Composition, structure and zonation of intertidal macroinfauna in relation to physical factors in microtidal sandy beaches in Rio de Janeiro state, Brazil

• Published in: Scientia marina 2003-12, Vol.67 (4), p.393-402
• Main Authors: Veloso, V G, Caetano, CHS, Cardoso, R S
• Format: Article
• Language: English
• Subjects: Donax haleyanus; Emerita brasiliensis; Excirolana braziliensis; Hemipodus oliveri; Marine; Phaleria testacea; Pseudorchestoidea brasiliensis
• ISSN: 0214-8358
• DOI: 10.3989/scimar.2003.67n4393

The intertidal macroinfauna of fiftheen exposed sandy beaches located in Rio de Janeiro State was studied to determine species richness, density, biomass and zonation. Morphodynamic influence on biological parameters is also evaluated in this paper. Dean's morphodynamic index (W) ranged from reflective to intermediate values and mean grain size ranged from fine to coarse sands. A total of 17 species were identified, with the crustaceans Emerita brasiliensis, Excirolana braziliensis and Pseudorchestoidea brasiliensis being the most abundant species. Species richness had a significant positive linear relationship with W values, swash period and slope, and a negative relationship with grain size. Significant positive relationships were also observed for total density with the swash period and slope, total biomass with slope, density of Emerita brasiliensis with swash period and slope and biomass of Emerita brasiliensis with slope. Zonation analysis showed that two or three biological zones could be recognised, with the two-zone pattern being observed in most of the beaches. This pattern consisted of a lower zone characterised by Emerita brasiliensis, Donax haleyanus and Hemipodus oliveri; and an upper zone characterised by Excirolana braziliensis, Pseudorchestoidea brasiliensis and Phaleria testacea. The three-zone pattern as a disruption of the general two-zone pattern and its formation was attributable to the variation in the distributions of P. brasilensis and E. braziliensis. Our results suggest that beach morphodynamics is the best predictor for the variability of macroinfaunal community composition.Original Abstract: Composicion, estructura y zonacion de la macroinfauna intermareal en relacion a factores fisicos en playas arenosas micromareales en el estado de Rio de Janeiro, Brasil. - La macroinfauna intermareal de quince playas arenosas en el Estado de Rio de Janeiro fue estudiada con el objetivo de determinarse la riqueza de especies, la densidad, la biomasa y la zonacion. La influencia de la morfodinamica en los parametros biologicos tambien fue evaluada en este trabajo. el indice morfodinamico de Dean (W) fluctuo de reflectivo a valores intermediarios y el tamano medio de los granos oscilo entre arenas finas a gruesas. Un total de 17 especies fueron identificadas, siendo los crustaceos Emerita brasiliensis, Excirolana braziliensis y Pseudorchestoidea brasiliensis las especies mas abundantes. La riqueza de especies tuvo correlaciones lineales positi