DISSERTATION RESEARCH: Assessing the relative effects of diversity, invader identity, nutrient input and disturbance on invasibility in low vs. high fertility grassland communities

Indiana University, Bloomington IN

Investigators

Abstract

Invasions of non-native organisms are ecologically disruptive and economically costly, and understanding the factors that promote biological invasions is an important area of ecological research. The variety of existing native species, the traits of invasive species, disturbances such as grazing, and nutrient inputs are all widely recognized as potentially important determinants of whether an ecosystem will be invaded. Yet there is much debate, and conflicting evidence, over which of these factors are most important. The debate stems in part from the tendency to study these factors independently of one another. This study will assist in advancing our understanding of biological invasions by examining all of these factors together, and asking how their relative importance changes with soil fertility, which is a major environmental gradient in nature. The study will be conducted using experimentally constructed plant communities modeled on native mid-western prairie grasslands of low and high soil fertility. Native plant diversity, disturbance and nutrient inputs will be systematically manipulated in these communities, and the communities will be exposed to an array of functionally diverse invasive species. This study will directly address a gap in knowledge of biological invasions by providing insights into the relative importance of key factors in promoting invasions. The insights gained from this study may enhance both the ability to predict and to manage invasions of grasslands and other communities. Furthermore, this study will be conducted at the Indiana University Research and Teaching Preserve, a resource that offers excellent opportunities for fostering both undergraduate research activity and communicating science to the local community.