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

BAGUR, MARIA; GUTIÉRREZ, JORGE LUIS CEFERINO; PALOMO, MARIA GABRIELA; ARRIBAS, LORENA PILAR

Aberdeen

Congreso; World Conference on Marine Biodiversity; 2011

Boring invertebrates increase bedrock topographical complexity and overallhabitat diversity. Intertidal Petricola dactylus burrows persist after bivalve death,infill with sediments, and provide habitat to other species in otherwise flatlimestone surfaces that are subject to intense wave splash. Here, we analyzed ifvacant burrows of the bivalve P. dactylus increase invertebrate richness in aPatagonian intertidal limestone outcrop. Areas with and without burrows werecompared by constructing species accumulation curves (n = 48). Rarefactiontechniques and the Chao 2 species richness estimator were used to analyze thecurves. Species richness was higher in areas with burrows (17 ± 1.33) thanunmodified areas (6 ± 1.4). Chao 2 values did not differ from the observed speciesrichness values, indicating that our sampling was exhaustive enough to detect allthe species in each habitat type. Eleven out of the 17 species found wererestricted to burrows, 2 species were exclusively found at the rock surface, andonly 4 species were found at both habitats. The most common species inhabitingburrows were the mussel Brachidontes rodriguezii and the polychaetesLumbrineris tetraura and Syllis gracilis. This results show that vacant P. dactylusburrows dramatically increase invertebrate richness in physically stressfulintertidal limestone outcrops.