By Buddy Gough
The invasion and spread of non-native plant and animal species cost the country billions annually in losses to agriculture, forestry, fisheries and waterways maintenance.
If that number seems incomprehensible, forget the dollars and consider the small example of the invasion of brown tree snakes on the distant island of Guam. There, the slithering invaders, which were introduced accidentally as stowaways from New Guinea on ships during the 1950s, have caused the extinction of a dozen native bird species—or two for every decade they’ve been on the island.
Unchecked by the natural constraints of their native environments, the eight-foot serpents exploded on Guam to population densities approaching 40 per acre in certain areas. Finding easy pickings among the island’s native bird species, the nocturnal predators have decimate native bird species, including some found nowhere else in the world.
The invasion of brown tree snakes has extended to Guam’s harbors and airports where they hide in crates and other materials commonly shipped by sea or air. As a result, individual specimens have shown up at far-flung international ports, including Texas.
Hawaii is now considered to be under the most imminent threat of invasion. As a measure of the threat, the plans for control and eradication involve dozens of international, federal and state agencies.
Yet, the reptile represents only one of thousands of invasions of non-native plants, animals and insects that are occurring around the world at an unprecedented rate and scale. The Nature Conservancy notes that the United States alone has seen more than 4,500 foreign species gain a foothold or take root over the past century.
Although the brown tree snake has long been considered non-venomous, once established in areas without predators, it can grow to lengths that make it dangerous to children. As such, it has been reclassified as mildly venomous in some parts of the world. Texans are urged to be vigilant when monitoring for the brown tree snake or any of the other invaders that threaten the native plants and animals of the Lone Star State.
For more information about The Nature Conservancy's work in Texas, including other invasive species we help control, visit nature.org/texas.February 11, 2011