Removing Invasive Frog-bit Colonies

Prevents its Spread Through Michigan

Removing invasive frog-bit from the Alpena Wildlife Sanctuary helped restore fish and waterfowl habitat, raised awareness of the potential dangers of invasive species, and taught people how they can avoid contributing to its spread.


Aquatic invasive plants have the ability to completely alternative ecosystems, with disastrous consequences for people, wildlife, and outdoor recre­ation. Recently, Michigan has seen the start of a new and potentially very harmful invasion, as colonies of European frog-bit have begun appearing in water bodies throughout northern Michigan such as the Alpena Wildlife Sanctuary, Saginaw Bay, and Munuscong Bay. Frog-bit is an aquatic plant that rests on the water, similar to a water lily. When invasive frog-bit establishes a new colony, it rapidly forms thick, dense mats of plant matter that are extremely hard to break through. The plant can quickly crowd out native plants by leaving no room for them to grow and by blocking sunlight. This can significantly reduce the presence of native fish and wildlife, as the invasive weeds do not provide them with their ecological needs. Fish and waterfowl can also become trapped within the frog-bit mats, as can any boats trying to traverse the afflicted waterways.

The Michigan United Conservation Clubs and Michigan Department of Natural Resources (DNR) have partnered to tackle this problem before it spreads out of control. The organizations removed frog-bit at the Alpena Wildlife Sanctuary to stop the spread of this colony and raise public awareness over this issue. Michigan United Conservation Clubs recruited volunteers, who were trained on what frog-bit is, how to recognize it, and how to effectively remove it. Teams of volunteers were then sent out in kayaks to hand-pull all the frog-bit they could find, with DNR employees leading teams throughout the wildlife sanctuary. A local conservation organization called Huron Pines set up mobile boat washing stations to demonstrate how people can avoid spreading the weed. Frog-bit is spread by boats moving through the dense mats and picking up some of the plants; if the boats (and the trailers used to transport them) are not properly cleaned prior to entering a new water body, they can introduce these plants and help establish a new invasive colony.  These efforts helped restore the area’s natural quality and improved habitat for native wildlife, while also increasing recreational uses of the area. MUCC and the DNR are trying to use this and similar events to spread the word and get people to take action before invasives spread out of control. The DNR is targeting Saginaw Bay and Munuscong Bay next, and both organizations may return to Alpena next year to guard against any potential “relapses.”

Resource Challenges Addressed

  • Lack of native habitat
  • Invasive species
  • Loss of native plant species


A boat is washed clean after using it to remove invasive frog bit

Boat washing stations were set up to demonstrate practices that avoid spreading frog-bit. Photo credit: Michigan United Conservation Clubs.

Results and Accomplishments

2,472 pounds of invasive frog-bit were removed from the Alpena Wildlife Sanctuary. These efforts helped restore the area’s natural quality and improved habitat for native wildlife. The event also improved recreational opportunities for anglers depending on a healthy native fish population and for boaters by freeing up waterways for kayaks and other watercraft. This project helped raise awareness of the potential dangers of a European frog-bit invasion and how people can avoid contributing to its spread.

Volunteers collect invasive frog-bit.

Volunteers paddled through the Alpena Wildlife Sanctuary on kayaks, removing invasive frog-bit by hand. Photo credit Michigan United Conservation Clubs.

Volunteers who helped clean up invasive frog bit

Volunteers were trained on how to recognize invasive frog-bit, and how to successfully remove it. Photo credit: Michigan United Conservation Clubs.