Saving an emblem: Mingan thistle

Sowing Mingan thistle
Credit: Parks Canada / C. Bélanger
Sowing Mingan thistle
  • Sowing Mingan thistle
  • A flowering Mingan thistle
  • Filets pour récolter les graines de chardon de Mingan
  • Sauvetage de plants de chardon ensevelis par une tempête
  • Rosette chardon de Mingan
  • Le chardon de Mingan vit sur la haute plage
  • Semis de chardon de Mingan âgés de quelques jours
  • Plants de chardon de Mingan cultivés à la pépinière du Biodôme, Jardin botanique de Montréal.
Saving an emblem: Mingan thistle

An isolated plant, after a long journey

Mingan thistle (Cirsium scariosum var. scariosum), now a threatened species in Quebec, was named in 1924 by Brother Marie-Victorin. In Canada, it is found only in the Mingan Archipelago National Park Reserve, on Quebec’s North Shore, and in some rare alpine prairies in the far southern reaches of Alberta and British Columbia. The two populations are about 3,500 km apart – the plant likely travelling along the glaciers to the Mingan archipelago during the latest ice age, 10,000 years ago.

Facing many threats

In the Mingan archipelago, this species is found where the forest meets the shore, a habitat highly influenced by the sea. With global warming, the sea rarely freezes any more, exposing the shoreline to high waves during storms. Most of the sites where Mingan thistle grows have been drastically affected in recent years. Shorelines have been eroded and plants have been buried under as much as 50 cm of sand, stones, wood, other plants and debris.  They are also threatened by other factors, such as the low number of flowering plants, varying from just 2 to 23 depending on the year. As a result, there are very few new plants to replace the ones that perish.

Working together to save Mingan thistle

Mingan thistle is a perennial that flowers only once and then dies. It takes an average of nine years to flower, but some plants can survive for over 20 years. Since 1995, it has received special treatment, as each plant has been monitored individually. That’s right, each one has a numbered tag, making it possible to track their ages and survival rates.

After the population plummeted by more than 70% between 2011 and 2017, a committee of experts from different organizations was struck to determine how best to help save the species. Suggestions included clearing debris away from the plants after storms, planting seeds, seeking new suitable areas for the species, and producing plants and seeds outside the park. The Gosling Institute for Plant Preservation at the University of Guelph is currently developing in vitro methods for growing the plant. Saving a species takes teamwork!

Sowing hope

Efforts to re-establish Mingan thistle are also drawing on the expertise available at the Biodôme, where the emphasis is on developing growing techniques. Our experts hope to produce seedlings that can be reintroduced in the wild, so as to boost the number of seedlings in existing colonies or create new colonies in sites sheltered from storms. The 2017 season produced excellent results. The nursery now has more than 40 plants that could flower and produce seeds starting in 2019. If everything goes according to plan, seedlings will be planted in some suitable sites this fall. Things are definitely looking up for Mingan thistle!  


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