Biology colloquium to focus on invading species


CORVALLIS - The global threat to biodiversity posed by invading species will be examined at the 61st annual Biology Colloquium at Oregon State University on April 12, titled "Biological Invasions! The Quiet Global Change."

The program will focus on the economic and ecological havoc caused by nonnative invasive species, like the blackberries that must be dug out by the roots, the opossum in your garbage can, or the hitchhikers customs officials try to intercept when they ask if you're carrying any fruit or vegetables.

The event will be held at the LaSells Stewart Center and is free and open to the public, but registration is required. For more information, visit the web site or contact Christi Sheridan at 541-867-0367 (e-mail: christi.sheridan@hmsc.orst.edu).

The colloquium should be of interest to gardeners, fishing enthusiasts, bird watchers or anyone interested in ecological protection, organizers say.

OSU began hosting an annual biology colloquium in 1940 as a forum for public discussion of research topics relevant to the academic mission of the university and the lives of students and citizens.

An invasive species, experts say, is a newcomer that isn't a good neighbor. For instance, the brown tree snake is implicated in the virtual disappearance of native songbirds on Guam. The gypsy moth made lunch out of Pacific Northwest forests. Nutria today chomp their way through significant portions of public marshland in Chesapeake Bay.

Starlings, introduced by homesick European colonists, compete with regional songbirds for food and nesting areas across the U.S. And zebra mussels, such effective filter feeders they can starve neighboring native clams to death, became known for their skill at plugging pipes.

In the Pacific Northwest, invasive species include the nutria, the European green crab, and a plethora of plant invaders that choke out native vegetation and in some cases alter habitat. There's also the incredibly prolific and tenacious Himalayan blackberry, various crop weeds such as leafy spurge and cheatgrass, and the sunny but sneeze-inducing Scotch Broom, implicated in historical fires that swept through Bandon, Ore.

All of these invaders live in ecological balance in their native habitats. But lacking natural controls, their exploding populations can rupture the ecological balance of their new home, wiping out regional species in the process.

Many invasive species get a foothold due to human intervention, scientists say.

New species often get introduced deliberately by homeowners ordering plants or bringing pets or plants home from trips; by hunters wanting a favorite game animal or a new fishing challenge; by authorities pressed to solve problems ranging from erosion to insect infestations. Some species are simply hitchhikers, tagging along with humans and our cargo as we hopscotch around the globe.

According to the Nature Conservancy and U.S. Department of Agriculture, invasive species have contributed to the decline of more than 400 endangered and threatened species in the U.S. Given the pressures on remaining ecosystems, some worry that invasive species may even alter the course of evolution.

Eradicating invasive populations once they are established can be so difficult and damaging to native neighbors that every state in the nation has been asked to develop a formal method of preventing, identifying and stopping invasions before they take hold. President Clinton created a national Invasive Species Council last February to oversee that effort.

Countries use trade policies to attempt to control the importation of diseases and unwanted species. Agriculturists and natural resource managers frequently must rely on chemical controls for established invasions, and pass along to the consumer the cost of herbicides and crop losses.

The financial costs are staggering.

The European gypsy moth is thought to have cost the U.S. economy $764 million, according to the U.S. Department of Agriculture. The zebra mussel alone may cause $5 billion in damages by the year 2002. And the annual impact of nonnative weeds on the U.S. economy is roughly $13 billion.

Websites and other resources exist to inform gardeners, outdoors lovers and travelers about the problem and how to avoid adding to it. Visit the links page of the colloquium website or contact the Nature Conservancy, the Native Plant Society, the National Park Service, Oregon Sea Grant, or your county Extension agent.