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Saltworks are peculiar artificial ecosystems and holds great interest for basic research. In fact the cooling vat (the first pond of the evaporating series) is a good example of a relatively closed area and can be considered an excellent in the field open-air laboratory, namely a mesocosm reproducing a simplified model of the natural condition of hyperaline lagoons. The aim of the present work was to analyse the structure, composition and distribution of molluscan assemblages and to identify the faunistic relationships between the cooling vat and the neighbouring basin of Stagnone di Marsala, beside considering exchanges between saltwork, Stagnone di Marsala and sea, on soft- bottom, covered by Cymodocea nodosa. In structural terms, two molluscan communities can be identified. As regard the saltwork, the community was always characterized by halolimnobic and euryaline species such as Ventrosia ventrosa, Loripes lacteus, Abra segmentum and Pirenella conica. while the community inhabiting Stagnone was composed mainly of marine taxa; here a good exchange with the sea is confirmed by the high values for species richness and diversity gives rise mainly to the presence of marine taxa: e. g Jujubinus striatus, Dikoleps nitens, Rissoa paradoxa, R. similis, Columbella rustica etc. The saltwork molluscan assemblage doesn’t seem to be similar to that of the Stagnone. The low specific richness, the high abundance and the low evenness, showed a pioneer stage of colonization, being poor in species and dominated by taxa with high abundance and low evenness

The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,settlement ratesignificantlydifferedamong biofilmtreatments(p < 0.0001). A significant positive correlation between biofilm ageing and juvenile D. cristatum settlement was assessed (r=0.69 (p < 0.001), whereas the biofilm bacterial composition (relatively to the cultivable fraction) did not show any effect on the vermetid's settlement rate.

The establishment of non-indigenous species is one of the major threats to Mediterranean biodiversity. The tropical red macroalga Asparagopsis taxiformis is widely distributed in the Mediterranean Sea and appears invasive along the shallow rocky areas of western Sicily (Italy). Here it competes for space with the native brown macroalgae of the genus Cystoseira, in particular with C. brachycarpa, a valuable Mediterranean habitat former. This research aims to evaluate the potential effects of invasion of A. taxiformis on the polychaete assemblages associated with C. brachycarpa. Polychaetes were sorted from Cystoseira and Asparagopsis thalli collected along the Favignana Island (Sicily) in the rocky infralittoral algal community from four locations with different degree of invasion: 1) non-invaded, 2) invaded but dominated by Cystoseira, 3) invaded and dominated by Asparagopsis, 4) completely invaded. Ten replicates of each algal thalli were collected from two sites per location. Structure of polychaete assemblages changed significantly among degree of invasion. Reductions of average polychaete abundance and species richness occurred with invasion, with 58 individuals and 12 species per thallus on non-invaded location, only 4 individuals and 2 species on completely invaded location, and almost equal, intermediate values, on two partially invaded locations. Decrease of abundance was mainly caused by the decrease of sabellid Amphiglena mediterranea and syllids Syllis prolifera and Sphaerosyllis austriaca. These results raise concerns on the spread of non-indigenous habitat forming species and their potential impact on biodiversity at local scale.

A consistent living population of Panopea glycimeris (von Born, 1778) was documented underwater along the eastern coast of Sicily. Twenty specimens were counted over an area of 1000 m(2), with an estimated total population of less than 300 individuals. The morphometric measurements of an adult specimen captured are provided. Proposals to adopt protection measures for this species are discussed.

Mollusc assemblages of three concrete artificial reefs (ARs) in the Gulf of Castellammare were compared with those of two nearby natural reefs (NRs). The reefs were located in areas characterized by different degrees of water transparency, with average annual Secchi disk visibility ranging from clear (>20 m) to turbid waters (

