Project status update: Fire and fitness of Cirsium hillii

Illustration by Jeremie Fant

Illustration by Jeremie Fant

Cirsium hillii (Hill’s thistle), like Echinacea, is a native, self-incompatible, prairie species that grows in high, dry soils. However, Hill’s thistle is listed as a Species of Special Concern in Minnesota and little is known about how it responds to fire. We study effects of fire on the fitness of C. hillii plants at Hegg Lake WMA.  Burn and non-burn units were designated prior to an experimental fall burn conducted by the DNR in 2014. That year, we mapped 28 C. hillii plants (basal and flowering) in those plots.

Following the burn in summer 2015, there were two flowering C. hillii individuals. Team Echinacea assessed survival and collected tissue samples from plants for analysis by Abbey White, a MS student in Northwestern’s Plant Biology and Conservation Program. Abbey used microsatellite markers to describe patterns of genetic diversity across the Midwestern range of C. hillii and determine if inbreeding or clonal growth contribute to the low seed set observed in the region. So far she has seen evidence for a lot of clonal growth. This has a direct application to the restoration of C. hillii since the number of plants we see may not be representative of the number of genetic individuals in the population.

We will revisit plants annual to assess their survival and reproduction.


Start year: 2014

Site: Hegg Lake WMA

Overlaps with: fire and flowering at Staffanson Prairie Preserve



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