LEECH LAKE DIVISION OF RESOURCE MANAGEMENT
FISH, WILDLIFE, AND PLANT RESOURCES DEPARTMENT
-PLANT PROGRAM-

WHAT WE ARE DOING ABOUT INVASIVE SPECIES...

This summer we are working with crews from the Minnesota Conservation Corps and the Chippewa National Forest to combat outbreaks of garlic mustard and other invasive plants. We continue to collect and raise leaf-feeding beetles in our greenhouse, which is located at the LLDRM complex in Cass Lake. These will be released at sites infested with purple loosestrife. The beetles specifically feed on this species and thereby control its spread. We are also working with the MN Departments of Natural Resources and Transportation to reduce invasive plants along roadsides and to restore native plant communities in these areas.

ABOUT INVASIVE SPECIES...

Invasive species are organisms not native to an ecosystem, into which they have been introduced as a result of human activity. They tend to displace native species, reduce biological diversity and wildlife habitat. Invasive species have contributed to the listing of 42% of the endangered and threatened species. Invasive species get here a number of different ways. Sixty percent of invasive species get here through horticultural activities, while thirty percent are introduced as conservation activities. The last ten percent are accidental introductions, like zebra mussels which were introduced in the ballast water of intercontinental ocean liners. When introduced into new areas they usually lack the biological agents (insects, diseases, etc.,) that control them in their native environment. Managing for invasive species usually means trying to bring balance to the ecosystem by using a number of different conservation tools. At the Plant resources department we use an integrated management approach to dealing with invasive species. An integrated approach to managing invasive species means using what ever combination of tools available that will do the job best.

One of the most prolific invasive species is purple loosestrife, which was introduced from Eurasia. It crowds out native vegetation and reduces wildlife habitat. Each plant can produce up to 2 million seeds per year and in its home range it has over 200 predators. However, here in the United States it has almost not native natural predators. In order to bring a balance to the ecosystem the Leech Lake Plant Resources has been raising Galerucella beetles which only consume the purple loosestrife.

Garlic mustard poses the greatest threat to the northern hardwood forest biological diversity. Garlic mustard crowds out native vegetation including maple saplings and traditionally gathered plants. Leech Lake Reservation in a cooperative agreement with the Forest Service and private land owners are working together to remove garlic mustard from the Reservation. During the summer of 2007 the Minnesota Conservation Corps was contracted to assist in pulling the garlic mustard. To date removal efforts have proven successful.

Purple loosestrife and garlic mustard are only two of many invasive species found on the reservation. Here is a list of other invasives found on the reservation:

• Rusty Crayfish
• Earthworms
• Plumeless Thistle
• Canada thistle
• Leafy Spurge
• Common or European Buckthorn
• Velvet Leaf
• Hoary Alyssum
• Spotted Knapweed
• St. Johnswort
• Wild parsnip
• White Cockle
• Common Tansy
• Common Cocklebur
• Purple loosestrife

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