Composition and distribution of benthic molluscs on intertidal flats of Paranaguá Bay (Paraná, Brazil)

Abstract

SUMMARY: Mollusc species composition, abundance and spatial distribution were analysed from April 1996 to October 1997 on two tidal flats in Paranaguá Bay (SE Brazil) at the entrance (St. I) (Lat. 25º32'S) and in the intermediate sector (St. II) (Lat. 25º30'S) of the estuary. At St. I, with the highest and least variable salinity, species richness (R = 40) and diversity (H´ = 1; D S = 0.85) were higher than at St. II (R = 22 and H´ = 0.54; D S = 0.57). The tropical clam Anomalocardia brasiliana was the most conspicuous mollusc of the two assemblages, followed by Cerithium atratum, Neritina virginea and Crassostrea sp. at St. I and by Macoma constricta and N. virginea at St. II. On the two flats, the decrease in species richness and abundance towards the upper tidal levels suggests a strong relationship between relative tolerance to physiological stress in the organisms and the degree of immersion/submersion.Key words: Benthic molluscs, species composition, spatial distribution, tidal flats, Anomalocardia brasiliana, Paranaguá Bay, southeastern Brazil. RESUMEN: COMPOSICIÓN Y DISTRIBUCIÓN DE MOLUSCOS BENTÓNICOS EN LLANOS INTERMAREALES DELA BAHÍA DE PARAGUA-NÁ (PARANÁ, BRASIL). -Se ha analizado la composición específica de moluscos, abundancia y distribución espacial en dos llanos intermareales de la bahía de Paraguaná (SE de Brasil), entre abril de 1996 y octubre de 1997, en la boca (estación I) (Lat. 25º32'S) y en el sector intermedio (estación II) (Lat. 25º30' S) del estuario. En la estación I, con la salinidad más elevada y menos variable, la riqueza específica (R = 40) y diversidad (H' = 1; D s = 0.85) fueron superiores a los valores detectados en la estación II (R = 22 y H' = 0.54; D s = 0.57). El bivalvo tropical Anomalocardia brasiliana fue el molusco más conspícuo de las dos zonas, seguido por Cerithium atratum, Neritina virginea y Crassostrea sp. en la estación I y por Macoma constricta y N. virginea en la estación II. En los dos llanos, el descenso en riqueza específica y en abundancia hacia los niveles mareales superiores sugiere una fuerte relación entre la tolerancia relativa al estrés fisiológico en los organismos y en el grado de inmersión/emersión.Palabras clave: moluscos bentónicos, composición específica, distribución espacial, llanos intermareales, Anomalocardia brasiliana, Bahía de Paraguaná, Brasil.

Evaluation of the use of Olivella minuta (Gastropoda, Olividae) and Hastula cinerea (Gastropoda, Terebridae) as TBT sentinels for sandy coastal habitats

“…Therefore, although this gastropod can also inhabit estuarine sandy beaches (Petracco, personal observation), its occurrence seems to be more restricted than O. minuta. In fact, besides the frequent occurrence in sheltered, and in reflective and dissipative exposed sandy beaches (Denadai et al 2005;Petracco et al 2014;Rocha-Barreira et al 2005), O. minuta is also frequently recorded in tidal flats and estuaries (e.g., Boehs et al 2004;Rolemberg et al 2008).…”

Spatial variation of intertidal macroinvertebrates and environmental variables in Robbins Passage wetlands, NW Tasmania

“…A similar pattern was found by (Dankers & Beukema, 1981) in the Wadden Sea, but Edgar and Barrett (2002) found that in Tasmanian estuaries the number of species and abundance continued to increase as they moved down shore to 0.7 m below low water mark. Honkoop et al (2006) found greater numbers of individuals and species at lower tidal levels in northwestern Australia, and Boehs et al (2004) found that molluscs decreased in abundance and diversity at higher tidal levels, i.e. between mid-and high tide.…”

“…Many studies have investigated the distribution (Chainho et al, 2006;Rodrigues et al, 2006), abundance Dittman, 2002b), diversity (Boehs et al, 2004) and biomass (Masero et al, 1999;Silva et al, 2006) of invertebrates on intertidal flats. There have also been many studies that examine the effect of environmental variables on invertebrate abundance and community composition (Anderson, 1972;Castel et al, 1989;Edgar & Barrett, 2002).…”

Distribuição espaço-temporal de Olivella minuta (LINK, 1807) (Mollusca, Gastropoda, Olividae) na praia de Barequeçaba, Litoral Norte do Estado de São Paulo

“…(Rios, 1994). É uma das espécies de molu sco mais frequentes nas praias abrigadas do Canal de São Sebastião, litoral norte do Estado de São Paulo (Denadai et al 2005), e uma das espécies mais abundantes na praia de Barequeçaba (Shimizu, 1991) (Severeyn et al 2003;Boehs et al 2004), a sua distribuição espacial (Shimizu, 1991;Viana et al 2005;) a 9 mm 1m 1,5m…”

“…No entanto, a exemplo de Barequeçaba, a maioria dos estudos da macrofauna de praias arenosas são desenvolvidos com espécies exclusivas da porção emersa da praia, do pós-praia ou migradores mareais (ver Severeyn et al 2003;Arruda e Amaral, 2003;Boehs et al 2004;Denadai et al 2005;Camargo, 2012 Possui aproximadamente 1200 metros de extensão, delimitada por dois costões rochosos, perfil suave (~0,78°) e sedimento composto por areia fina e muito fina, com baixo conteúdo de matéria orgânica (~0,75%) (Nucci et al 2001;Denadai et al 2005, Tominaga et al 2006. Barequeçaba recebe constantemente descargas de água doce, provenientes de um riacho permanente localizado na porção Leste da praia e de um número variado de pequenos cursos da água temporários (Shimizu, 1991).…”