Habitat fragmentation as a process: how habitat context influences the effects of eelgrass loss on epifaunal community structure

San Diego State University Foundation, San Diego CA

Investigators

Abstract

In this research project, the investigator will carry out a set of field experiments to determine whether the effects of experimentally fragmenting seagrass habitat on epifaunal community structure are mediated by environmental factors that typically co-vary in marine habitats: structural complexity and predation risk. Intellectual merit. Studies in terrestrial and marine systems collectively show that the effects of patchiness depend largely on landscape context, i.e., the characteristics and settings of individual landscapes. Progress in exploring what aspects of landscape context modify effects of habitat fragmentation on ecological processes has been slow. The experiments developed for this research directly address primary questions about the role of habitat structure in moderating ecological processes in a critical nursery habitat, and take initial steps forward to explore three important concepts: (i) how communities respond to the process of habitat fragmentation, rather than simply how communities differ between continuous and patchy areas; (ii) the relative influences of the two major components of habitat fragmentation (habitat loss and increasing patchiness) on biodiversity; and (iii) how co-varying factors in naturally occurring habitats alter faunal responses to large-scale alteration of habitat. Broader impacts. Seagrasses provide critical ecosystem services including the formation of critical refuge and foraging areas for the postlarvae, juveniles, and adults of many species of fishes and invertebrates that feed on diverse assemblages of invertebrate epifauna and infauna. However, disturbances that fragments seagrass habitat are increasingly common and approximately 30% of the world's seagrass habitat has been lost. Disturbances to seagrass habitat may alter feedbacks between plants and invertebrate grazers that influence ecosystem function and may increase susceptibility to species invasions. In addition to addressing these applied issues, this research includes participation of under-represented groups in the biological sciences. Student assistants for the project are selected from the SDSU Bridges to the Baccalaureate Program. The investigator has developed outreach activities for K - 12 students through San Diego's Ocean Discovery Institute.