Invasive Species

Prevention is key!

The Glen Lake Association strives to prevent, monitor, and control or eradicate both aquatic and terrestrial-based invasive species. We operate a free boat wash at the Glen Lake launch site to remove invasive aquatic plants and animals from watercraft. We perform drone surveys to monitor the land and the water for the presence and spread of invasive plant species. You can help stop the spread! Learn about invasive species that pose a threat to the Glen Lake/Crystal River Watershed.

what is an invasive species?

An invasive species is defined as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.”* Invasive species can be aquatic (i.e. water) based or terrestrial (i.e. land) based and may be plant or animal in nature.

the problem with invasive species

Invasive species pose a significant threat to Michigan’s aquatic and wetland resources. Invasive species will:

  • Reduce overall plant and animal diversity
  • Destroy critical biological resources such as fish nursery habitat
  • Simplify natural communities (as opposed to diversifying)
  • Reduce property values
  • Restrict fishing, boating, and other recreational opportunities
  • Require significant expense to control their spread


 Please be on the lookout for these invasive plants and animals. If you spot one, take a photograph and document its location. Then contact the Glen Lake Association immediately. Please do not try to remove the species on your own, as improper techniques can be detrimental to water quality and may cause the species to multiply.

Invasive Aquatic pLANT species

Curlyleaf Pondweed invasive aquatic species

Curlyleaf Pondweed

Photo by Chris Evans, University of Illinois,
eurasian watermilfoil

Eurasian Watermilfoil

Photo by Barry Rice,,

Invasive Terrestrial PLANT species

yellow iris invasive species up close

Yellow Iris

Photo by John M. Randall, The Nature Conservancy,
coltfoot plant up close flowering and leafing


Photo by Jan Samanek, Phytosanitary Administration,
purple loosetrife invasive species

Purple Loosetrife

Photo by Becca MacDonald, Sault College,
Flowering phragmites invasive grass species


Photo by Leslie J. Mehrhoff, University of Connecticut,
garlic mustard invasive species

Garlic Mustard

Photo by Rob Routledge, Sault College,

Invasive Animal species

round goby invasive fish species

Round Goby

Photo by Center for Great Lakes and Aquatic Sciences, University of Michigan,
invasive bird species European Starling

European Starling

Photo by Lee Karney, US Fish and Wildlife Service,
quagga mussel invasive species up close

Quagga Mussel

Photo by Mike Quigley, NOAA,
zebra mussel invasive species

Zebra Mussel

Photo by Amy Benson, U.S. Geological Survey,


Help stop the spread!

Yellow Iris has spread in the watershed over the past several seasons and we need riparians help in eradicating this plant. Although they appear lovely, problems arise when the seed pods mature, arch over the water, split open, and disperse. Seeds can travel far and wide on the waters of our lake, washing into crevices, lodging against berms, and taking root. Over time, they can create a dense mass along the shoreline, choking out the native plants that keep our local ecosystem healthy.

Please let us know if you notice Yellow Iris on or near your property, and we will help you remove it!

preventing aquatic invasive species

The Boat Wash:  Our first line of defense!

boat wash on glen lake paddleboard

Did you know?

An invasive species’ primary means of entry to a lake or river is as a hitchhiker on a boat, jet ski, or kayak. If your watercraft or equipment has been in another lake or river, please be sure to use our free boat wash before you launch into Glen Lake.

All it would take is for one quagga mussel egg or fragment of invasive plant attached to the bottom of a newly launched boat to trigger an invasive species infestation in Glen Lake.

To protect against this, the Glen Lake Association operates a boat wash and inspection program at the MDNR, Day Forest Rd. public launch on Little Glen Lake. This heated pressure wash system removes larvae, eggs, and plant fragments which can survive anywhere water accumulates on or in watercraft: on the hull, in the motor’s cooling system, in a bait box, or on equipment such as wadders, waterskis and wakeboards.

Without the GLA Boat Wash, Glen Lake would most likely be facing a costly infestation of aquatic invasive species (AIS) right now. Other nearby lakes are spending hundreds of thousands of dollars in an atttempt to control invasive aquatic plants. Thanks to the Association’s Boat Wash Program, our lakes remain largely free of invasive species. Please help us keep it that way by making a donation to the “Keeping It Blue” Boat Wash Campaign today.

preventing TERRESTRIAL invasive species

students help remove invasive species from shoreline

Invasive plant eradication and control efforts have been underway along our shorelines for several years. Our strategies for controlling land-based, (i.e. terrestrial) invasive species include:


  • Performing surveys by boat, foot, and drone to assist in monitoring and documenting new and known infestation sites using mapping software
  • Deadheading early Spring blooms to prevent seed plant spread, and removing seed pods of plants that have already flowered.
  • Protecting and planting native plants that guard our waters with their deep rooted soil stabilization and nutrient absorption abilities.
  • Eradicating discovered invasive plants through careful digging up of small infestations and determining best practices for destroying larger populations

The glen lake association is prepared to fight EURASIAN WATERMILFOIL

Prevention of invasive species is one of the Association’s top priorities. We have a working plan in place to eradicate and/or control identified species so that they don’t spread and evolve into costly control programs. For Eurasian watermilfoil (EWM) in particular, the Glen Lake Association has developed a rapid response protocol that we believe will ultimately allow us to maintain the goal of eradication. As watershed residents and visitors, you can rest easy knowing that the GLA has a plan in place.

Our eradication plan includes the use of aerial drone survey to identify possible infestations followed up with onsite verification by scuba diver. Confirmed areas of EWM will be covered with biodegradeable light blocking barriers that starve and then kill the plant. No need for expensive chemical treatment or labor intensive and unreliable manual removal.

The success of this plan depends on rapid identification and response to the presence of EWM in our lakes, and would fail if EWM were to grow undetected for months. It is crucial that we remain vigilant in our monitoring efforts, ready to react quickly if necessary, and prepare financially to support any required eradication efforts.

Support our watershed fund to help us prepare for emergencies

Our Watershed Fund is endowed to support special water quality initiatives and unexpected water protection work. Help us ensure the health of the watershed by making a gift today.

What can you do to help prevent invasive species?

You can be part of the solution!


  • Familiarize yourself with the known and potential invasive species in the Glen Lake/Crystal River Watershed


  • Always utilize the Boat Wash before launching your boat or PWC
  • Ensure you thoroughly wash other smaller watercraft (i.e. kayaks, paddleboards) as well as equipment (i.e. waterskis, wakeboards) before placing these items in the lakes or river
  • Plant native plants along your shoreline or stream bank, as well as throughout your landscape, to help diversify the landscape and keep invasive plant species at bay.


  • If you see something questionable, ask the GLA to come confirm your findings or email a photo to
  • Don’t pull out an invasive plant without first consulting with the GLA, as fragmentation may lead to spread
  • If you find an invasive plant species for sale at local nurseries or garden centers, ask them to please stop selling it


  • Volunteer to monitor, map, or assist the GLA in removing invasive species
  • Donate to the GLA to help fund invasive species prevention and eradication efforts
*Source for the Definition of Invasive Species: The National Invasive Species Management Plan