Rock boring by the bivalve Petricola dactylus increases invertebrate richness in a wave-swept Patagonian intertidal environment

MARIA BAGUR; GABRIELA PALOMO; JORGE L. GUTIÉRREZ; LORENA ARRIBAS

Aberdeen

Conferencia; 2nd. World Conference on Marine Biodiversity; 2011

University of St Andrew y University of Aberdeen

Boring invertebrates increase bedrock topographical complexity and overall habitat diversity. Intertidal Petricola dactylus burrows persist after bivalve death, infill with sediments, and provide habitat to other species in otherwise flat limestone surfaces that are subject to intense wave splash. Here, we analyzed if vacant burrows of the bivalve P. dactylus increase invertebrate richness in a Patagonian intertidal limestone outcrop. Areas with and without burrows were compared by constructing species accumulation curves (n = 48). Rarefaction techniques and the Chao 2 species richness estimator were used to analyze the curves. Species richness was higher in areas with burrows (17 ± 1.33) than unmodified areas (6 ± 1.4). Chao 2 values did not differ from the observed species richness values, indicating that our sampling was exhaustive enough to detect all the species in each habitat type. Eleven out of the 17 species found were restricted to burrows, 2 species were exclusively found at the rock surface, and only 4 species were found at both habitats. The most common species inhabiting burrows were the mussel Brachidontes rodriguezii and the polychaetes Lumbrineris tetraura and Syllis gracilis. This results show that vacant P. dactylus burrows dramatically increase invertebrate richness in physically stressful intertidal limestone outcrops.