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Species at Risk

Pitcher's Thistle

Cirsium pitcheri

What is Pitcher's Thistle's status?

Pitcher's thistle is an endangered species according to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). This means that unless something is done to stop the plant's current decline, Pitcher's thistle could soon disappear from the Earth. In the United States, Pitcher's Thistle is considered to be threatened.

What is so special about Pitcher's thistle?

Pitcher's thistle habitat at Carter Bay on Manitoulin Island.
Pitcher's thistle helps anchor dunes and provides food for a variety of animals.
© Parks Canada / Dr. John Morton

Pitcher's thistle is an important part of the extremely fragile dune ecosystems of the upper Great Lakes.

Perhaps its most obvious value to the ecosystem is as food. A variety of animals feed on the seeds and leaves of Pitcher's thistle. There is also a species of moth that requires Pitcher's thistle for its survival.

Less obvious is the role Pitcher's thistle plays in providing a habitat for other dune dwellers. The plant is anchored by a long root (called a taproot). The taproot helps to hold the plant in place, and to draw water from deep below. By tapping deeply into the sand, Pitcher's thistle helps anchor the dune, creating a stable habitat for other plants and animals.

Species at Risk - Who Knew?

Pitcher's thistle flowers only once, when it is 2 to 10 years old, and then dies.

Why is Pitcher's thistle in danger?

The Great Lakes dunes where Pitcher's thistle lives are among the most rare and most threatened ecosystems in Canada . The dunes, and many of the species that live on them, have undergone significant declines during the past century. These declines are largely the result of shoreline development and recreational activities on the dunes and the beaches near them.

Many Pitcher's thistles die during the first few years of their life. If the plant is lucky enough to make it through this period, it must still overcome a number of threats if it is to survive long enough to bloom. Shoreline development, all-terrain vehicles and simply being stepped on are the biggest threats to Pitcher's thistle.