ed. F Doumange

Biological invasions are a key driver of global change, affecting biodiversity and natural ecosystem functioning. Non-indigenous species (NIS) with significant established and expanding populations have the potential to become invasive, with serious environmental, socio-economic, and/or human health consequences. Mediterranean Islands (including Marine Protected Areas “MPAs”), important hotspots of biodiversity, are particularly vulnerable to NIS invasions. Understanding the effects of NIS species on biodiversity, as well as their current distribution and expansion trends, is therefore critical for creating effective conservation strategies. Here, we present three different case studies from Sicily (North-Western Mediterranean Sea) that highlight how NIS species interact with native species and the habitat where they settle. The first case study, carried out along the coast of Favignana Island (Egadi Islands MPA), highlights how the ability of Caulerpa cylindracea to form multi-layered mats trapping the sediment promotes the establishment of other NIS, including the biofouler worm Branchiomma bairdi. The second case study, performed along the North-Western coast of Sicily, shows how Halophila stipulacea can inhibit the growth of the co-occurring native seagrass Cymodocea nodosa. Finally, the third study case, undertaken along the coast of Favignana Island, highlights how the shift in habitat from the native Ericaria brachycarpa to the invasive Asparagopsis taxiformis may drastically erode primary producer biomass and associated biodiversity. Overall, our findings not only emphasize the negative effects of NIS on native habitats, but also confirm that MPA protection does not limit the introduction and spreading of NIS.

In late summer 2020, a widespread mortality event severely affected colonies of the Mediterranean endemic orange coral Astroides calycularis in the Pelagie Islands (Strait of Sicily, southern Mediterranean Sea). The degree of the mortality impact at seven study sites of the archipelago (five within the Pelagie Islands Marine Protected Area) was quantified by estimating the proportion of affected colonies in populations of A.calycularis. Five of the seven surveyed sites revealed a low degree of impact, but Punta Ruperta and Cala Creta (both on the island of Lampedusa) showed a medium impact with values of 32.3% and 30.5% of affected colonies respectively. The 2020 mortality event coincided with a longer lasting and warmer anomalous summer period, with sea surface water reaching the highest temperatures recorded in the last decade across the archipelago. Given the alarming climatic predictions for the near future, new mortality events could occur, causing potentially new local extinctions in the Mediterranean Sea. In this context, the role of marine protected area management becomes crucial to detect mortality events of vulnerable species.

Invasive seaweeds are listed among the most relevant threats to marine ecosystems worldwide. Biodiversity hotspots, such as the Mediterranean Sea, are facing multiple invasions and are expected to be severely affected by the introduction of new non-native seaweeds in the near future. In this study, we evaluated the consequences of the shift from the native Ericaria brachycarpa to the invasive Asparagopsis taxiformis habitat on the shallow rocky shores of Favignana Island (Egadi Islands, MPA, Sicily, Italy). We compared algal biomass and species composition and structure of the associated epifaunal assemblages in homogenous and mixed stands of E. brachycarpa and A. taxiformis. The results showed that the biomass of primary producers is reduced by 90% in the A. taxiformis invaded habitat compared to the E. brachycarpa native habitat. The structure of the epifaunal assemblages displayed significant variations among homogenous and mixed stands. The abundance, species richness and Shannon-Wiener diversity index of the epifaunal assemblages decreased by 89%, 78% and 40%, respectively, from homogenous stands of the native E. brachycarpa to the invasive A. taxiformis. Seaweed biomass was the structural attribute better explaining the variation in epifaunal abundance, species richness and diversity. Overall, our results suggest that the shift from E. brachycarpa to A. taxiformis habitat would drastically erode the biomass of primary producers and the associated biodiversity. We hypothesize that a complete shift from native to invasive seaweeds could ultimately lead to bottom-up effects on rocky shore habitats, with negative consequences for the ecosystem structure, functioning, and the services provided.

Marine Protected Areas (MPAs) are playing a central role in the achievement of ocean sustainability and, since 2000, their global coverage has increased over ten times. The success of MPAs, and therefore the delivery of their potential outcomes for human well-being and global sustainability, requires multi-disciplinary, holistic, and comprehensive approaches for its achievement. In this study, the global scientific literature on MPAs was quantitatively reviewed through bibliometrics approaches, investigating patterns and trends in its development over time. In particular, bibliometric network and citation burst analyses of keywords were performed using VOSviewer and CiteSpace software. The bibliographic search on the Scopus and Web of Science databases resulted in a total number of 5908 and 6036 scientific documents published on MPAs. The network analysis of the keywords co-occurrence produced four main clusters whose connections and overlapping showed a multidisciplinary structure of MPA science, in which the ecological, social, and economic domains of research are strongly interlinked. Temporal analyses showed a recent focus on topics related to the social-ecological systems theory (e.g., ecosystem services, marine spatial planning, governance, and small-scale fisheries) suggesting that newer research lines recognize the importance of integrating the “human dimension” in conservation and sustainability studies. Overall, the results of both the performed bibliometric analyses pointed out the evolution of MPA science from the conventional concept of “marine reserves” to a broader scope integrating ecological, economic, and social aspects. In conclusion, MPA research is timely responding to the identification of MPAs as ocean sustainability tools, opening MPA science to multi-disciplinary research lines by linking the ecological and socio-economic dimensions of sustainability. MPA research is expected to play a crucial role in generating the interdisciplinary scientific knowledge needed to fully contribute to global ocean sustainability and human well-being.

