Graduate Student Association Department of Natural Resources

s Research Symposium January 2008 Graduate Student Association Department of Natural Resources Cornell University Mark Bain Hydro Peaking and Green Energy: St. Marys River, Ontario and Michigan Hydropower is a clean, flexible, and renewable energy source but its global benefits can come with significant local impacts and environmental losses. The use of hydropower facilities to track variations in electric supply and demand often causes significant environmental impacts from intermittent generation or hydro peaking. The St. Marys River connecting Lake Superior to Lake Huron was studied for assessing hydro peaking impacts. The river has the morphology of a complex strait, with substantial water turnover and current like a river, and changing water surface elevations from natural and human factors. Impacts of 43 hydro peaking cases were analyzed from North America and Europe. Reports of 149 specific impacts were tabulated to form a data set for relating hydro operations to impacts on downstream river environments. An existing impact significance scale was used to organize the hydro peaking impacts data into ratings spanning undisturbed or natural ecosystem status to severely altered environments with major loss of ecosystem structure and function. This analysis was used to specify a criteria for hydropower operations consistent with river conservation: a green energy standard for peaking hydropower. The standard was applied to hydropower operations on the St. Marys River. The standard allows more flexibility in hydro peaking operation than currently permitted and increased the efficiency and value of hydropower. New operating rules reduce the need to obtain electric power supply for other sources thereby increasing the contribution of clean and renewable energy. Bernd Blossey, Evan Cooch, Victoria Nuzzo and Amy Blair Multiple stressors in eastern forests: implications for management of deer, worms and other invasive species Eastern forests have undergone dramatic changes and many plant species now exist in isolated or small populations and are threatened, endangered or of special concern (TES). Threats to longterm survival range from habitat loss and fragmentation, to invasive plants, animals, and diseases, acid rain, nutrient deposition and climate change. Ideally, any plant management or of various threats would be informed by an analysis of the severity of a particular threat or of the cumulative threat posed by various stressors and how a particular plant species/population responds to management. Unfortunately, such guidelines are rarely available. In a new project, we will evaluate contributions of deer and introduced species (plants, earthworms, slugs, and weevils) and increased nutrient deposition on demography of TES plant species. We have evidence that earthworms may be the leading cause for plant invasions, at least in eastern forests in the Northeast. Deer browse on adult plants may lead to a collapse of the herbaceous layer and introduced slugs and weevils may prevent recruitment from the seed bank. While we have abundant evidence for the "ecosystem engineering" ability of deer or slug herbivory, plant or earthworm invasions, or nutrient deposition, our work will for the first time combine an assessment of these different stressors into a single study and model. Our working hypothesis postulates that a reduction of the deer herd will prevent declines of many native plant species (or allow their recovery). Simultaneously, we may see a reduced need for invasive plant