The ecology of sandy beaches in southern Africa

Structure of molluscan assemblages in sheltered intertidal unconsolidated environments

“…The most abundant species in the channel were those that were locally abundant (B. striata, S. proficua and C. orbiculata) or that occurred in five or more sectors in relatively high densities (C. atratum, O. minuta, A. brasiliana, Tagelus divisus, T. plebeius and T. lineata). Gastropods were well represented in this area (32% of the species) compared to other studies in sandy beaches (McLachlan et al, 1981;Dexter, 1983;Bally, 1983;Rafaelli et al, 1991;Defeo et al, 1992;Souza and Gianuca, 1995). Most (75%) of the gastropods occurred exclusively in the substrates with sand and rock fragments, which supported both soft and hard bottom species.…”

“…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.…”

Descrição do ciclo reprodutivo de Donax hanleyanus (Bivalvia, Donacidae) no sul do Brasil

“…Segundo CARDOSO & VELOSO (2003), sua distribuição se estende de 17ºS (região tropical) até 37ºS (região temperada). A diversidade e a ampla distribuição do gênero Donax Linné, 1758 (MORRISON, 1971;ANSELL, 1983;SICARDI, 1993), as grandes flutuações na densidade populacional (COE, 1956;PENCHASZADEH & OLIVIER, 1975;DEFEO & ALAVA, 1995) e a importância ecológica desses animais (MCLACHLAN & HANEKON, 1979;MCLACHLAN et al, 1981;CARDOSO & VELOSO, 2003), associadas à sua importância econômica (MCLACHLAN et al, 1996), têm gerado uma série de investigações sobre a ecologia e a biologia desses moluscos.…”

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

“…Molluscs are second in abundance to polychaetes, while crustaceans are least and also have the fewest species. Although crustaceans may be proportionally more abundant in sandy beaches subjected to strong, frequent wave action (Dexter, 1983(Dexter, , 1984McLachlan et al, 1993), their species richness is still generally low (up to 16 species) (McLachlan et al, 1981;Dexter, 1984;McLachlan, 1990;Defeo et al, 1992;Jaramillo et al, 1993;McLachlan, 1996). Studies in sheltered environments are rare and generally conducted in estuaries, where salinity varies widely and where input of sediment and nutrients is constant.…”