Temporal dynamics of gastropod fauna on subtidal sandy sediments of the Ensenada de Baiona (NW Iberian Peninsula)

Abstract

The temporal variation of the gastropod fauna inhabiting sandy sediments of the Ensenada de Baiona (Galicia, Spain) was studied at three subtidal sites from February 1996 to February 1997 by means of quantitative sampling. A total of 5,463 individuals representing 51 gastropod species and 22 families were found. The family Pyramidellidae was the most diverse in number of species (11 species), followed by Rissoidae and Trochidae (4 species each). The dogwhelk, Nassarius reticulatus, and the rissoid snail, Rissoa parva, were the numerically dominant species at the three studied sites; those and other abundant species showed their greatest densities by the end of summer and the beginning of autumn. In general, univariate measures of the assemblage (number of species, abundance, diversity and evenness) showed variations through time; greater values were recorded between summer and autumn depending on the site. Multivariate analyses done on abundance data showed certain seasonality in the evolution of the assemblage as expected for shallow subtidal sandy sediments at temperate latitudes; those seasonal changes were mostly related to variations in abundance of numerically dominant species. Although the measured sedimentary variables did not show significant correlations with faunal univariate parameters, sediment heterogeneity due to the presence of mats of Zostera marina L. and shells of dead bivalves might explain the differences in composition of the gastropod assemblage among sampling sites.

Macroinfauna Dynamics and Sediment Parameters of a Subtropical Estuarine Lake—Coombabah Lake (Southern Moreton Bay, Australia)

“…The temporal variations observed within Coombabah Lake, however, are in contrast to those recorded in some other studies within Australian intertidal systems that reported no significant seasonal trends (Dittman, 2002;Jones, Watson-Russell, and Murray, 1986;Rainer, 1981). In many cases, intra-annual trends in macrofauna dynamics are attributable to patterns of species recruitment, water column and sediment conditions, competition, and predation stresses (Moreira, Aldea, and Troncoso, 2010). These facts could help explain the lower Predation is most often presumed to be an important organising force of soft-sediment community structures (Bell, 1980;Brey, 1991).…”

“…Consequently, estuarine sediments often support high abundances and biomasses of benthic macrofauna (Moreira, Aldea, and Troncoso, 2010;Snelgrove, 1999), which provide vital food for many crustacean, fish, and shorebird species (Wolff, 1987;Ysebaert et al, 2005). As a result, intertidal habitats are of high conservation value (Fujii, 2007;Kennish, 2002) and often function as nursery grounds for important recreational and commercial fish species (Gray, McElligott, and Chick, 1996;Ysebaert et al, 2005).…”

Seasonality and trophic diversity in molluscan assemblages from the Bay of Tunis (southern Mediterranean Sea)

“…In this case, most of these changes were related to few dominant species that were abundant only in some periods, such as M. subpictus and the non-indigenous P. emertoni in winter, which are associated with vegetated habitats, or to the strong reduction of the species richness in summer. A maximum of abundance and species richness values have been found in colder regions at the end of the summer and in autumn (Ibañez & Dauvin, 1988;Gestoso et al, 2007;Moreira et al, 2010), as a result of recruitment events occurring in spring and summer. In the Mediterranean, maxima are observed usually in spring and summer (Koulouri et al, 2006;Rueda et al, 2001;Sardà et al, 1999), in agreement with our own observations at La Goulette.…”

The community structure of Prosobranchia (Mollusca: Gastropoda) on shallow soft bottoms of the Çanakkale Strait

“…In the present study, we recorded a 0.47% dominance value of J. striatus. Recently, Moreira et al, (2010) reported 4 species of Rissoidae and Trochidae in subtidal sandy sediments of Iberian Peninsula. In this study, we recorded 5 species from Trochidae and 4 species from Rissoidae.…”