Recruitment patterns in an intertidal species with low dispersal ability: the reef-building Dendropoma cristatum (Biondi, 1859) (Mollusca: Gastropoda)

Abstract

In the Mediterranean, the gastropod Dendropoma cristatum (sin. D. petraeum (Monterosato, 1884)) is the primary builder of the vermetid reef, an intertidal bioconstruction of exceptional ecological importance. Despite awareness of the need for conservation of this key species, the biology of D. cristatum remains poorly understood. The recruitment of D. cristatum deserves particular attention because the absence of a planktonic larval stage limits its dispersal ability. We examined the temporal pattern of recruitment during the breeding season of D. cristatum from June to September in 2013. Specifically, we compared the two portions of the vermetid reef (i.e. the inner edge and the outer edge) at localities with different exposures to wave motion. The number of recruits peaked in July, when it was significantly higher in the outer than in the inner edge. No differences emerged between localities with different wave exposures; however, the width of the reef was significantly related to the exposure index. Although there are still several gaps in our knowledge of the recruitment dynamics of D. cristatum, this study contributes to characterising recruitment rate variation at small spatial and temporal scales.

Meiofauna associated with vermetid reefs: the role of macroalgae in increasing habitat size and complexity

“…Vermetid reefs can be divided into three morphological zones along a horizontal axis, extending from the shore to the sea: (1) the inner margin, which corresponds to the terrestrial boundary; (2) the ''cuvette zone'', the central area of the reef with shallow pools named cuvettes located between the inner and the outer margins of the reef; and (3) the outer margin, the sea boundary of the reef (Molinier and Picard 1953;Chemello and Silenzi 2011). These zones differ in hydrodynamic features (such as emersion and wave exposures), creating different microhabitats with distinct populations (Chemello and Silenzi 2011;Chemello et al 1998;Sarà et al 2014;Franzitta et al 2016).…”

Abundance of the reef-building Petaloconchus varians (Gastropoda: Vermetidae) on intertidal rocky shores at Ilha Grande Bay, southeastern Brazil

“…The lack of a significant correlation between the wave fetch and the belt width of the P. varians reefs suggests that wave action does not affect the distribution of this species along the intertidal. However, Franzitta et al (2016) found a significant relationship between the width of the Dendropoma cristatum reef and the exposure index in the Mediteranea Sea. The index used in the present study may be less sensitive at a small scale.…”

Settlement performance of the Mediterranean reef-builders Dendropoma cristatum (Biondi 1859) in response to natural bacterial films

“…are scant. Temporal pattern of recruitment for the central Mediterranean D. cristatum has been described by Franzitta et al (2016), which recorded consistent differences during the breeding season and between the inner and the outer reef rims. The authors suggested that physical and environmental conditions that characterize the two rims may affect the settlement success and post-settlement mortality of settlers, being responsible for the observed within-reef differences.…”

“…the mixture of the best biofilm former selected isolates (BF), Total Isolates (TI), 32-day, 23-day, 13-day and 0-day old (a sterilised control with no biofilm), were fastened on the outer edge of the reef (Fig. 2 and Table 1), previously described as the portion of a vermetid reef with the highest settlement success (Franzitta et al, 2016). During field deployment, the blocks were carefully handled by means of sterile gloves and limiting the contact with their sides, aiming to do not contaminate or disturb the biofilm on the top face of the blocks.…”

“…A total of 96 blocks was included and analyzed for settlement of D. cristatum after 5-day exposure to natural conditions (between August the 5th and the 10th 2016, because the higher number of recruits on the outer margin was observed in July and August, Franzitta et al, 2016). After exposure, the whole set of blocks was collected and the number of settled D. cristatum was scored under a microscope.…”