Food web structure influences community stability, nutrient cycling, and primary productivity. Spatial ecology, on the other hand, has identified the primary roles that patch size and connectivity play in determining the presence and abundance of species in patchy habitats. This project aims to bridge the gap between these research programs, using stable isotope analyses to elucidate how food web structure depends on patch size and context. As the ratio of heavy to light isotopes of nitrogen and carbon measure trophic position and the ultimate sources of species' biomass, the isotopic signatures of all species in a community can provide a quantitative measure of functional food web structure. Using a well-studied salt marsh arthropod community, this project will quantify the effects of patch size and connectivity on the diversity and redundancy of realized trophic positions and determine whether species' trophic positions are themselves functions of patch spatial context.
This grant provides a much-needed synthesis of food web and spatial ecology that leverages a novel application of stable isotopic analysis to understand resource flow in a heterogeneous landscape. In doing so, it provides integrative training for a female graduate student, as well as basic ecological knowledge of a sensitive, economically important ecosystem.
