic and social problem worldwide, could it be more of a natural process than human intention? For example, wind is able to carry seeds, pollens, and plants from continent to continent and make them become invasive. Furthermore, “The Bering land bridge, which joined present-day Alaska and eastern Siberia at various times during the Pleistocene ice ages, is believed to have enabled human and animal migration to the Americas from Asia about 20,000 years ago” (Lockwood, 108). In addition, most of our food crops are intentionally introduced but turned out to be very beneficial. However, it is important to remember that even though not all introduced species are invasive and harmful, but most of them are highly demanding and ecologically unfriendly.

Humans carry with them their plants, seeds, and domesticated animals, as well as pests and microbes that cause epidemic disease around the planet. “Most of these transported organisms, which either arrive accidentally as “hitchhikers”-for example, on clothing, in used tires, in wooden pallets, or in the ballast water of ships-or are deliberately introduced. But most introductions are not deliberate” (Chivian, 47). Invasive species may negatively impact native species in any number of ways. The impacts include eating them, competing with them, interbreeding with them, or introducing pathogens and parasites that sicken or kill them. After all, invasive species affect nearly all habitats on Earth, ranging from wilderness areas, to croplands, rangelands, and forests, as well as freshwater and marine ecosystems. Invasive species disrupt the ecosystem by dominating a region or wilderness areas, particular habitats, For example, the brown tree snake is infamous for being an invasive species responsible for devastating the majority of the native bird population in Guam. “The Pacific island of Guam has lost almost all of its native forest birds as well as most of its lizards to a tree snake, Boiga Irregularis, thought to have arrived there as a cargo stowaway on U.S. transport ships during World War II (The snake is aggressive and poisonous enough to hospitalize about fifty people a year on Guam)” (Terrill, 101). The health of the ecosystem has also suffered from invasive species because invasive species not only drive some native animals or plants to extinction, but also decrease the overall biodiversity through hybridization. The impact of crossbreeding is tremendous because it reduces the gene pools of various wild and indigenous breeds resulting in the loss of genetic diversity. In fact, introduced species are a greater threat to native biodiversity than pollution, harvest, and disease combined. There are many ways developed to deal with the problem such as invasive species. Biological control is the deliberate use of one organism to manage the population size of a pest organism, however, it might disrupt the ecosystem and the result is often unpredictable. Some biological control agents not only failed to control the pests but also become invasive. For example,...
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