Direct and indirect biotic interactions driving community structure, can be positive, increasing the fitness of both partners, or negative, increasing the fitness of only one of the participant to the interaction. Moreover, both partners may produce an integration among them, thus giving rise to an association defined as symbiosis, with parasitism and mutualism as the two extremes of a symbiotic continuum. In the past, negative interactions have been considered more widespread within communities and responsible for most of their structures. By contrast, cooperative interactions have mainly approached with a descriptive aspect. Both parasitism and mutualism can evolve from a commensal interaction depending from the ecological context and have a different role in promoting evolution. In turn commensalism can evolve from epibiosis, a widespread phenomenon in marine benthic environment where the high spatial competition promotes the overgrowth of organisms. Therefore, epibiosis is the starting point for further evolution of different kind of interactions leading to an increasing of biodiversity.
In the Mediterranean, habitat-forming corals often characterize essential fish habitats. While their distribution is sufficiently known for the western basin, few data are available from the Central-Eastern Mediterranean Sea (CEM). This study fills this gap supplying the largest dataset ever built on the geographical and bathymetric distribution of the most relevant habitat-forming corals (Eunicella cavolini, Eunicella verrucosa, Eunicella singularis, Leptogorgia sarmentosa, Paramuricea clavata, Corallium rubrum and Savalia savaglia) of the CEM. Information collected from different sources such as literature, citizen science, and from the World Wide Web (WWW) was combined. Videos published on the WWW provided additional information on the presence of fishing lines and signs of damage, as well as on the distribution of purple and yellow-purple colonies of Paramuricea clavata. The study highlighted the impressive amount of information that the WWW can offer to scientists, termed here as Web Ecological Knowledge (WEK). The WEK is constantly fuelled by internauts, representing a free, refreshable, long-term exploitable reservoir of information. A quick and easy method to retrieve data from the WWW was illustrated. In addition, the distribution of corals was overlapped to marine protected areas and to the distribution of environmental conditions suitable for coralligenous habitats, fragile biogenic Mediterranean structures hosting complex assemblages in need of strict protection. The collected data allowed identifying priority areas with high species diversity and sites that are impacted by fishing activities. Supplied data can correctly address conservation and restoration policies in the CEM, adding an important contribution to ecosystem-based marine spatial planning. ; This is a post-peer-review, pre-copyedit version of an article published in Biodiversity and Conservation on 23 December 2017 (First Online). The final authenticated version is available online at: https://doi.org/10.1007/s10531-017-1492-8 ...
Aim: Marine bioconstructions such as coralligenous formations are hotspot of biodi‐ versity and play a relevant ecological role in the preservation of biodiversity by provid‐ ing carbon regulation, protection and nursery areas for several marine species. For this reason, the European Union Habitat Directive included them among priority habitats to be preserved. Although their ecological role is well established, connectivity pat‐ terns are still poorly investigated, representing a limit in conservation planning. The present study pioneers a novel approach for the analysis of connectivity in marine bioconstructor species, which often lack suitable genetic markers, by taking advantage of next‐generation sequencing techniques. We assess the geographical patterns of genomic variation of the sunset cup coral Leptopsammia pruvoti Lacaze‐Duthiers, 1897, an ahermatypic, non‐zooxanthellate and solitary scleractinian coral species common in coralligenous habitats and distributed across the Mediterranean Sea. Location: The Italian coastline (Western and Central Mediterranean). Methods: We applied the restriction site‐associated 2b‐RAD approach to genotype over 1,000 high‐quality and filtered single nucleotide polymorphisms in 10 population samples. Results: The results revealed the existence of a strongly supported genetic structure, with highly significant pairwise FST values between all the population samples, includ‐ ing those collected about 5 km apart from each other. Moreover, genomic data indi‐ cate that the strongest barriers to gene flow are between the western (Ligurian–Tyrrhenian Sea) and the eastern side (Adriatic Sea) of the Italian peninsula. Main conclusions: The strong differentiation found in L. pruvoti is similar to that found in other species of marine bioconstructors investigated in this area, but it strongly contrasts with the small differences found in many fish and invertebrates at the same geographical scale. All in one, our results highlight the importance of assessing con‐ nectivity in species belonging to coralligenous habitats as, due to their limited disper‐ sal ability, they might require specific spatial conservation measures.
Anthropogenic climate change, and global warming in particular, has strong and increasing impacts on marine ecosystems (Poloczanska et al., 2013; Halpern et al., 2015; Smale et al., 2019). The Mediterranean Sea is considered a marine biodiversity hot-spot contributing to more than 7% of world's marine biodiversity including a high percentage of endemic species (Coll et al., 2010). The Mediterranean region is a climate change hotspot, where the respective impacts of warming are very pronounced and relatively well documented (Cramer et al., 2018). One of the major impacts of sea surface temperature rise in the marine coastal ecosystems is the occurrence of mass mortality events (MMEs). The first evidences of this phenomenon dated from the first half of'80 years affecting the Western Mediterranean and the Aegean Sea (Harmelin, 1984; Bavestrello and Boero, 1986; Gaino and Pronzato, 1989; Voultsiadou et al., 2011). The most impressive phenomenon happened in 1999 when an unprecedented large scale MME impacted populations of more than 30 species from different phyla along the French and Italian coasts (Cerrano et al., 2000; Perez et al., 2000). Following this event, several other large scale MMEs have been reported, along with numerous other minor ones, which are usually more restricted in geographic extend and/or number of affected species (Garrabou et al., 2009; Rivetti et al., 2014; Marbà et al., 2015; Rubio-Portillo et al., 2016, authors' personal observations). These events have generally been associated with strong and recurrent marine heat waves (Crisci et al., 2011; Kersting et al., 2013; Turicchia et al., 2018; Bensoussan et al., 2019) which are becoming more frequent globally (Smale et al., 2019). Both field observations and future projections using Regional Coupled Models (Adloff et al., 2015; Darmaraki et al., 2019) show the increase in Mediterranean sea surface temperature, with more frequent occurrence of extreme ocean warming events. As a result, new MMEs are expected during the coming years. To date, despite the efforts, neither updated nor comprehensive information can support scientific analysis of mortality events at a Mediterranean regional scale. Such information is vital to guide management and conservation strategies that can then inform adaptive management schemes that aim to face the impacts of climate change. ; Funding. MV-L was supported by a postdoctoral contract Juan de la Cierva-Incorporación (IJCI-2016-29329) of Ministerio de Ciencia, Innovación y Universidades. AI was supported by a Technical staff contract (PTA2015-10829-I) Ayudas Personal Técnico de Apoyo of Ministerio de Economía y Competitividad (2015). Interreg Med Programme (grant number Project MPA-Adapt 1MED15_3.2_M2_337) 85% cofunded by the European Regional Development Fund, the MIMOSA project funded by the Foundation Prince Albert II Monaco and the European Union's Horizon 2020 research and innovation programme under grant agreement no 689518 (MERCES). DG-G was supported by an FPU grant (FPU15/05457) from the Spanish Ministry of Education. J-BL was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020.
