Marine Landscape Ecology Lab

Department of Marine Science

Landscape Based Mechanisms of Boundary Formation in Rocky Intertidal Communities

As part of a long term collaboration in British Columbia, Canada with the Center For Environmental Analysis at California State University, Los Angeles and the California Institute of Technology our lab is investigating the interaction between landscape driven physical and biological processes that drive boundary formation in the mussel Mytilus californianus, a prominent member of rocky intertidal communities in the Pacific Northwest.

Classic ecological theory views the distributional limit of M. californianus as an equilibrium process whereby the predatory sea star Pisaster ochraceus maintains the lower distributional boundary of the mussel in the intertidal by foraging on mussels that fall within the upper limits of the sea stars foraging range. Our experimental studies suggest that this interaction may be a nonequlibrium process that is in part related to the interaction between the physical landscape, physical forcing factors and the ability of Pisaster to forage in different physical environments. This work will be expanded to include studies of how the interactions between physical and biological processes help shape the three dimensional structure of intertidal communities. This work will help to further quantify the biological and physical mechanisms that drive boundary formation in marine species that inhabit coastal communities.

The lower distributional limit of Mytilus californianus before (left photograph) and one year after (right photograph) an experimentally induced increase in the abundance of Pisaster ochraceus.
The lower distributional limit of Mytilus californianus before (left photograph) and one year after (right photograph) an experimentally induced increase in the abundance of Pisaster ochraceus. After one year the lower boundary of the mussel bed has demonstrated a significant upward recession.