Vermetid bioconstructions are biogenic formations, built by sessile gastropod molluscs belonging to the family Vermetidae worldwide distributed, occurring in the intertidal and upper subtidal in the rocky shores. In the Mediterranean basin, they occur in complex and tridimensional structures that enhance the local biodiversity, allowing to qualify the structuring species as ecosystem engineers. Due to their ecological relevance and considerable extension along the coasts, we assessed their structural complexity using unmanned aerial vehicle (UAV) technology, as tool of littoral cartography analysis of these bioconstructions, and plaster hemispheres dissolution as a descriptor index of the water movement on them. We adopted an UAV to produce a very high spatial resolution map along 830m of rocky coast where these vermetid gastropods occur. Through an orthophoto with a GSD (Ground Sample Distance) of 1 cm, different complexity values of indentation degree (or roughness profiles) of the reef boundaries were detected, corroborating literature data carried out with traditional measurement techniques (e.g., tape measure). Our results indicate that the most complex zone of reef is the outer edge, facing the open sea, with a decreasing trend toward the inner edge. Concerning the experimental approach conducted using plaster hemispheres placed along the platform, it reveals that water movement is a structuring factor of the vermetid reef complexity along the rocky coast. Overall, the application of UAV technique allows an appropriate approach to analyze different zones of the vermetid reefs with a high-accuracy on a large spatial scale, greatly reducing sampling effort, and generating important implications for future monitoring and conservation programs.

International audience; Characterized by interlinked social, economic, and ecological dynamics, Marine Protected Areas (MPAs) are a management tool for achieving sustainability goals in social-ecological systems. The recent increase in their establishment worldwide, fostered by international policies, highlights the need for comprehensive and integrated assessment frameworks able to address the evaluation of their social-ecological effectiveness and management performance, which is of fundamental importance for their adaptive management and decision making processes. Although several indicators and methodologies exist to assess MPAs ecological or social performances, no comprehensive assessment framework currently captures their broad range of objectives, encompassing the ecological, socio-cultural, and economic spheres. In this study, we present a novel quantitative framework (named MPAs Overall Success Evaluation – MOSE) able to assess the overall effectiveness and management performance of MPAs under the perspective of social-ecological systems. The multicriteria framework includes indicators linked to nature conservation, socio-cultural, socio-economic, and management objectives, integrating the multidisciplinary knowledge on MPAs in a single but comprehensive approach. The proposed framework was applied to the case study of Cerbère-Banyuls Natural Marine Reserve (France), the first MPA included in the IUCN Green List. Results showed that a high level of management effort is applied to the investigated MPA, generating several social-ecological benefits. This study showed the applicability of the MOSE framework and its potential usefulness as a tool to inform managers and decision-makers in charge for developing adaptive management strategies.

Este artículo contiene 8 páginas, 4 figuras., Experiments have shown that increasing dissolved CO2 concentrations (i.e. Ocean Acidification, OA) in marine ecosystems may act as nutrient for primary producers (e.g. fleshy algae) or a stressor for calcifying species (e.g., coralline algae, corals, molluscs). For the first time, rapid habitat dominance shifts and altered competitive replacement from a reef-forming to a non-reef-forming biogenic habitat were documented over one-year exposure to low pH/high CO2 through a transplant experiment off Vulcano Island CO2 seeps (NE Sicily, Italy). Ocean acidification decreased vermetid reefs complexity via a reduction in the reef-building species density, boosted canopy macroalgae and led to changes in composition, structure and functional diversity of the associated benthic assemblages. OA effects on invertebrate richness and abundance were nonlinear, being maximal at intermediate complexity levels of vermetid reefs and canopy forming algae. Abundance of higher order consumers (e.g. carnivores, suspension feeders) decreased under elevated CO2 levels. Herbivores were non-linearly related to OA conditions, with increasing competitive release only of minor intertidal grazers (e.g. amphipods) under elevated CO2 levels. Our results support the dual role of CO2 (as a stressor and as a resource) in disrupting the state of rocky shore communities, and raise specific concerns about the future of intertidal reef ecosystem under increasing CO2 emissions. We contribute to inform predictions of the complex and nonlinear community effects of OA on biogenic habitats, but at the sametime encourage the use ofmultiple natural CO2 gradients in providing quantitative data on changing community responses to long-term CO2 exposure., This work contributes to the University of Palermo FFR-A project and the EU-FP7 MedSeA project (grant agreement no. 265103) to M.M.

