Thesis Project:
Plant Performance in Prairie Restorations: Does Seed Source Matter?
Restoration managers use seed from various sources in their restoration projects. If the purchased seed is not of the local ecotype, land managers run the risk of poor establishment in the short-term and out-crossing between local and non-local ecotypes, genetic swamping and the loss of local genetic diversity in the long-term. However, using local seed may not be advantageous if local populations are inbred or maladapted to a changing environment. Moreover, purchasing seed is easier and can be less expensive than gathering seeds from local remnants. Although scientists have made great strides in addressing the potentially significant impact of seed source can have on restoration success, significant questions still remain. It is important that these be addressed.
In the summer of 2009 I began to study the relationship between plant performance and seed source. I focus on three warm season prairie grasses: Big bluestem (Andropogon gerardii), Side-oats grama grass (Bouteloua curtipendula), and Indian grass (Sorghastrum nutans). These perennial, long-lived prairie plants are dominant components of the prairie ecosystem and are widely used in restoration projects. Seeds were collected from each species from 26 sites in western Minnesota, including remnant prairie and state, federal and private restorations. I have counted the seeds, am currently performing a seed germination study, and will be planting a selection of the seeds in a common garden study in the summer of 2010. I will collect data on survivorship and growth and use these data to serve as the basis for an analysis of the performance of local versus non-local ecotypes in prairie restorations.
Independent Project:
Interspecific Co-flowering Prairie Plants Compete for Pollinators.
Pollen limitation is prevalent in many species, and can be especially worrisome in fragmented landscapes. Reproduction in the purple coneflower, Echinacea angustifolia (Asteraceae), which grows in small remnant patches of tallgrass prairie in North America, is pollen limited, but not pollinator limited.
Pollen limitation of Echinacea increases with isolation of individual plants, decreases with size of population, and has a strong negative impact on reproduction. However, pollinator visitation does not explain the reduced reproductive success. Wagenius and Lyon (2010), found that plants in the densest and largest populations of Echinacea receive fewer pollinator visits yet have greater reproductive success than plants in small isolated populations, which receive more visits but have decreased reproductive success. Among the many prairie plants pollinated by native solitary generalist bees, interspecific co-flowering plants may either enhance pollination by attracting more pollinators, or reduce reproductive success through competition or interference with compatible pollen receipt (Feldman 2008, Mitchell et al 2009).
During the summer of 2009, I worked with members of the Echinacea project to investigate whether the co-flowering species surrounding Echinacea influence pollinator visitation and whether invasive species within the floral neighborhood influence the number of pollinators that visit Echinacea.
Side-oats grama grass (Bouteloua curtipendula), pictured here, along with Big bluestem (Andropogon gerardii), and Indian grass (Sorghastrum nutans) are perennial, long-lived prairie plants. They are dominant components of the prairie ecosystem and are widely used in restoration projects. I am investigating the relationship between plant performance and seed source in prairie restoration. Specifically, I am testing for differences in survivorship and growth, between plants grown from local origin seed and plants grown from seeds gathered, or purchased, of non-local origin.
Another component of my study is looking at what influence, if any, the use of plugs versus seed has on seedling survival and establishment in restorations.
The entire Echinacea team helped me plant my three common garden plots. This one located at Runestone Wildlife Protection Area in Kensington MN. Pictured (back to front): Lauren Hobbs, Hillary Lyons, Laura Townsend, Kate Gallagher, Josh Drizin, Stuart Wagenius, and Gretel Kiefer.
