Wild rice (Zizania spp.) is a historically important food source for animals and humans in North America. Native American communities and ecologists struggle to understand reasons for its recent decline over portions of its geographical range and to develop suitable restoration strategies. A need exists to have a reliable method of estimating its past distributions based on lake sediments. This project will examine methods of reconstructing the geographic distribution of wild rice by comparing a modern plant macro- and microfossil collection from the region with data from lake cores, in which evidence of wildrice presence had been postulated based on pollen data. Geographically the area of study will focus on northeastern and central Minnesota, west of Lake Superior and south to Lake Mille Lacs. This region is chosen because it is near a northern limit of the present northern wild rice distribution and has a good coverage of available dated lake cores. Modern plant samples of four extant Zizania species (three in North America and one in Asia) will be examined under light and SEM microscope for presence of diagnostic phytoliths and grass cuticles. Modern sediment samples will be taken from a range of lakes, where wild rice is present today to assess modern range of microfossil distribution within lakes of different size and configuration. The dataset will be used to reanalyze six existing lake cores that had been dated and analyzed for pollen, in which spikes in pollen abundance had been interpreted, but never proven, as spikes in wild rice abundance. Additionally three to six new cores will be collected from lakes where wild rice is currently present or is believed to have existed based on archeological evidence to produce a point map of past distribution and abundance of wild rice in the study area since the late glacial to present (approximately 15,000 years before the present to today). <br/><br/>This study will develop a new and simple method of estimating presence and abundance of wild rice in lake sediments using simple coring devices and a light microscope. It will be a first-of-its kind systematic effort to look for distinguishing characteristics of Zizania and Leersia silica micro/macrofossils in lake sediments and some other wetland grasses that occur in the Great Lakes bioregion. This study will benefit archeologists, ecologists, and biogeographers working on wild rice restoration by providing a new quick way of independently verifying past presence of wild rice in stands in a lake. The results will be broadly disseminated via publications, web archive of images, presentations and workshops to natural resource professionals and Native American tribal representatives. It will further train one graduate and two undergraduate students (the latter from Native American background) with a new method of rapid wild rice analysis in sediments. The dataset will be of significant benefit to the paleoecological and archaeological communities in the U.S., Canada, and Asia.
Detecting Wild Rice in Lake Sediments by Phytoliths and Cuticle Analysis: A Pilot Study in the Great Lakes Bioregion