Summary of final report:
Habitat loss and degradation has significantly impacted the prairie ecosystem. In Illinois, the loss of natural habitat and woody encroachment has caused reduction of native plant diversity and abundance. These changes in habitat structure can have both reproductive and physiological consequences for plants. In this study, we measured traits associated with reproduction (i.e., inflorescence length, the number of flowers, and fruit set) and photosynthetic ability (i.e., stomatal density and the number of leaves) to assess how changes in habitat structure could impact a rare plant, Synthyris bullii. This species is an Illinois state-threatened prairie perennial plant endemic to seven states in the Midwestern United States. Inflorescence length, fruit set, the number of leaves, stomatal density and genome size were measured in the two populations along the Mississippi River (Mississippi Palisades State Park [Pal-shaded habitat]) and two populations inland (Lost Mound [LoMo-open habitat]) in northwestern Illinois. Twenty individuals with a single inflorescence were randomly sampled from each population. Stomatal density data was determined in the laboratory by using the nail polish method and genome size by using flow cytometry. We found significant differences in stomatal density, fruit set and genome size between the two habitat types, and significant correlations between the stomatal density and reproductive traits. This study has identified three additional biological factors (i.e., reproduction, physiology, and genomics) affected by habitat degradation that could explain the rare status of Synthyris bullii.