The main plant systems we use in our research are alders (Alnus sp.), various legumes (lupines, lima bean, and Scotch broom) as well as western sword fern. The herbivores that we work on range from invertebrates to mammals, while our experimental plant-associated microbes include both bacteria (e.g., rhizobia, Frankia, diverse root-nodule inhabiting bacteria) and fungi (mycorrhizal fungi, saprophytes, pathogens, and endophytes). Focusing on ecosystems in the Pacific Northwest as well as in the tropics (Costa Rica, southern Mexico), we further study the effects of anthropogenic disturbances on multitrophic interactions. By including both ecological and applied scientific approaches, our research aims to uncover the functional biology behind phenomena observed in nature and also to apply this knowledge for the benefit of society.