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US Fish & Wildlife Service FieldNotes

East Lansing Biologists Search for Invasive Species Damage on Threatened Pitcher's Thistle

Region 3, August 15, 2012
East Lansing Field Office biologists Emily Westbrook, left, and Tameka Dandridge collect damaged seed heads of Pitcher's thistle in northern Michigan.
East Lansing Field Office biologists Emily Westbrook, left, and Tameka Dandridge collect damaged seed heads of Pitcher's thistle in northern Michigan. - Photo Credit: n/a

Biologists from the East Lansing Ecological Services Field Office spent three days in August at Wilderness State Park in northern Michigan to search for signs of damaged seed heads on Pitcher's thistle, a federally listed species. A non-native species of weevil, which was introduced to fight non-native invasive thistles (such as Canada thistle and bull thistle), had first been reported on Pitcher's thistle in the park at the end of July. Because the extent of the threat that non-native weevils pose to Pitcher's thistle is currently uncertain, ELFO biologists, with assistance from researchers at East Carolina University, collected Pitcher's thistle seed heads with signs of damage to begin to assess the level of weevil infestation. More than 150 seed heads were collected and sent to the Chicago Botanic Garden, where botanists will analyze the seed heads for weevil presence. Pitcher's thistle is a Great Lakes endemic that occurs in dune ecosystems and is listed as threatened under the Endangered Species Act.

Contact Info: Barbara Hosler, 517-351-6326, barbara_hosler@fws.gov