Invasive plants ... for sale?

Author: Sue Lowe

Unfortunately, yes — but ND scientists hope to change that

SOUTH BEND — With all the publicity about invasive species of plants and animals, you wouldn’t think you could just go out and buy them.

Well, you can.

Notre Dame aquatic ecologists David Lodge and Reuben Keller were able to buy Eurasian watermilfoil, along with other things that concern them.

They and assistants bought water plants and animals from bait shops, live-food stores, nurseries, pet stores and biological supply businesses.They bought directly from local businesses within 200 miles of the southern edge of Lake Michigan and over the Internet from companies in the United States.

Keller said they found Eurasian watermilfoil three times.

Once, it was advertised and sold as itself despite its invasive nature.

Another business advertised a native milfoil that is not a problem. But, instead, the team got the Eurasian variety.

And, Keller said, they found it growing in a tank where water plants were stored at a local nursery.Eurasian watermilfoil is a lovely water plant. But it’s already in 24 percent of the lakes in Indiana, along with the St. Joseph River.

Lodge explained that it’s not as much of a problem in the river because of the current. In a lake it grows taller up from the bottom than native milfoils and other plants, spreading a canopy that blocks the sun and kills the shorter plants.

Keller said it also all dies off at once in the fall instead of in stages like the native milfoil. That means there’s a lot of decaying matter in the lake at once, taking oxygen and killing fish.

The Eurasian watermilfoil is just one of the reasons the researchers think we need more laws to control the importing of new plants and animals.

There is a federal law intended to protect the country from plants and animals we don’t want here.But there are only 19 aquatic and 72 land-based plants that are prohibited. And there are some 5,000 non-native plant species growing wild in the country.

“It’s almost like if we allowed any foods or drugs to enter the marketplace without any screening,” Lodge said. “They (plants and animals) may not be a direct threat to humans. but they are living and growing and spreading.”

The men don’t believe public education will work. That’s partly because a lot of the things aren’t always identified correctly, like the Eurasian milfoil they bought, thinking they were getting a native species.

Many of the plants and animals they bought were identified only by a common name, like “goldfish,” and many with scientific names that were wrong or not even real scientific names.

That makes it difficult for even educated consumers to know what they’re buying.Lodge said there are also religious practices that call for people to release some of the food they eat. And some Asian markets in large cities offer live food.

“Also, kids may bring them (a plant or animal) home from school after an experiment, get tired of them and release them,” he said.

Lodge said a lot of the businesses are selling water plants and animals because of water gardening.

“It’s (water gardening) growing at 80 percent a year,” Lodge said.

And unlike aquariums where imported plants and animals were once kept, water gardens are outside. That makes it easier for them to escape into the environment.“With the increasing globalization of trade, we see more and more species,” Lodge said. “As our ability to transport in bulk increases all kinds of species not in the western market before.”

Besides plants they know are invasive, the researchers also bought things like water hawthorn, water fern and eared watermoss, which they believe have the potential to become invasive in the Great Lakes area because they are already causing problems in other areas with similar or colder climates.

Another problem, particularly common with water plants, is other organisms hitchhiking along with what the customer buys.

“They’re just crawling with snails, insect larvae and little crustacea,” Lodge said. “The plants grow in outdoor ponds, and they’re colonized by all sorts of organism. Somebody goes out and grabs some to fill an order. You get a piece of the lake.”

“You can imagine pathogens or parasites,” he continued. “Some are from overseas and some are cultured here.”Lodge and Keller worked with the city of Chicago on a new ordinance that bans some invasive plants and animals, including Eurasian watermilfoil.

They are also working with other scientists and aquarium and water garden representatives in a group organized by the Indiana Department of Natural Resources’ Aquatic Invasive Species Program.

The two men wrote about their study, which was funded by the Illinois-Indiana Sea Grant, in the May edition of the journal BioScience.

The journal is on the Internet at .

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