Integrative Community Ecology Unit (David Armitage)

The goal of our unit is to determine the fundamental principles governing the assembly, dynamics, and functioning of communities and ecosystems.

We are a group of interdisciplinary scientists broadly interested in the origins and maintenance of biodiversity in natural ecosystems. We are especially interested in the causes and consequences of spatiotemporal variation in biotic interactions such as competition, predation, and mutualism. It is increasingly acknowledged that many ecological patterns – from local species co-occurrences to continental range limits – result from the joint effects of species’ physiological responses to their environments, the biotic interactions in which they are participating, and their abilities to disperse across the landscape. Guided by theory, we conduct field and lab experiments to develop and quantify these interrelationships. We ask, for instance, whether dispersal of obligate mutualists such as pitcher plant arthropods or nitrogen-fixing bacteria is limited by habitat configuration, and, if so, how this impacts the performance and distribution of their host plants. Reciprocally, using molecular tools and gnotobiotic cultures, we also investigate how microbial partners’ performance is influenced by variation in their host phenotype, genotype, or local environment.

We are also exploring feedbacks between communities and ecosystems. While we know that ecosystem processes such as nutrient cycling and productivity are set in part by the compositions of their local communities, the development of a predictive theory of community-ecosystem feedbacks has lagged. We use laboratory and field experiments to study links between community assembly and ecosystem function with the goal of predicting how critical ecosystem functions will be affected by species invasions and extinctions – both of which have dramatically increased in frequency during the Anthropocene.

Although the majority of our unit’s research is empirical and fundamental in nature, it remains highly interfaced with both theoretical and applied conservation fields. At OIST, we aim to cultivate a multidisciplinary research group that values diverse backgrounds and expertise in order to advance the science of ecology – hence the “Integrative” in our unit’s name!