Dissertation Research: The Influence of Immigration on Local Community Structure: Experimental Tests of Theory in Two Beetle Communities

Arizona State University, Scottsdale AZ

Investigators

Abstract

Identifying the mechanisms that structure local communities is a fundamental goal of community ecology. Historically, ecologists invoked local processes to explain community structure, but equivocal evidence has broadened debate to include the potential importance of regional processes in structuring communities. Though experimentation has proven critical in resolving issues in ecology, theoretical and observational studies have, thus far, been the primary tools used to examine the effects of regional processes. I propose a series of novel experiments to test theories that span the range between local and regional control of diversity. Local process, metapopulation competition, and neutral community theories make predictions about the effects of immigration that are qualitatively different, mutually exclusive, and testable in the same immigration experiments. Using a laboratory system of Tribolium flour beetles and a field system of Cecropia petiole beetles, I will experimentally test these theories by simultaneously manipulating immigration regime and interaction strength (lab), and exposure to immigration and distance from colonization source (field). Though recently developed theory suggests regional processes can have a dominant effect on community structure, the theory must first be confirmed empirically if community ecology is to gain insight from the regional process perspective.