Abstract

CERDA, MAURICIO  and  CASTILLA, JUAN CARLOS. Diversity and biomass of macro-invertebrates in intertidal matrices of the tunicate Pyura praeputialis (Heller, 1878) in the Bay of Antofagasta, Chile. Rev. chil. hist. nat. [online]. 2001, vol.74, n.4, pp. 841-853. ISSN 0716-078X.  doi: 10.4067/S0716-078X2001000400011.

The study was conducted to analyze the biological diversity and biomass of macro-invertebrates in intertidal matrices of Pyura praeputialis (Heller, 1878) in the Bahía de Antofagasta, where the species is confined along approximately 70 km of coastline. Three sites were studied inside the Bay: one located approximately at the center P. praeputialis geographical distribution in the bay and two around the north and south limits respectively (ecotones). The crevices and interstices between individuals in the dense matrices of P. praeputialis provide bio-habitat, such as those described for ecosystem-engineer species. A total of 96 taxa of macro-invertebrates (gama diversity), corresponding to nine phyla, associated to P. praeputialis matrices were recorded. The richer taxa were: gastropod (28 %), polychaeta (26 %), decapod (15 %) and bivalve (14 %). The mean biomass of invertebrate registered was of 246,40 g m^-2. The paper discusses the elevated diversity of macro-invertebrates recorded in the Antofagasta´s P. praeputialis matrices, the observed patterns along the geographical distribution inside the bay and the role of this tunicate as a bio-engineer species. The results are compared with a similar study on P. stolonifera carried out in Natal, South Africa and with respect to the diversity of macro-invertebrate associated to other bio-engineer species

Keywords : tunicate; Pyura praeputialis; rocky intertidal; macro-invertebrate; diversity; bio-engineer; Antofagasta; Chile.