Dr. J.D. Lewis addresses a variety of issues in community ecology and plant physiology, with an emphasis on the direct and indirect effects of humanson plants and plant communities. Current research projects include the effects of an invasive alien insect, the hemlock woolly adelgid, on forests in southern New York. A particular focus is the indirect effects of the adelgid on mycorrhizal fungal communities and on resource cycling. His lab is also researching the effects of urbanization on native and invasive plant species with a focus on the mechanisms regulating plant responses to the environmental changes associated with urbanization, including climate change, heavy metal pollution, and nutrient deposition. For example, he is examining the roles of plant age, phenology and size in regulating plant responses to environmental change. A central question these projects address is whether and how human beings influence the life cycle of plants.