Non-native species

“The two great destroyers of biodiversity are, first habitat destruction and, second, invasion by exotic species.” –E.O. Wilson

The spread of invasive species is a major factor contributing to ecosystem change and instability, ultimately leading to biodiversity reduction. Preventing non-native invasive species establishment has a much better success rate than trying to eliminate a species once it is established. At Apostle Islands NL, both aquatic and terrestrial species continually threaten the park. From microscopic organisms to large trees, the potential is always there for non-native species to invade and overtake fragile ecosystems that make the lakeshore a popular destination for hikers, boaters, and sightseers alike.

Park Ranger Japanese Knotweed
Park Ranger is attacked by Japanese Knotweed

Damon Panek


Non-native invasive species
Invasive species are non-native species which cause harm to the economy, environment, or human health. Invasive species:

• Cause more harm than good to the invaded ecosystem
• Have high growth and reproduction rates
• Are free from established predators, competitors, parasites or diseases in the invaded ecosystem
• Easily disperse/move from place to place

Many of these species can be transported via boats such as on hulls and in bilges, on clothing or gear that has come in contact with them, and even our firewood. For example, it is possible to transport zebra mussels from water body to water body through just a few drops of water containing larval froms. Spotted knapweed, a plant which has the potential to invade every beach on the Apostle Islands, can be transported and established through seeds carried in the soles of a shoe. Garlic mustard has the ability to threaten island forest communities. The gypsy moth and emerald ash borer can be easily transported on firewood.


What can be done?
“This is one environmental problem that we can do something about. I have seen the tremendous difference that even a few individuals can make in the battle to regain the land for native species.” -E. Czarapata

The best way to solve a problem is to prevent it from happening. Actions all visitors can take are preventative measures to keep non-native invasive species out of the Apostle Islands National Lakeshore. Whether kayaking, sailing, hiking, camping, fishing, or enjoying a picnic, paying attention can help keep invasive species out. Please do the following:

• Burn only dead and down firewood from the islands
• Clean, drain, and dry watercraft of all sizes
• Dispose of all fishing bait properly
• Clean all camping, boating, hiking, and other equipment prior to coming to the park
• Get involved in conservation efforts
• Educate yourself and others about invasive species

Kayaker cleaning his boat of invasives
Kayaker cleaning his boat of invasives

Neil Howk


Spreading non-native invasive species
“Give a weed and inch and it will take a yard” –Anonymous

The rapid spread of a non-native invasive species is usually due to a lack of predators, competitors, parasites, and disease in the invaded ecosystem. Invasive plants, animals, insects, or pathogens disrupt the interdependent balance that preserves an ecosystem’s biodiversity.

Human actions are the most pivotal factors in the spread of non-native invasive species. Check this list of the most common ways humans spread invasives during park visits.

• Transporting firewood with gypsy moth or emerald ash borer
• Moving zebra mussels or eurasian water milfoil on boat hulls/bilges/boat trailers
• Having spotted knapweed or garlic mustard seeds on clothing or footwear
• Camping equipment carrying soil infected with the sudden oak death pathogen
• Pet’s fur carrying purple loosestrife seeds
• Dumping minnows after fishing that are infected with viral hemorrhagic septicemia (VHS) pathogen
• Transplanting non-native plants from other areas
• Tire treads picking up buckthorn berries
• Landscaping with non-native species close to native ecosystems
• Bringing the next aquatic invasive from oversees in ship ballasts

Strive to be invasive free…
Your actions make a difference


Apostle Islands National Lakeshore non-native species reports

Last updated: March 17, 2017

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