Temporal variation of annelids in the intertidal zone of beaches of the São Sebastião Channel, southern Brazil

Abstract

Monthly collections were made for one year (August 1995 to July 1996) in the intertidal zone of two beaches (Engenho d'Água and São Francisco) located in the São Sebastião Channel, State of São Paulo, Brazil, in order to establish the seasonal fluctuations of the species and the factors determining these fluctuations. On each beach, a 10 m wide sector of varying width was established, from which 15 samples/month were collected with a cylindrical corer (0·01 m2). The salinity of the interstitial water and the temperature of the sediment were measured monthly, while the granulometric parameters and calcium carbonate and organic matter concentrations were recorded seasonally. The temporal distribution of the species was more homogeneous at Engenho d'Água, where the highest diversity and evenness values were also found, although the number of individuals was lower. At São Francisco, the monthly abundance was higher, but the richness, diversity, and evenness values were lower, showing some heterogeneity in the temporal distribution patterns of the species. Most species at Engenho d'Água reached their peak of abundance in summer and autumn. The most abundant and frequent species at Engenho d'Água were Nematonereis hebes, Cirriformia filigera (summer), Scyphoproctus djiboutiensis (spring), Owenia fusiformis and Isolda pulchella (winter). At São Francisco, the capitellids Capitella capitata, Heteromastus filiformis, and Capitomastus minimus, and the tubificid oligochaetes dominated in the summer, and Laeonereis acuta and Scolelepis squamata in the winter. The log-normal distribution of the species was used to group those species that are sensitive to and those that are tolerant of organic enrichment, over the four seasons of the year.

Diversity and distribution of crustaceans from 13 sheltered sandy beaches along São Sebastião Channel, south-eastern Brazil

“…Our results do not agree with the model proposed by McLachlan (1983) (Rizzo & Amaral, 2000) and mollusc (Denadai & Amaral, 1999) assemblages. The in£uence of habitat heterogeneity on crustacean communities was previously shown by Abele (1976) and Hendrickx (1996).…”

“…Polychaetes are most abundant and have more species in areas with low hydrodynamism and ¢ne sand (Dexter, 1983(Dexter, , 1984, sand mixed with rock fragments (Rizzo & Amaral, 2000) and high organic matter content . Molluscs are second in abundance to polychaetes, while crustaceans are least and also have the fewest species.…”

Structure of molluscan assemblages in sheltered intertidal unconsolidated environments

“…In fact, higher numbers of species and densities are associated with the presence of rock fragments mixed with sand in comparison to typical sandy beaches and rocky shores (McQuaid and Dower, 1990;Denadai and Amaral, 1999). Most studies on sandy beach communities are done on exposed areas with very homogeneous sediment constitution (McLachlan, 1990;McLachlan et al, 1981;Defeo et al, 1992;Jaramillo et al, 1993;Souza and Gianuca, 1995), while studies in sheltered heterogeneous environments are less common (McQuaid and Dower, 1990;Brown et al,1991;Rizzo and Amaral, 2000;Amaral et al, 2003). Sheltered marine sandy beaches are uncommon on most of the Brazilian coast, but are abundant on the northern coast of the State of São Paulo, especially along the São Sebastião Channel.…”

“…Sheltered marine sandy beaches are uncommon on most of the Brazilian coast, but are abundant on the northern coast of the State of São Paulo, especially along the São Sebastião Channel. These beaches afford a varied array of environments and, in general, support a rich intertidal fauna (Amaral et al, 1990;Omena and Amaral, 1997;Denadai and Amaral, 1999;Rizzo and Amaral, 2000;Nucci et al, 2001), in which the molluscs are an important component. We describe here the structure of the molluscan macrofauna assemblages in 13 unconsolidated intertidal environments in the São Sebastião Channel and Caraguatatuba Bay.…”

Modelagem para integração de dados sobre macrobentos em Infraestrutura de Dados Espaciais

“…Anelídeos poliquetas é o grupo dominante na região estudada e têm sido amplamente utilizados em programas de monitoramento ambiental, pois a diversidade e abundância relacionadas com os padrões de distribuição podem revelar se um determinado ambiente encontra-se ou não impactado (Pearson e Rosenberg, 1978;Choi e Koh, 1984;Pocklington e Wells, 1992;Rizzo e Amaral, 2000, 2001a. Dependendo dos fatores hidrodinâmicos e da heterogeneidade do substrato, os poliquetas podem dominar tanto em riqueza quanto em número de indivíduos, sendo representados por mais gêneros do que qualquer outro grupo animal (Brown e McLachlan, 1990;Amaral et al, 1995).…”