A highly diverse molluscan assemblage associated with eelgrass beds (<i>Zostera marina</i> L.) in the Alboran Sea: Micro-habitat preference, feeding guilds and biogeographical distribution

Abstract

summaRY: The fauna of molluscs associated with deep subtidal Zostera marina beds (12-16 m) in southern spain (alboran sea) has been characterised in terms of micro-habitat preference, feeding guilds and biogeographical affinity. The species list (162 taxa) is based on sampling completed before the strong eelgrass decline experienced in 2005-2006, using different methods (small agassiz trawl covering 222 m 2 and quadrates covering 0.06 m 2 ) and different temporal scales (months, day/night). dominant epifaunal species are Jujubinus striatus, Rissoa spp. and Smaragdia viridis in the leaf stratum and Nassarius pygmaeus, Bittium reticulatum and Calliostoma planatum on the sediment. nevertheless, the infauna dominated the epifauna in terms of number of individuals, including mainly bivalves (Tellina distorta, T. fabula, Dosinia lupinus). The epifauna of both the sediment and leaf strata included high numbers of species, probably due to the soft transition between vegetated and unvegetated areas. The dominant feeding guilds were deposit feeders, filter feeders and peryphiton grazers, but ectoparasites (eulimids), seagrass grazers (Smaragdia viridis) and an egg feeder (Mitrella minor) also occurred, unlike in other eelgrass beds of europe. The molluscan fauna of these Z. marina beds is essentially derived from the local fauna, which includes many widely distributed species along european coasts, with a low representation of strictly mediterranean or strictly atlantic species. This fauna is richer than that found in other eelgrass beds of europe, and deserves important attention for conservation.Keywords: bivalves, gastropods, seagrass, biodiversity, alboran sea, biogeographical distribution.Resumen: Una comunidad altamente diversa de moluscos asociados a praderas de Zostera marina del mar de Alborán: preferencias de micro-hábitat, grupos tróficos y distribución biogeográfica. -La fauna de moluscos asociada a praderas infralitorales profundas de Zostera marina (12-16 m) del sur de españa (mar de alborán) ha sido caracterizada en relación a su micro-hábitat preferente, grupo trófico y distribución biogeográfica. el listado faunístico (162 especies) se obtuvo antes de la fuerte regresión sufrida entre los años 2005 y 2006, usando diferentes métodos (pequeño patín de agassiz que muestreaba 222 m 2 y cuadrantes que muestreaban 0.06 m 2 ) y escalas temporales (meses, día/noche). Las especies dominantes asociadas al estrato foliar son Jujubinus striatus, Rissoa spp. y Smaragdia viridis y al sedimento son Nassarius pygmaeus, Calliostoma planatum y Bittium reticulatum, entre otras. no obstante, la endofauna domina a la epifauna, incluyendo principalmente bivalvos como Tellina distorta, T. fabula y Dosinia lupinus. La epifauna asociada al sedimento y al estrato foliar tiene una gran riqueza de especies, probablemente debido a la suave transición entre zonas cubiertas y no cubiertas. Los grupos tróficos dominantes fueron los depositívoros, filtradores o ramoneadores, pero ectoparásitos (eulímidos) y consumidores de fanerógamas ma...

Composition and structure of the molluscan assemblage associated with a Cymodocea nodosa bed in south-eastern Spain: seasonal and diel variation

“…In these beds, predators represent another important group indicating high prey availability as it was reported for Z. marina beds of the Alboran Sea Rueda et al 2009a). The presence of the egg feeder Mitrella minor may point out the importance of this habitat as a spawning and nursery site for different species as found in Z. marina beds (Arroyo et al 2006, Rueda et al 2009a. The presence of seagrass feeders such as Smaragdia viridis is also of interest as in this way seagrass carbon might be allocated to higher trophic levels such as fish (Rueda and Salas 2007).…”

“…The dominant feeding guild in the C. nodosa bed of Genoveses was represented by microalgal grazers associated with the leaf stratum as it was also found for the epifauna associated with C. nodosa in Italy (Terlizzi and Russo 1997;Chemello et al 1997) or with Z. marina (Mattila et al 1999;Nakaoka et al 2001;Rueda et al 2009a). In these beds, predators represent another important group indicating high prey availability as it was reported for Z. marina beds of the Alboran Sea Rueda et al 2009a).…”

“…Only 5 species (Pusillina marginata, Gibbula ardens, Rissoa similis, Bittium latreilii and Jujubinus striatus) occurring in the C. nodosa bed of Genoveses were also reported by Chemello et al (1997). Eight of the ten most dominant molluscs of the C. nodosa bed of Genoveses belong to the group of epifaunal species associated with vegetated bottoms; out of these, Smaragdia viridis and Rissoa membranacea are strictly associated with seagrasses (Rueda and Salas 2007;Rueda et al 2009a), and other species such as Rissoa monodonta, Jujubinus striatus, Gibbula leucophaea and Tricolia tenuis are generally found in macroalgae or seagrass beds in southern Spain (Rueda and Salas 2003;Rueda et al 2009a).…”

“…The species were also characterized in terms of their preference for different microhabitats within the C. nodosa bed, their feeding guilds and their biogeographical distribution, following similar categories as used by Rueda et al (2009a) for molluscan assemblages associated with eelgrass beds in the Alboran Sea (Table 1).…”

“…Information on microhabitat preference and feeding guilds has been obtained from the literature on the molluscan fauna associated with seagrass beds (Ledoyer 1962(Ledoyer , 1966Templado 1982;Hergueta 1996;Luque and Templado 2004;Quintas 2005;Rueda and Salas 2007) or from the general literature on molluscs ecology (Fretter and Graham 1962;Tebble 1966;Morton 1967;Graham 1971;Bouchet et al 1979;Nordsieck and García-Talavera 1979;Kohn 1983;Russell-Hunter 1983;Luque 1984Luque , 1986Templado et al 1993;Hayward and Ryland 1995;Salas 1996: Gómez-Rodríguez andPérez-Sánchez 1997;Beesley et al 1998;Rueda et al 2009a). Additional information on the preference of species for different microhabitats within C. nodosa beds and feeding habits has been obtained during the present sampling and by laboratory observations.…”