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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Population demography and plant-pollinator interactions of a federally threatened thistle, Cirsium pitcheri

Project Abstract: 
Pitcher’s thistle, Cirsium pitcheri (Asteraceae), is an herbaceous perennial plant endemic to the lacustrine dunes of Michigan and Wisconsin. Flowering begins in late June and continues throughout the summer until seed set in middle to late August. It has been shown that Pitcher’s thistle can set seed through self-fertilization. However, seed set is greatly improved by cross-fertilization provided by pollinators. I will study the population dynamics and pollinator interactions of C. pitcheri. I seek to understand (1) how population dynamics vary through time and (2) how the shifts in the pollinator community in response to climate change may impact populations of C. pitcheri. Both of these objectives will help us to better manage C. pitcheri populations in the face of climate change.
Years Active: 
2017
Methods: 
I will collect data from a long-term demographic plot (20- 10 m x 10 m plots) to update our 21-year dataset. Cirsium pitcheri plants will be categorized into four different stages: seedling, juvenile, vegetative, reproductive (Jolls et al. 2015). I will take measures of tap root diameter, leaf number, longest leaf length, plant height, and floral head number (>12 mm diameter) depending on the plant stage. These data will help us to construct stage-based matrix and integral projection models and to predict population viability. Individuals within the plant-insect visitor network of C. pitcheri will be evaluated for shifts in distribution using Maxent software. I will use climate and abundance data in the native range of the pollinators in order to construct a template of suitable habitat for C. pitcheri pollinators. I will then evaluate if there is a shift in suitable habitat under the forecasted climatic changes.
Funding agency: 
US Fish & Wildlife Service, Department of Natural Resources, Great Lakes Restoration Fund