Meeting Abstract
7.9 Jan. 4 Does geologic history matter? The effects of substratum on rocky intertidal communities. PEROTTI, Elizabeth A*; LINDBERG, David R; University of California, Berkeley; University of California, Berkeley marinelizard@berkeley.edu
Rocky intertidal communities, which have been hotbeds for conceptual advances in community ecology, exist in a mosaic of rock substrates. Nowhere else in the world is this mosaic more pronounced than along the western edge of North America because of the geologic origins and tectonics of this region. The organisms living on these substrates have their own histories as well and have been interacting on various substrates with other organisms for different amounts of time. The Marin Headlands possesses abundant rock units of disparate origins in close proximity, providing a unique opportunity to directly test substrate effects on intertidal ecology. This study begins to 1) evaluate the relative importance of an important rock property-surface roughness-on local diversity and community structure in the rocky intertidal, 2) test how substrate type influences succession, structure, and diversity of communities of intertidal organisms, and 3) identify species-specific or clade-specific responses to substratum and substrate properties. Experimental plots in each of three adjacent rock types (i.e. chert, basalt, sandstone) included replicated control and cleared rock plots as well as three ferroconcrete plates of different roughness. Results suggest that surface roughness may not be the primary substrate property structuring intertidal communities. However, roughness seems to be important for some organisms such as certain barnacles and algae. Species composition and diversity also differ between sandstone and other rocks. Natural substrates supported different communities than artificial substrates. Resource managers and conservation biologists will be able to use information acquired through this study to implement more effective initiatives designed to protect these natural resources and evaluate the recovery of disturbed communities.
