Originally By Katie McQuaid

Faculty of Science

Hydrilla verticillate (hydrilla), one of North America’s most invasive species, was found for the first time in Canada. Dr. Rebecca Rooney, a biology professor, and members of her Waterloo Wetland Laboratory were surveying a secluded section of the Hillman Marsh Conservation Area in Leamington, Ontario, when they found the unexpected species. Upon review, the Ministry of Natural Resources and Forestry confirmed their findings. 

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Why is one little plant so worrisome?  

Hydrilla is an aquatic plant that spreads quickly and can take over entire wetland environments, threatening the diversity of plants and animals in ecosystems. Hydrilla can also limit recreational use of these areas because it can get tangled in boat motors, clog water-intake pipes and inhibit activities like swimming and paddling, hindering our ability to enjoy Ontario’s beautiful lakes and wetlands. 

“We hope to eradicate it before it can spread,” says Rooney, a leading expert in invasive species in Canada. “It’s currently in an area isolated from Lake Erie and other wetlands, which is good news. This will enable us to treat the infested area without impacting the larger water system.”  

Removing all hydrilla in Hillman Marsh could take several years, but Rooney and her team will be involved in the eradication efforts. The team plans to monitor the use of different tactics to remove the hydrilla from the area, such as administering approved herbicides and dredging.  

“We need to study how effective the different treatments are to control hydrilla so that if it is found again, we will have a removal plan ready that we know works,” Rooney says. 

Discovering this invasive species during survey work underscores the importance of environmental monitoring across the province and country. If researchers aren’t doing hands-on work in the field, they’re missing opportunities to catch infestations of invasive species before they are unmanageable.  

“Timing is so important because there's a tipping point with invasive species where we start to consider them established, and it changes from a goal of eradication to a goal of containment,” Rooney says. “Once you're in an established invasion, you're committed to ongoing management costs, and that eats into our conservation dollars that could be better spent fighting climate change and promoting habitat biodiversity.” 

Ontario spends millions of dollars a year on invasive species management to contain the invasive plants already present, and while scientists and researchers are doing the heavy lifting in that aspect, the public can also play a role in slowing the spread. 

“It’s important to follow the Clean, Drain, Dry method after being in the water,” Rooney says. “You should clean anything used, drain anything that was submerged and ensure it is completely dried before putting it into another body of water. Hydrilla can spread very easily by even a single tuber and it’s up to all of us to keep our water safe.” 

If you’d like to learn more, there are useful resources online to learn more about hydrilla and ways to reduce the impact of this invasive species.