Publication Date

Fall 2015

Degree Type


Degree Name

Master of Science (MS)


Moss Landing Marine Laboratories


Michael Graham


Barnacle, Limpet, Pelvetiopsis limitata, Rock type, Rocky intertidal, Species interactions

Subject Areas

Ecology; Marine geology


The barnacle assemblage in the high rocky intertidal zone has provided an excellent study system to examine species interaction webs. This assemblage consists of a small set of species: barnacles, a variety of macroalgae, and a suite of limpet grazers. Despite the extensive intertidal research occurring along the central California coast, little is known about this specific interaction web and what physical factors may influence it in this region. This study examines the direct, indirect, positive, and negative interactions between the intertidal barnacle Balanus glandula Darwin, the brown seaweed Pelvetiopsis limitata Gardner, and limpet grazers, and how the underlying rock type may affect this interaction web at two sites in central California. Results illustrate a significant, positive effect of B. glandula on macroalgal colonization at one site, while limpet grazers appear to be partially driving successful P. limitata recruitment at the other site. Targeted species also appear to be utilizing the substrate at each site differently, suggesting that variation in small-scale complexity and heterogeneity of the underlying rock type plays a role in shaping this interaction web.