En 2012, un grupo de extraños molestos invadió el clima tranquilo de Connecticut. No eran gente de la ciudad de Nueva York que buscaba construir una segunda casa, sino insectos del tamaño de un centavo. Conocidos como barrenadores esmeralda del fresno, los escarabajos iridiscentes perforaron agujeros y pusieron huevos en los fresnos tan comunes en mi estado natal. Los insectos mataron a miles de árboles al comérselos durante cada etapa de su desarrollo larvario [fuente: DEEP ].
Los funcionarios ambientales estatales intentaron en vano detener la propagación de los escarabajos instituyendo medidas como poner en cuarentena la venta de leña. Sin embargo, librar al estado del barrenador esmeralda del fresno fue más fácil decirlo que hacerlo. Para julio de 2014, el escarabajo se había extendido a 38 ciudades de Connecticut y cinco de sus ocho condados [fuente: DEEP ]. El barrenador esmeralda del fresno, que vino más recientemente de Michigan, es solo una de varias especies no deseadas que han picado a Connecticut en los últimos años.
Although I have yet to see an ash borer, I gird myself each summer for my annual battle against another outsider — the Japanese beetle. I bait several socklike traps every July and watch them fill up like so many colostomy bags with the corpses of the beetle. As one environmental official told me years ago, Japanese beetles, the gypsy moth and other nonnative plants and animals are called invasive for a reason: They just won't let go.
Invasive species can be any type of living organism, as well as its seeds or eggs, that isn't native to a particular ecosystem. When I lived on Lake George in the Adirondacks of New York, the alien species du jour was Eurasian watermilfoil, a plant from Europe and Asia. It grew from one small patch on the southern end of the lake all the way to its northern reaches, crowding out native plants, choking water systems, entangling boat propellers and making it difficult to swim or fish. A few miles away in nearby Lake Champlain, another invasive species, the lamprey eel, literally glommed on to fish, including salmon, sucking the lifeblood out of them [sources: Lake George Association, National Wildlife Federation].
Whether plant, bug, fish or otherwise, invasive species come in all shapes and sizes. They're called variously alien species, exotic pests, nonindigenous species or nonnative animals, and they will not only wreck the environment but also destroy economies and make people sick, as the mosquitoes carrying West Nile virus do. They all grow and reproduce so quickly and aggressively that it is often hard to stop them [source: National Wildlife Federation].
