QEIB: Island Biogeography and Metacommunity Dynamics of Food Webs--Theory and Experiments in a Model System

University Of California-Davis, Davis CA

Investigators

Abstract

Ecological communities are comprised of organisms that assemble over time by the colonization of a local site from the surrounding region and by subsequent species interactions that determine the fate of species. The sequence of such colonizations and subsequent changes in community composition are termed "community assembly". Because ecological communities are not static, understanding assembly is central to successfully conserving biodiversity. Unlike previous work, this project studies assembly in patchy landscapes where both within-patch assembly and between-patch movement are expected to be important. It uses a recently-developed mathematical approach and a highly-tractable laboratory system consisting of protozoa in microcosms to understand transitions in species composition. These approaches represent powerful tools for developing and testing ecological ideas that can then be tested in the field systems we wish to conserve. The approach consists of experimentally identifying all persistent species combinations and determining the frequency of invasion by previously absent species. Experiments will test the effect on the frequency distribution of species compositions of between patch movement, whether species are native or nonnative, and the distance over which species are moving in landscapes. Modeling such transitions will produce a precise, testable, general theoretical framework that can be applied to studying community assembly in many systems. The problems addressed are key to conservation of biodiversity, management of invasive species, and habitat restoration.