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    CIGESMED for divers: Establishing a citizen science initiative for the mapping and monitoring of coralligenous assemblages in the Mediterranean Sea
    (Pensoft Publ, 2016) Gerovasileiou, Vasilis; Dailianis, Thanos; Panteri, Emmanouela; Michalakis, Nikitas; Gatti, Giulia; Sini, Maria; Dimitriadis, Charalampos; Issaris, Yiannis; Salomidi, Maria; Filiopoulou, Irene; Dogan, Alper; d'Avray, Laure Thierry de Ville; David, Romain; Cinar, Melih Ertan; Koutsoubas, Drosos; Feral, Jean-Pierre; Arvanitidis, Christos
    Background Over the last decade, inventorying and monitoring of marine biodiversity has significantly benefited from the active engagement of volunteers. Although several Citizen Science projects concern tropical reef ecosystems worldwide, none of the existing initiatives has yet specifically focused on their Mediterranean equivalents. Mediterranean coralline reefs, known as "coralligenous", are bioherms primarily built by calcifying rhodophytes on hard substrates under dim-light conditions; they are considered hotspots of biodiversity and are extremely popular among divers due to their complex structure, conspicuous biological wealth and high aesthetic value. Nevertheless, data on their distribution, structure and conservation status is lacking for several Mediterranean areas while they are vulnerable to an increasing number of threats. New information In the framework of CIGESMED SeasEra (ERAnet) project a specialized Citizen Science project was launched, aiming to engage enthusiast divers in the study and monitoring of Mediterranean coralligenous assemblages through the gathering of basic information regarding their spatial occurrence, assemblage structure and associated pressures or threats. For its active implementation, a data collection protocol and a multilingual website were developed, comprising an educational module and a data submission platform. Georeferenced data reporting focuses on: (a) basic topographic and abiotic features for the preliminary description of each site, and the creation of data series for sites receiving multiple visits; (b) presence and relative abundance of typical conspicuous species, as well as (c) existence of pressures and imminent threats, for the characterization and assessment of coralligenous assemblages. A variety of tools is provided to facilitate end users, while divers have the choice to report additional information and are encouraged to upload their photographs. The long-term goal is the development of an active community of amateur observers providing widespread and ecologically significant data on coralligenous assemblages.
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    Coralligenous assemblages along their geographical distribution: Testing of concepts and implications for management
    (Wiley, 2020) Cinar, Melih Ertan; Feral, Jean-Pierre; Arvanitidis, Christos; David, Romain; Taskin, Ergun; Sini, Maria; Katagan, Tuncer
    The coralligenous habitat was studied at the large Mediterranean scale, by applying a standardized, non-destructive photo-sampling protocol, developed in the framework of the CIGESMED project. the results provided evidence to support the following statements: (a) the assemblage pattern is not homogeneously distributed across the four Mediterranean ecoregions studied (biotic gradients hypothesis); and (b) the assemblage pattern does not change significantly when the information is aggregated to higher taxonomic levels (taxonomic sufficiency hypothesis). Surrogate taxonomic categories higher than species, such as genus and family, can be used to reveal the multivariate pattern of the coralligenous assemblages. Although preliminary at the pan-Mediterranean scale, these outcomes set the scene for future comparisons as more data sets become available but also for comparisons between taxonomic and functional patterns. 1.2.3.4.
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    Ecoregion-Based Conservation Planning in the Mediterranean: Dealing with Large-Scale Heterogeneity
    (Public Library Science, 2013) Giakoumi, Sylvaine; Sini, Maria; Gerovasileiou, Vasilis; Mazor, Tessa; Beher, Jutta; Possingham, Hugh P.; Abdulla, Ameer; Cinar, Melih Ertan; Dendrinos, Panagiotis; Gucu, Ali Cemal; Karamanlidis, Alexandros A.; Rodic, Petra; Panayotidis, Panayotis; Taskin, Ergun; Jaklin, Andrej; Voultsiadou, Eleni; Webster, Chloe; Zenetos, Argyro; Katsanevakis, Stelios
    Spatial priorities for the conservation of three key Mediterranean habitats, i.e. seagrass Posidonia oceanica meadows, coralligenous formations, and marine caves, were determined through a systematic planning approach. Available information on the distribution of these habitats across the entire Mediterranean Sea was compiled to produce basin-scale distribution maps. Conservation targets for each habitat type were set according to European Union guidelines. Surrogates were used to estimate the spatial variation of opportunity cost for commercial, non-commercial fishing, and aquaculture. Marxan conservation planning software was used to evaluate the comparative utility of two planning scenarios: (a) a whole-basin scenario, referring to selection of priority areas across the whole Mediterranean Sea, and (b) an ecoregional scenario, in which priority areas were selected within eight predefined ecoregions. Although both scenarios required approximately the same total area to be protected in order to achieve conservation targets, the opportunity cost differed between them. The whole-basin scenario yielded a lower opportunity cost, but the Alboran Sea ecoregion was not represented and priority areas were predominantly located in the Ionian, Aegean, and Adriatic Seas. In comparison, the ecoregional scenario resulted in a higher representation of ecoregions and a more even distribution of priority areas, albeit with a higher opportunity cost. We suggest that planning at the ecoregional level ensures better representativeness of the selected conservation features and adequate protection of species, functional, and genetic diversity across the basin. While there are several initiatives that identify priority areas in the Mediterranean Sea, our approach is novel as it combines three issues: (a) it is based on the distribution of habitats and not species, which was rarely the case in previous efforts, (b) it considers spatial variability of cost throughout this socioeconomically heterogeneous basin, and (c) it adopts ecoregions as the most appropriate level for large-scale planning.
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    How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities
    (Peerj Inc, 2018) Thanopoulou, Zoi; Sini, Maria; Vatikiotis, Konstantinos; Katsoupis, Christos; Dimitrakopoulos, Panayiotis G.; Katsanevakis, Stelios
    Background: Underwater visual surveys (UVSs) for monitoring fish communities are preferred over fishing surveys in certain habitats, such as rocky or coral reefs and seagrass beds and are the standard monitoring tool in many cases, especially in protected areas. However, despite their wide application there are potential biases, mainly due to imperfect detectability and the behavioral responses of fish to the observers. Methods: The performance of two methods of UVSs were compared to test whether they give similar results in terms of fish population density, occupancy, species richness, and community composition. Distance sampling (line transects) and plot sampling (strip transects) were conducted at 31 rocky reef sites in the Aegean Sea (Greece) using SCUBA diving. Results: Line transects generated significantly higher values of occupancy, species richness, and total fish density compared to strip transects. For most species, density estimates differed significantly between the two sampling methods. For secretive species and species avoiding the observers, the line transect method yielded higher estimates, as it accounted for imperfect detectability and utilized a larger survey area compared to the strip transect method. On the other hand, large-scale spatial patterns of species composition were similar for both methods. Discussion: Overall, both methods presented a number of advantages and limitations, which should be considered in survey design. Line transects appear to be more suitable for surveying secretive species, while strip transects should be preferred at high fish densities and for species of high mobility.