This research investigates how inter- and intraspecific genetic variation, environmental variation, and their interaction influence the structure and function of ecological communities (e.g., insect diversity, trophic interactions) and ecosystems (e.g., litter decomposition and nutrient cycling). Our earlier work focused on riparian cottonwoods in the western U.S.A., and was conducted in collaboration with the Cottonwood Ecology Group centered at Northern Arizona University. Our current work focuses on WisAsp, a genetic mapping population of aspen (Populus tremuloides) near Madison, WI. The goal of this work is to identify the genomic components that underlie genotypic variation in aspen traits (chemistry, phenology, morphology) and in associated insect communities. Genomic work is being conducted in collaboration with Pelle Ingvarsson (Umeå Plant Science Centre, Sweden).