We present the first dataset of meiofauna associated with vermetid reefs (biogenic constructions of Mediterranean intertidal habitat) in two areas along the northern coast of Sicily, Italy. The vermetid reefs are characterized by a horizontal extension from the shore towards the open sea and can be divided into three zones (the inner margin, the cuvette zone and the outer margin) which differ in hydrodynamic features. We studied the spatial distribution of meiofauna along the horizontal axis of the vermetid reefs, investigating the communities inhabiting the sediment inside cuvettes (shallow pools inside the “cuvette zone”) located between the inner and the outer margins of the reefs. We observed an increase in meiofaunal abundance from the inner to the outer part of the reef (from 1808 ± 80 to 2992 ± 512 ind. 100cm−2) in both areas. Moreover, we studied meiofaunal communities associated with the most abundant macroalgae (Cystoseira sp., Jania rubens, Palisada perforata, Dictyota sp. and Padina pavonica) living on the reefs, investigating the influence of habitat size (biomass) and identity (complexity) of macroalgae. We found that meiofauna varied in abundance (from 446 ± 51 to 1758 ± 231 ind. 100cm−2 on P. perforata and Cystoseira sp., respectively), on different macroalgae, and that the habitat size significantly influenced these abundances, but its effect was dependent on macroalgal identity. In fact, we observed a positive correlation between meiofaunal abundance and algal complexity (fractal dimension). The high algal cover in the “cuvette zone” of the reefs could contribute to make this zone more suitable for meiofauna, in particular close to the outer margin where we found more complex macroalgae (i.e. Cystoseira sp.). These results confirm that vermetid reefs, with their structural complexity, may play an important role in structuring benthic fauna in intertidal habitats.

Microbial films may provide physical and bio-chemical cues which positively affect the settlement dynamic of a variety of benthic marine organisms, driving the development of ecosystems. Also for the Mediterranean intertidal reef-builder Dendropoma cristatum (Biondi, 1859), biofilm maturity has been found to enhance the settlement pattern. However, the microbial diversity associated with these bioconstructions has never been described. This study investigates the D. cristatum reef bacterial assemblage composition and temporal evolution in two localities in the northwest of Sicily. Biological diversity of the reef-associated biofilm and of 3 progressively older biofims obtained on artificial surfaces exposed in the field was described by Automated Ribosomal Intergenic Spacer Analysis (ARISA). Out of 55 detected OTUs, only 6 were shared between the 2 localities. Hierarchical grouping of taxa abundance showed two major groups that separated the 2 localities. Within each group, reef-associated and experimentally obtained biofilms formed individual clades. SSU-rRNA NGS sequencing of the reef-associated biofilm is in progress. These data highlight high variability in biofilm composition at local scale and between development stages, possibly responsible for the progressive increase of settlement of the Mediterranean biogenic engineer Dendropoma cristatum.

Despite the ecological relevance of the vermetid bioconstructions in the Mediterranean, little is known about the early life stage of Dendropoma cristatum. This study describes the preference for settlement substrata from D. cristatumlarvae. A field experiment was carried out to test the suitability of crustose coralline algae (CCA), D. cristatumadults and two inorganic substrata as settlement surfaces. The number of settling larvae varied among the four treatments with higher settlement success on organic surfaces. CCA and D. cristatumindividuals seem to promote attachment of young larvae and to induce the metamorphosis in recruits. This is probably due to biological or physical properties of the preferred substrata which result essential for the early development of the vermetid bioconstruction.

