California Sea Grant College Program

The extensive anthropogenic armoring of the shoreline in California changes the substrate available to settling invertebrate larvae and algal spores that are passively distributed in the ocean currents. Rock types available to settlers likely influences community structure in the intertidal, as rock characteristics have been shown to favor or inhibit settlement. Much research has been done examining the mechanisms that determine intertidal community patterns, but the role of rock type has been largely neglected. My goals are to: 1) determine the structure of community assemblages occurring on different rock types, 2) examine the mechanisms responsible for any differences, and 3) link the community structure patterns to life history characteristics of selected species. I have conducted two studies—the first comparing two sites with armored, rip-rapped shorelines (Chapter 2) and the second using settlement plates at two sites with different bedrock within Monterey Bay, California (Chapters 3 and 4). The intertidal community structure on the armored rocks and settling plates shows different patterns for certain species distributions that warrant further examination. These studies will help in predicting how continued armoring of the shoreline will affect species assemblages, as well as enhancing our understanding of variation in intertidal community assemblages at different sites along the coast.