Anna Manson

Minnesota prairie ecosystems have been greatly impacted by habitat fragmentation, with only 1% of native prairie remaining. Habitat fragmentation isolates populations, and in plant species reliant on pollinators for reproduction and dispersal, this is especially harmful. Smaller, fragmented flora populations have a higher likelihood of mating between relatives. Mating between relatives increases threats of genetic drift and inbreeding, which can result in weaker progeny, reducing mean population fitness and potentially increasing extinction rates. However, the mechanisms by which habitat loss leads to population decline are poorly understood. In this study, we will use the model prairie plant, Echinacea angustifolia, to evaluate different relationships between population size, seed set, and genetic diversity. Reduced population sizes could affect plant reproductive success directly by reducing potential mates and limollinator dispersal and movement. Reduced population sizes could also indirectly affect plant reproductive success by reducing genetic diversity and limiting access to compatible mates. To test these alternative hypotheses, We will evaluate the direct relationship between population size and seed set, as well as the indirect relationship between population size and seed set, with genetic diversity mediating the relationship between the two. While this research is ongoing, this study will provide insight into which mechanisms lead to reproductive failure, which could aid in the establishment of future restoration strategies for Minnesota prairies and elsewhere.