Indiana bans 28 invasive aquatic plants

Author: Anjanette Riley, The HELM (Illinois-Indiana Sea Grant))

Download the complete issue.

The fight against invasive aquatic plants in Indiana was broughtto local aquarium and water garden shops this fall with theapproval of a rule banning the sale of 28 aquatic plants that pose a high risk of invasion. These restrictions position Indiana as one of the most proactive states in the prevention of new aquatic
invasive plants and will help the state reduce the spread of known invasives.

“Trade is one of the strongest vectors for these species, and it is one that we can control,” said Reuben Keller, an environmental scientist at Loyola University Chicago. “Trying to reduce the risk of invasion through species in trade makes a lot of sense, even if we can’t guarantee that species won’t get into the state another way.”

The rule, which went into effect at the end of August, also makes gifting, bartering, exchanging, distributing, or transporting any of the 28 species illegal. To determine which plants imported for the aquarium and water garden trades posed the greatest threat to the state’s waterways, the Indiana Department of Natural Resources (IN DNR) relied on a risk assessment tool developed by the Aquatic Plant Working Group. The group was formed, organized, and facilitated by Illinois-Indiana Sea Grant at the request of IN DNR and included representatives from the aquatic plant industry, aquarium and water garden hobbyists, state agencies, academia, and nongovernmental organizations. They used information provided by University of Notre Dame researchers to develop a tool that evaluates a plant based on factors such as its history of
invasion, its ability to survive in Indiana habitats, and how difficult it is to control.

Many of the plants that made the list have been used in aquariums or water gardens in Indiana for years. Others have already been discovered in waterways throughout the state, sparking large-scale eradication projects. For example, efforts to remove the fast-growing weed Hydrilla verticillata from Lake Manitou have been ongoing for more than six years and cost the state millions of dollars. Hydrilla is believed to have entered Lake Manitou through trade.

“With this tool, if hobbyists and water gardeners became interested in a new plant, we could assess its invasiveness before it became widespread in trade,” said Eric Fischer, IN DNR aquatic invasive species coordinator. “We also plan to adjust this rule in the future to be more proactive as we assess new species.”

The success of the risk assessment tool in Indiana has sparked interest from officials in the Great Lakes region and at a national level. In fact, researchers at the University of Notre Dame were awarded a three-year grant from the U.S. EPA Great Lakes Restoration Initiative to develop risk assessment tools
for commercially sold fish, mollusks, crustaceans, reptiles, and amphibians. IISG’s aquatic invasive species outreach specialists are working with researchers to coordinate and facilitate regular working meetings with state and province resource managers to develop a single set of tools that can be used in each of the eight states and two provinces that make up the Great Lakes region.

“The Great Lakes are all interconnected. If one state bans a species but a neighboring state doesn’t, the ban is essentially meaningless in terms of keeping that species out of the lakes,” said Pat Charlebois, IISG aquatic invasive species coordinator. “The risk assessment tools we’re developing will give officials in the 10 jurisdictions the information they need to develop the consistent policies necessary to protect the Great Lakes.”