Ecological and evolutionary community assembly


I study how ecological communities assemble, with emphasis on historical contingency in community structure, ecosystem functioning, biological invasion and ecological restoration, using various methods (experimental, theoretical and comparative) and organisms (bacteria, protists, fungi, plants and animals) in collaboration with interdisciplinary colleagues.

Community structure often shows non-random relationships with the size, productivity, connectivity and other characteristics of localities. Using computer simulations and microbial experiments, I have found that these relationships depend on the history of community assembly, or the sequence and timing in which species join communities, at multiple spatial scales.

Recently, I am studying how historically derived variation in community structure affects the way ecosystems function. My current focus for this work is wood-decay fungi and their consumers. With New Zealand researchers, I am doing experiments to ask how assembly history interacts with top-down and bottom-up forces to alter fungal communities that drive nutrient cycling in ecosystems.

I am also interested in incorporating evolutionary diversification in community assembly theory, which has focused mainly on ecological, as opposed to evolutionary, dynamics. Our microbial experiments so far have shown that immigration history influences the extent of evolutionary diversification via ecological mechanisms such as competitive neutrality and indirect facilitation.

Although much of my work involves laboratory and theoretical methods, I maintain the same level of interest in conducting field research that addresses both fundamental questions and environmental issues such as biological invasion and ecological restoration. For example, I have been involved in a project on rat-induced community changes on New Zealand islands. Building on this effort, I am now working with collaborators to develop a project that will use numerous forest fragments created by lava flow in Hawaii. With this system, we seek to understand how the response of native plant and animal communities to non-native mammals varies with ecosystem size and landscape context.