The vermetid reef is an intertidal bioconstruction distributed in the warmest waters of the Mediterranean Sea, and is built by the gregarious vermetid gastropodDendropomaspp. cemented by the coralline red algae of the genusNeogoniolithon.Thisbiogenichabitatisonly generically protected under the European Habitat Directive, but to date it is not explicitly taken into account in many conservation plans. Despite the documented local extinction of Dendropomain the some Eastern Mediterranean locations, its role as habitat engineer and the high numbers of ecosystem services provided, vermetid reef is among the least known marine bioconstruction of the Mediterranean. We counted 112 reefs along the Mediterranean coast, 44 of which are located in the Eastern basin and rest in the Western sector. Among them 44% are theoretically protected, while 56% do not benefit from any form of protection. Excluding Sites of Community Importance, existing only in European Countries, only 32 reefs (28.5%) are included within a MPA or a coastal reserve. No protection at all is ensured in Algeria, Cyprus and Libya, while less than 50% of the reefs are protected in Italy, Malta, Spain, Morocco and Syria, and less than 20% is protected in Lebanon, Tunisia and Turkey. Our analyses suggest the need to enlarge action plans to provide a true protection for the vermetid reef and to develop a conservation strategy at a basin scale,implementing the monitoring of this neglected but ecologically relevant coastal key habitat.

Dendropoma cristatumreefs are key-intertidal habitats of the central Mediterranean. Knowledge onD. cristatumbiology is presently scant, particularly on its early life stage. The development of embryos occurs inside the maternal shell, and the crawling larvae settle on hard substrates shortly after hatching. Epilithic biofilm is known to have implications in the settlement of many marine invertebrates; however whether biofilm plays a role in driving the vermetid settlement is unknown. In this study the microbial assemblage ageing is tested as apotentialtriggerforD. cristatumsettlement. A field experiment was set-up to compare the larval settlement rate on removable limestone cubes (5x5x2 cm), covered by a 28-, 32-and 40-days old vs. a 4-days old biofilm. Limestone showed physical properties suitable forD. cristatumsettlement. Cubes were fixed in equal number along the seaward edge of two reefs (NW Sicily) and the vermetid recruits attached within a 20-day period were counted. Overall, 709 recruits were recorded on the cubes, 76.4% of which settling on 28-40 days and the rest on 4-d biofilmed cubes. The number of settlers on 28- and 32-d cubes was 6-7 fold higher than those of 4-d, and doubled (i.e. 14-fold) in 40-d. SEM observations revealed the higher biological complexity of the older biofilm, rich in diatoms and cyanobacteria embedded in a mucal web. Our findings suggest a key-role of biofilm ageing in the settlement preference ofD. cristatumlarvae. Molecular analyses are underway to identify microorganisms and metabolites potentially facilitatingD. cristatumsettlement.

Vermetid gastropods are coastal habitat engineers which build biogenic platforms typical of intertidal rocky shores of central and south -east of the Mediterranean. These bioconstructions create a secondary habitat which increases resource availability and space for organisms, locally transforming the environment and modifying coastal geomorphology. Biological characteristics and physical structure of these bioconstructions are commonly studied by field-based sampling. Nevertheless, a lot of time is required to collect data over large areas of reef, field conditions can impair data collection and direct reef image interpretation may be a challenge due to their intertidal position. In this study, a small RPAS is used to describe the macrostructure of two vermetid reefs in different areas: Capo Gallo (NW Sicily) and Favignana Island (W Sicily). 800 m of each reef have been surveyed by using high-resolution aerial orthophotomosaics (2cm/px). Detailed 3D maps have been realized for both reefs and the following measures of ecological relevance have been estimated: external rim length, internal rim length, surface of external rim (mq), cuvette surface (mq) and reef surface (mq). Index of external rim development and Index of internal rim development have been calculated as a relationship between a standardized linear length and the length of the external and internal rim respectively. Total area for Capo Gallo reef is 2563,26 mq; indexes of external and internal rim development are respectively 3,40 and 1,90. For Favignana, reef area is 1263,15 mq and indexes of external and internal rim development are respectively 2,56 and 1,80. These results reveal RPAS as a powerful tool for physical description of vermetid reefs and to calculate how this biogenic habitat shapes the coast and increases habitat complexity on rocky shores. This study, moreover, shows the high potential for RPAS technique to be applied for mapping vermetid reefs and to aid the management and conservation of natural systems, as required by the EU Strategy on Biodiversity which declares the necessity of mapping habitats and the ecosystem services they provide.