Differences in composition of shallow-water marine benthic communities associated with two ophiolitic rock substrata

The influence of the rock mineralogy on population density ofChthamalus(Crustacea: Cirripedia) in the Ligurian Sea (NW Mediterranean Sea)

“…In investigated localities of the Ligurian coast, barnacle densities were maximal in the upper splash zones characterised by substrates particularly rich in calcite, with poor levels of silicates and the absence of quartz. This mineral seemed to inhibit the development of the populations, as already documented for other species and habitats in the Mediterranean Sea (Bavestrello et al 2000(Bavestrello et al , 2003(Bavestrello et al , 2018Guidetti et al 2004;Cattaneo-Vietti et al 2004). The presence of quartz has been considered one of the most important factors in driving larval settling and ultimate species composition on hard substrata.…”

“…appear good models to assess the role of substrata mineral composition in determining settlement and recruitment of sessile invertebrates. Moreover, Bavestrello et al (2018) have observed that the density of C. stellatus was very different on two neighbouring ophiolitic outcrops dip into the sea under similar environmental conditions but showing different silica concentrations.…”

“…Among the main abiotic factors, that can favour or inhibit species settlement, the mineralogy of the substrate has been only sporadically considered. On the other hand, it has been observed that free larvae of sessile organisms show an unsuspected ability to recognize and select different rocky substrates, with important repercussions on the community structure (Cerrano et al 1999;Bavestrello et al 2000Bavestrello et al , 2018Cattaneo-Vietti et al 2002;Guidetti et al 2004;Calcinai et al 2008).…”

Lack of general associations between intertidal assemblages and rock hardness

“…McGuinness & Underwood 1986;Cattaneo-Vietti et al 2002;Malm et al 2003). For taxon richness, rock-related differences have been identified intertidally for invertebrates (Bessey et al 2018) and from intertidal and subtidal reefs for algae (Cattaneo-Vietti et al 2002;Guidetti et al 2004;Bavestrello et al 2018). Differences in assemblage structure among rock types have been identified for mixed algal and invertebrate (Bessey et al 2018) and mollusc (Liversage & Benkendorff 2013;Liversage et al 2014) assemblages intertidally, and for algal and grazer (Davidson & Chadderton 1994) and epibenthic and fish (Guidetti et al 2004) assemblages subtidally.…”

“…Field-based observational studies and experimental manipulations have variously identified differences in the abundances of individual taxa (e.g. Moore & Kitching 1939;McGuinness & Underwood 1986;Raimondi 1988), taxon richness (Cattaneo-Vietti et al 2002;Bavestrello et al 2018;Janetzki et al 2018) and assemblage composition (e.g. Davidson & Chadderton 1994;Guidetti et al 2004;Bessey et al 2018) from comparisons among different rock types.…”