Genetic Structure and Morphometric Variation among Fragmented Michigan Wild Rice Populations

Abstract

Wild rice (Zizania spp.) has ecological and cultural importance in the Great Lakes region, but has been declining due to habitat loss and fragmentation. We investigated the potential impact of bed area and isolation by distance on genetic structure, reproductive effort, and morphometrics in populations of two wild rice species (Z. palustris and Z. aquatica) in Michigan. Leaves were analyzed with Amplified Fragment Length Polymorphisms (AFLPs) and stem height, leaf length, panicle length, and number of male and female flowers were recorded. Despite finding multiple genetic clusters in each species, we found no geographic pattern to the clusters or any isolation by distance. Correlations revealed no associations between bed area and AFLP band diversity, nor bed area and morphometric traits. The number of female flowers was positively correlated with AFLP band diversity, demonstrating a possible impact of genetic diversity on reproductive effort. The results of this study suggest that habitat loss is not yet affecting the genetic diversity of wild rice in Michigan, possibly because of long distance dispersal vectors facilitating gene flow. Nevertheless, the ongoing decline of populations shows their need for protection and restoration, such as through more seeding efforts.