RELEASE: IMMEDIATE MAY 19, 1997 CONTACT: ELIZABETH LUCIANO #145-97
WEEDS CAN BE A SERIOUS THREAT TO THE ENVIRONMENT, SAYS UNIVERSITY OF MASSACHUSETTS BIOLOGIST
AMHERST, Mass. -- University of Massachusetts biologist Peter Alpert says that weeds can be more than just a backyard nuisance. Alpert would know: he's just been awarded a $49,000 grant from the National Science Foundation to film a documentary on the topic. The film, to be produced this summer in California, will be distributed to schools, colleges, and libraries, and will be available for broadcast on television.
"People think dandelions are weeds and they're right," says Alpert. "But they also think, 'What's the big deal?' Most people don't realize that weeds create serious ecological problems. They can transform your environment in ways you might not like."
In ecological terms, weeds are aggressive, non-native plants. In their native habitat, the growth of plants is generally checked by disease, by competition from other plants, or by being eaten by animals. In a different environment, some plants escape their natural enemies and launch what amounts to biological invasions, he says. "And biological invasions by foreign plants and animals are a major environmental problem." Alpert lists some of the problems weeds can create: some dry up water supplies, or make areas vulnerable to fire. Others crowd out native plants and eliminate habitat and food for wildlife. "We have to respect nature's potential to kick up ecological surprises," Alpert says.
The water hyacinth, a tropical plant from South America, is an example of a non-native plant taking over, Alpert says. In one season, without control, 25 plants, which you could encircle with your arms, can grow to two million plants, enough to cover two football fields. In the southern U.S., water hyacinths interfere with boat traffic and de-oxygenate the water, killing off fish.
Biological invasions can start all too easily, Alpert says. "All it takes is one seed of an aggressive plant that you carried by accident from someplace else." Sometimes it happens deliberately: gardeners may add an attractive-looking exotic plant to a flower bed. Purple loosestrife, brought to New England as a garden plant, is now invading the region's wetlands. In addition, a population of weeds can sit innocently for decades, Alpert says, and then suddenly begin to reproduce and spread widely.
And many people prefer some diversity in their environment, he adds. Alpert points to California sand dunes which are covered with European beach grass, rather than native plants, "which would make the dunes look like a flower garden," he says. "Once you realize what a place is supposed to look like, it's such a revelation. It makes you kind of sad."
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