Benthic communities were studied twice (during the autumn and spring) in three Mediterranean coastal lagoons located in Greece (Logarou) and Italy (Cesine and Grado-Marano). The species composition and distribution, community diversity, species richness, dominant taxa and their ecological identity, benthic trophic and biomass size structure were investigated in these lagoons and the results were correlated with the environmental variables. The overall similarity based on species composition and abundance among the lagoons was low due to the differences in the dominant environmental factors, whereas the variations in the community diversity and species richness were mainly related to the degree of marine influence, reflecting the natural structure. The benthic classification indices AMBI, M-AMBI, BENTIX, BO2A, ISD and ISS were applied to assess the ecological status of the lagoons studied. The results revealed that the biotic indices AMBI, M-AMBI, BENTIX, and BO2A were not adequately efficient due to the natural dominance of the tolerant and opportunistic species and the correlation of the species diversity with natural stress. The ISD and ISS, on the other hand, based on size distribution frequencies and on size spectra sensitivity, respectively, showed good discrimination power among the impacted and unimpacted sites. The results indicate that except for species sensitivity, other traits of the communities such as the biomass or size structure could be more robust, sensitive and suitable for assessing the ecological quality of lagoons.
The present study reports on the occurrence of two specimens of the alien species Polydora cornutaBosc, 1802, in Elefsis Bay, the Saronikos Gulf (Aegean Sea, eastern Mediterranean). This is the firstrecord of this invasive alien species on the coast of Greece and the second report in the eastern MediterraneanSea after its first finding in Izmir Bay (on the Turkish Aegean coast). This finding enhances its distributionalpattern within the Mediterranean
During the last decade the Water Framework Directive (WFD) has driven scientific community endeavours towards the development of assessment tools to determine the Ecological Quality Status (EQS) for all surface waters, including transitional waters (TWs). Macroinvertebrates being used as Biological Quality Elements encouraged the development of distinct multimetric and multivariate indices, initially based on taxonomic approaches. Those indices were mostly developed for the marine environment and applied extensively on TWs. The main discrepancies in the ecological quality status assessment arise on TWs, partially due to the difficulty in discriminating the effects of natural stress from anthropogenic impact. As a response, indices following functional approaches are being developed and applied in assessing the EQS in these environments. Next, the validation and intercalibration of the metrics as well as the settlement of reference conditions are additional sources of variability inherent to any assessment. This paper aims at briefly presenting the different steps needed for the implementation of WFD on Mediterranean TWs. It highlights existing difficulties and possible research lines to be explored in order to reduce sources of variability and better assess the status of such water bodies.
Benthic macroinvertebrate communities form the basis of the intricate lagoonal food web. Understanding their functional and taxonomic response, from a β-diversity perspective, is essential to disclose underlying patterns with potential applicability in conservation and management actions. Within the central lagoon of Messolonghi we studied the main environmental components structuring the macroinvertebrate community. We analyzed the β-taxonomic and β-functional diversity across the main habitats and seasons, over a year time frame. Our results outline habitat type and vegetation biomass as the major factors structuring the communities. We found environmental variability to have a positive correlation with functional β-diversity, however no correlation was found with taxonomic β-diversity. Across the seasons an asynchronous response of the functional and taxonomic β-diversity was identified. The taxonomic composition displayed significant heterogeneity during the driest period and the functional during the rainy season. Across the habitats the unvegetated presented higher taxonomic homogeneity and functionally heterogeneity, contrary the vegetated habitats present higher taxonomic variability and functional homogeneity. Across the seasons and habitats a pattern of functional redundancy and taxonomic replacement was identified. Besides high functional turnover versus low taxonomic turnover was documented in an anthropogenic organically enriched habitat We conclude that habitats display independent functional and taxonomic seasonal patterns, thus different processes may contribute to their variability. The framework presented here highlights the importance of studying both β-diversity components framed in a multiscale approach to better understand ecological processes and variability patterns. These results are important to understand macroinvertebrate community assembly processes and are valuable for conservation purposes.
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