Chamaecrista Fasciculata In Tallgrass And Sand Prairies: The Potential For Differential Responses

Abstract

Successful establishment of a diversity of native species has become an important goal for restoration site managers to achieve, however as seed sources for a species may occur in habitats with different abiotic and biotic characteristics. Consequently, seeds from different sources may vary in their success in a restoration. Chamaecrista fasciculata, a native prairie species, occurs in two divergent prairie types -tallgrass and sand prairies. Tallgrass prairies have a moist soil with dense vegetation; in contrast, sand prairies have a well-drained sandy soil with sparse vegetation. I propose differential selection acting on populations in these prairie types would affect their seeds success in restorations. Given the denser vegetation of the tallgrass prairies, plants must be capable of competing for light resources, thus I predict the plants from tallgrass seed sources have a better competitor tolerance and would be more successful in a reconstructed tallgrass prairie. To assess the effect of sand vs. tallgrass prairie seed sources, I conducted a greenhouse and a common garden study. In the greenhouse study, all plants from the three tallgrass and three sand prairies were reduced in height, biomass, and fruit production when exposed to a competitor (Schizachyrium scoparium). Further, sand prairie plants had greater fruit production while tallgrass prairie plants flowered and senesced earlier. In the common garden study, plants within the no trim treatment had a greater relative leaf area lost to herbivory in late seasonal measurements. However, my results found no evidence of tallgrass seed sources showing any greater competitive tolerance or relative success in comparison to sand prairie seed sources in the greenhouse and common garden studies. Still, different prairie types were found to differ in some observed traits in a greenhouse setting. Further study is necessary to determine if the observed differences in the greenhouse and the native prairies would impact restorations.