Carey's efforts are just one example of invasion biology, a science that straddles the fields of biology, ecology, epidemiology and pest control. The study of biological invasions has been driven by necessity. Pest species are piling up around cities, suburbs and agricultural areas, causing rising economic and ecological damage. They are usually impossible to eradicate once they take hold. If Formosan termites had been discovered early in New Orleans and their first nests destroyed, homeowners would have saved billions of dollars over the years.
Invasions are an enduring scientific riddle.
Science usually depends on controlled experiments, but invasions can't be reproduced in a lab. About 20 years ago, conservation biologists managing parklands started to examine the dynamics of invasions. They had to. As alien species infiltrated parks, they would supplant native species the scientists were trying to protect, foreshadowing problems that would soon spring up everywhere. Trying to understand how those species invaded and conquered the natives, conservation biologists sensed that pests were a kind of ecological evil twin to endangered species.