In support of his research activities over a five-year period, Dr. Scott A. Wissinger of the Departments of Biology and Environmental Sciences at Allegheny College (Pennsylvania) will receive Presidential Young Investigator Award funding. This work concerns complex biotic interactions at the interface of population ecology and community ecology. Specifically, the focus of the investigations is on multi-species competition, predation, and habitat selection processes among fish and dragonfly (Odonata) larvae in North American ponds. By manipulating replicate artificial ponds, effects of invading, migratory, large dragonflies on the resident smaller dragonfly species will be studied. Select undergraduate students, particularly seniors, at Allegheny College will have the opportunity to participate in this research. The second focus of the research addresses effects of acid precipitation on pond community structure; the study sites are a series of pristine high altitude (at 3500 meters) ponds located within the Nature Conservancy's Mexican Cut Nature Reserve near the Rocky Mountain Biological Laboratory (Gunnison, Colorado). Initially, surveys will be made to assess the relationship between alkalinity, and salamander (the top vertebrate predator) and invertebrate abundance. Results will then be used to design experiments for separating effects on prey from effects on predators. This award of funding will enable the investigator to complete development of an experimental pond facility, purchase maintenance and sampling equipment, and facilitate travel by personnel to remote study sites.