Forests provide a broad range of services to people, including water purification, timber, food, carbon storage, and climate regulation. They are increasingly threatened by insect damage and disease. This research will document the impacts of climate change on herbivore damage to woody plant species, outbreaks of forest Lepidoptera, and the abundance of migratory songbirds. The project reaches beyond more traditional pair-wise interactions to examine multiple interactions affecting caterpillar abundances. It will contribute new information to a more thorough understanding of the factors affecting forest herbivores, thus informing both forest and bird conservation efforts.
Increases in greenhouse gases and atmospheric temperatures in response to human activities are well documented, as are the direct physiological effects of increasing temperatures. Warmer temperatures advance the phenology, or timing of events, of reproduction and development, for example. Individual organisms live within a web of interacting species, however, and changes in the abundance of a species with warming depend on how temperature affects its food, competitors, and predators. This research focuses on interactions among trees, Lepidoptera larvae, and their predators to examine both negative and positive effects of warming on forest caterpillars. It combines historical observations, experiments, and models to test how temperature affects the abundance of caterpillar consumers both through direct effects on caterpillar physiology and through indirect effects on predator abundance or food quality. Positive direct effects of warmer temperatures on the physiology of these consumers may, or may not, outweigh the expected negative indirect effects due to increased predation or decreased food quality. The research will significantly improve an ongoing dissertation project by examining the role of predators on caterpillar success and expanding the project to include a temperature gradient. The training of a talented, young, female scientist with thereby be improved.
