Web site would help state track invasive plants

University of Washington researchers say they're on their way to predicting which lakes and streams in the state are most vulnerable to invasive plants that can destroy native habitat.

The goal is to prevent outbreaks of nonnative weeds, which often are spread by attaching to boats that are moved from lake to lake, or by being dumped into state waters by people emptying the household aquarium.

"We are reactive in slowing the spread, but this would be more proactive," said Julian Olden, assistant professor in the University of Washington's School of Aquatic and Fishery Sciences.

Olden plans to create a Web site that maps the state's roughly 8,000 large lakes and would provide information on which foreign weeds are likely to invade each lake — if it hasn't happened already.

He recently received a $40,000 grant from the state Department of Ecology to develop the project.

The first phase will forecast invasions for three pesky species — Eurasian milfoil, Brazilian elodea and curly leaf pondweed. Olden said he hopes later to add more nonnative plants and animals to the interactive database.

He'll draw on existing data such as boat traffic on lakes, shoreline density and the water's chemistry to help predict which lakes are vulnerable to invasions.

Most statewide efforts to control nonnative aquatic plants have centered on responding to outbreaks. Resource managers use herbicides, divers with cutting tools, rakes and screens to try to control and kill invasive plants.

But state and county wildlife managers say the best solution is to keep nonnative plants from entering Washington lakes, or to catch foreign plants early before they have done too much damage.

"In a lot of ways, it's the public that keeps a watchful eye over when new invasions happen," Olden said.

Left unchecked, some invasive water plants can spread across entire lakes, making it impossible to swim, fish or canoe. The plants can also use up oxygen in a lake and disrupt the food chain as native plants, fish and birds struggle to survive.

Invasive plants survive so well out of their native waters because the usual bugs and diseases that naturally keep plants in-check don't exist in their new environment, said Kathy Hamel, aquatic-plant specialist with the state Department of Ecology. With little competition, invasive plants can quickly dominate lakes and streams.

Individual counties and state agencies survey and try to contain invasive weeds, but wildlife managers agree this Web site would be the first to systematically show where weeds might spread. It could especially useful for residents to monitor their nearby lakes if they know they are at risk, said Katie Messick, aquatic-weed specialist for the King County Noxious Weed Control Program.

Olden with the UW said the Web site should be ready by summer of 2010.

Michelle Ma: 206-464-2303 or mma@seattletimes.com