Background/Question/Methods There is a long running debate between the appropriateness of using grass cultivars that have been developed as forage / soil erosion control crops when restoring or augmenting native grasslands. A field study was established in March 2006 to test whether differences within multiple dominant species widely used in community re-assembly acts as a filter on community assembly and scales to affect ecosystem function. This experimental design is unique as it provides replicated experimental community assemblages that differ in source (cultivar vs. wild collected) of the dominant grasses. We are using this experiment to determine how population source of the dominant grasses affects the genetic structure of the subordinate species. The Citadel Plant Ecology Laboratory (CPEL) is using inter-simple sequence repeats (ISSR) DNA markers to characterize differences in population genetic structure of one of the dominant planted grasses (Sorghastrum nutans) in this experiment and two subordinate forbs (Chamaecrista fasciculata, Silphium integrifolium) growing in the matrix of wild collected and cultivar dominant grass.
Results/Conclusions Multiple response permutation procedure (MRPP) analysis indicate significant differences (T=-3.131, A-0.053, P =0.011) between Chamaecrista fasciculata growing in two plots planted with cultivar grasses versus this same species growing in two plots planted with native collected grasses. UPGMA cluster analysis based on Jaccard’s similarity also showed that Chamaecrista fasciculata growing in the native grass communities were more genetically similar to each other than they were to Chamaecrista fasciculata growing in the cultivar grass communities. We will compare and contrast genetic structure differences of an annual (Chamaecrista fasciculata) and perennial (Silphium integrifolium) native species growing in a background of wild collected and cultivated varieties of the dominant grasses.