Exotic Invasion John Tibbets Abstract
Exotic species are booming in population around the world, killing native plants and animals and endangering human health by introducing parasites and pathogens. Once exotics take hold in an environment, they can be extremely difficult to eliminate. Biological invaders are especially a problem in regions where extensive international trade occurs. For example, about 46% of New Zealand's species are nonnative, compared to about 1% of Tanzania's species.
Human pathogens hitchhike across borders and oceans, stowing away on research animals, tropical fruits and vegetables, creatures imported as pets, and mosquitoes. Ballast water is another frequent conveyance for exotic pests. When a ship enters port, its ballast water is dumped, spilling out exotic species that may include human pathogens and toxic algae.
Biological invasions are exacerbated when exotics spread from freshwater ports into rivers and inland lakes. In the United States, the zebra mussel, introduced to the Great Lakes in 1986, has already spread as far away as Louisiana and Tennessee. There is a chance it could eventually reach California.
Most governments have been disorganized and unfocused in their response to exotics, with the notable exceptions of Australia and New Zealand, which use aggressive and often controversial methods of ridding themselves of imported pests. But, while Australia may use questionable methods to get rid of exotics, at least it has a focused national agenda to cope with invaders. In contrast, the United States has no national policy to deal with biological invasions.
At the Earth Summit in Rio de Janeiro in 1992, 165 nations signed the United Nations Convention on Biodiversity. The treaty's sole initiative toward controlling exotics does not have the authority of international law. However, the Jakarta Mandate, formulated by the parties in 1995, offers guidance on controlling exotic species in the marine environment, though it, too, is not legally binding. In July 1996, parties to the biodiversity convention met in Trondheim, Norway, to discuss the issue of exotic species, but no further guidelines were issued at that time.
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