Soil Biodiversity and Sustainable Biofuels
The U.S. Energy Independence and Security Act of 2007 mandates production of 16 billion gallons of cellulosic ethanol by 2022, encouraging growers to consider warm season grasses such as switchgrass and miscanthus for cellulose feedstock, especially on marginal lands. However, management practices such as fertilizer applications may reduce many of the ecosystem services provided by these grasslands, especially those influenced by belowground organisms. In collaboration with Dr. Kay Gross and Dr. Karen Nikolakakis (Michigan State University), I am evaluating the effects of fertilization on arbuscular mycorrhizal fungi (AMF), and the direct and indirect consequences that these effects have on productivity, pathogen loads, crop drought tolerance, and soil carbon in perennial switchgrass biofuel systems associated with the Kellogg Biological Station (KBS) Long Term Ecological Research (LTER) site and Great Lakes Biofuels Research Center (GLBRC) located in Michigan. (http://lter.kbs.msu.edu; http://lter.kbs.msu.edu/research/areas-of-research/biofuels/). This work is currently funded by DOE and USDA.
Plant-Fungal Symbioses and Climate Change
In collaboration with Dr. Jennifer Rudgers (University of New Mexico), I am conducting research on mutualistic endophyte fungi (EF) and AMF in Great Lakes sand dune plant communities dominated by the grass Ammophila breviligulata. Dune systems provide unique opportunities to examine the role of microbial mutualisms as they are one of the few natural systems where plant and soil communities develop from initially sterile conditions. Fungal mutualists can help infected plants in stressful environments by increasing resistance to herbivores, drought tolerance, and nutrient uptake. These symbionts can additionally alter competitive interactions between species, and so may have important impacts on dune invasion dynamics. Further, dune restorations provide ideal opportunities to study how changes in AMF and EF affect plant community structure, as restoration activities often alter microbial biota unintentionally. We currently have a large climate-change experiment at Leelanau State Park, studying the ability of endophytes to mitigate impacts of climate change in this region.
Community and Ecosystem Impacts of Invasive Plants
Through a 10 year collaboration with The Nature Conservancy (TNC) in Michigan and the National Park Service (NPS) at Sleeping Bear Dunes National Lakeshore, my lab has evaluated the local and landscape-level effects of the invasive plant species Baby’s Breath (Gypsophila paniculata) on plant and insect diversity aboveground, and mycorrhizal and nematode diversity belowground. In some dune areas, G. paniculata comprises 80% of all vegetation, and managers are concerned that G. paniculata creates problems for the dunes by overstabilizing a typically wind-disturbance driven habitat and possibly out-competing native species. Management includes both physical removal (via crews with shovels) and chemical control (glyphosate) when conditions are appropriate. My work has shown that management has been very effective at reducing Gypsophila populations. Despite having little effect on plant, insect, or nematode alpha diversity, management is increasing plant and nematode beta diversity at local scales.