Assessment of the ecological quality (EcoQ) of the Venice lagoon usingthe structure and biodiversity of the meiofaunal assemblages

Transitional Environments (TEs) have been deeply modified to meet human requirements, and for thisreason are currently ranked among the most endangered aquatic ecosystems. The Adriatic basin hosts alarge number of TEs of which the Lagoon of Venice is the largest one, but information on its meiofauna arevery dated or focused to localized areas. The present study is the first to document the spatial distributionof meiofauna in the whole Venice lagoon. Furthermore, the health status of the TE of Venice has beenassessed by means of several faunal parameters (richness, diversity indices, structure of the entire meio-faunal assemblage and only rare taxa). All the univariate meiofaunal parameters (i.e. richness, diversityindices, Ne:Co ratio) were consistent in highlighting the worst ecological quality of the Porto Margheradistrict. Instead, the structure of the entire meiofaunal assemblage as well as that of rare taxa seemed todetect variations not directly related to pollution and likely due to the different hydrodynamic conditionsof Lido and Malamocco inlets. On the basis of our results, we have also critically discussed the usefulnessof the various faunal parameters in the monitoring assessment of the TEs.