Reducing the data-deficiency of threatened European habitats: Spatial variation of sabellariid worm reefs and associated fauna in the Sicily Channel, Mediterranean Sea

Abstract

a b s t r a c tBiogenic reefs, such as those produced by tube-dwelling polychaetes of the genus Sabellaria, are valuable marine habitats which are a focus of protection according to European legislation. The achievement of this goal is potentially hindered by the lack of essential empirical data, especially in the Mediterranean Sea. This study addresses some of the current knowledge gaps by quantifying and comparing multi-scale patterns of abundance and distribution of two habitat-forming species (Sabellaria alveolata and S. spinulosa) and their associated fauna along 190 km of coast on the Italian side of the Sicily Channel. While the abundance of the two sabellariids and the total number of associated taxa did not differ at any of the examined scales (from tens of centimetres to tens-100 of kilometres), the structure (composition in terms of both the identity and the relative abundance of constituting taxa) of the associated fauna and the abundance of several taxa (the polychaetes Eulalia ornata, Syllis pulvinata, S. garciai, Nereis splendida and Arabella iricolor, and the amphipods Apolochus neapolitanus, Tethylembos viguieri and Caprella acanthifera) varied among locations established~50e100 km apart. Syllis pulvinata also showed significant variation between sites (hundreds of metres apart), analogously to the other syllid polychaetes S. armillaris and S. gracilis, the nereidid polychaete Nereis rava, and the amphipod Gammaropsis ulrici. The largest variance of S. spinulosa, of the structure of the whole associated fauna and of 56% of taxa analysed individually occurred at the scale of replicates (metres apart), while that of the dominant bio-constructor S. alveolata and of 25% of taxa occurred at the scale of sites. The remaining 19% and the total richness of taxa showed the largest variance at the scale of locations. Present findings contribute to meet a crucial requirement of any future effective protection strategy, i.e., identifying relevant scales of variation to be included in protection schemes aiming at preserving representative samples not only of target habitats and organisms, but also of the processes driving such variability.

Sabellaria alveolata sandcastle worm from the Mediterranean Sea: new insights on tube architecture and biocement

“…Material from the Sampieri beach (Ragusa) represents a new record for the species in the southeastern coast of Sicily, from where S. alveolata was still unreported, although already known from other Sicilian sites along the Sicily Strait (Bertocci et al, ; Schimmenti et al, ).…”

“…Furthermore, S. alveolata is also widespread in the western Mediterranean Sea. In this basin, it has mostly been reported from Spanish (Porras, Bataller, Murgui, & Torregosa, ) and Italian waters, including the Tyrrhenian Sea (Delbono et al, ; La Porta, La Valle, & Chimenz Gusso, ; Nicoletti et al, ), the Adriatic Sea (La Porta & Nicoletti, ; Lezzi, Cardone, Mikac, & Giangrande, ), and the Sicily Strait (Bertocci et al, ; Schimmenti et al, ).…”

A complex species complex: The controversial role of ecology and biogeography in the evolutionary history of Syllis gracilis Grube, 1840 (Annelida, Syllidae)

“…Only one lineage (LG3) is in strict relationship with Sabellaria reefs in the Strait of Sicily, even if one individual belonging to this lineage has been also recorded in the northern Tyrrhenian Sea. As Sabellaria reefs are known to host several species that are strictly related to this habitat type (Bertocci et al, ), the hypothesis of a Sabellaria ‐related lineage of the S. gracilis complex cannot be excluded. The sole biogeographic boundaries in the Mediterranean Sea, thence, cannot explain the divergence between different lineages of the S. gracilis complex.…”

“…Among the marine localities, individuals from Eraclea Minoa and Donnalucata were collected on reefs built by the ecosystem engineer polychaete Sabellaria alveolata . Recently, these reefs were re‐evaluated as habitat with great ecological value, hosting a variety of organisms, a part of which show a strict association with this habitat type (Bertocci et al, ). In agreement with the peculiarity of Sabellaria reefs, we considered these samples as different from the ones obtained from shallow assemblages dominated by coralline algae.…”

New records of amphipod crustaceans along the Israeli Mediterranean coast, including a rare Mediterranean endemic species, Maera schieckei Karaman & Ruffo, 1971

“…Many habitats often represent a sink for invasive alien species, unknown species (not yet described) or rare species. Those can be the artificial ( Bonifazi et al 2018 ) or biogenic ( Plicanti et al 2016 , Bertocci et al 2017 ) hard substrates, which can significantly influence the faunal composition especially in countries, such as Israel, where sandy and muddy bottoms show a large extension along the coast. In some cases, such scattered habitats create the favourable conditions for settlement and successive establishment, facilitating the dispersal of the species also over long distances.…”