Summary PROJECT INACTIVE

As part of a collaboration with California State University, Los Angeles and the University of California at Los Angeles our lab group is participating in a project to enhance our understanding of how disturbance structures natural communities. Our understanding of how physical disturbance shapes the structure of populations and communities owes much to field studies of wave-generated gap formation in mussel beds. Prior studies depict mussel beds as a non-equilibrium system, in which disturbance is spatially unpredictable, generating a random patchwork of mussel cover and gaps. The study tests assumptions and predictions of an alternative view, that disturbance shows predictable landscape patterns that depend not merely on spatial distribution of external forcing (wave stress) but also on biological processes determining the structure of the aggregation. Specifically, spatially varying mussel productivity (recruitment and growth), physiological stress, and predation interact to produce landscape patterns in the structure of the mussel cover. Field work emphasizes construction of a detailed GIS database using geospatial sampling methods applied to mussel bed sites in Barkley Sound, British Columbia. GIS data layers for each site include wave force, topography (tidal height, slope, and aspect), mussel size structure, mussel bed thickness, differentiation of layering, and size-specific attachment strengths stratified by layer. GIS interpolations and regression analyses are used to first examine assumptions of the hypothetical landscape process and then test specific predictions regarding spatial patterns in the occurrence of disturbance and recovery.

Student Involvement

Two graduate students, Daniel Orr, Mary Young have participated in this project. Mr. Orr and Ms. Young have both completed their graduate degrees. Four CSUMB undergraduates have been supported by the project; Amber Reichert, Patrick Sabordo, Veronica Larwood and Franco Sanchez. Ms Reichert is now a graduate student at Moss Landing Marine Labs, Mr. Sabordo works for CDFW while Ms. Larwood has been hired as a full time research position within this project. Mr Sanchez begin worke within the project this summer.

Broader Significance

The proposed work would test assumptions and predictions of an alternative view that disturbance shows predictable landscape patterns that depend not merely on spatial distribution of external forcing (wave stress) but also on biological processes determining the structure of the aggregation. Therefore, spatial patterns of gap formation and recovery in nature may in fact emerge from a unified landscape process.