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When the American Association for the Advancement of Science met in Anaheim, California in 1999 to discuss an urgent report on the impact of alien species, the scientists gathered weren’t discussing species from another planet–their report referred to species imported to the United States from other parts of this planet.

Cornell University ecologist David Pimentel and graduate students Lori Lach, Doug Morrison, and Rodolfo Zuniga estimated the cost to the United States economy from alien species at approximately $123 billion annually–roughly the gross national product of Thailand.

By 2005, a report called the Millennium Ecosystem Assessment revealed that biological invasions had reached epidemic proportions. At least 170 alien species inhabited the Great Lakes, a single species of American jellyfish had wiped out twenty-six species of commercial fish in the Black Sea, and the Baltic Sea now hosted over a hundred alien invaders.

It is on islands, in particular, that these battles of attrition, which usually take place outside the human timescale, come into sharpest focus. On islands, the battles are swift, and the annihilations total and dominant species with no competition often proliferate to create multiple new species. Of the two thousand species of fruit fly around the world, about a quarter of them are found on the Hawaiian Islands.

In 1826, the H.M.S. Wellington accidentally introduced mosquitoes to the island of Maui. The mosquitoes carried avian malaria. Entire populations of native birds, which had no immunity to the disease, were wiped out or driven to higher altitudes. Feral pigs exacerbated the problem by rooting around the forest undergrowth and creating breeding pools of standing water for the mosquitoes. As a result, twenty-nine of the island’s sixty-eight native bird species have vanished forever.

As David Pimentel told the scientists attending the AAAS convention after presenting his findings, ‘it doesn’t take many trouble-makers to cause tremendous damage’.

No one could have imagined that island species could turn the tables on mainland ecologies. No one had even heard of Henders Island.

Elinor Duckworth Ph.D., Foreword,

Almost Destiny (excerpted with permission)