The Formation and Influence of Spatially Structured Trophic Interactions in Primary Succession at Mount St. Helens

Washington State University, Pullman WA

Investigators

Abstract

Research will examine on how trophic interactions (i.e., feeding relationships) influence succession using a natural biological invasion in which a native plant (lupine) and its associated specialist herbivores are recolonizing Mount St. Helens. Efforts will quantify the extent to which spatial variation in the dynamics of trophic interactions influences the pace and pattern of primary succession. This will afford a unique opportunity to unravel complex connections between consumer-resource interactions over a large landscape. Indeed, the Mount St. Helens landscape provides a unique but fleeting opportunity to study an herbivore-mediated transition between successional phases. Three questions will be answered in detail. First, do resource or consumer gradients associated with patches of lupine drive spatially structured herbivore dynamics during primary succession? Second, do lupines and lupine herbivory affect the community dynamics of plants? Third, how is this complex tritrophic reinvasion progressing and influencing primary succession? The detailed investigations will constitute a key case study of how sequential spatial advance of components of a parasitoid-herbivore-plant system can influence the dynamics of species change at the landscape scale of analysis.