The dataset of seagrasses distribution across the Mediterranean produced in the framework of MEDISEH derived from the compilation of published and unpublished information. For example literature search was made using mainly the ISI Web of Knowledge engine. At the same time a new search started from the “Bibliographic References” at the end of each paper. We amended the data set with our own unpublished data (grey literature). Moreover, we included data from reports of national and EU research projects and data networks. A major contribution to the improvement of our knowledge on seagrasses in the Mediterranean and especially <i>Posidonia</i> derived from the establishment of Natura 2000 network.

This dataset contains records of polychaetes from intertidal rocky shores in the Mediterranean Sea.

A lot for information has been derived from three critical sources: the first is the Action plan for the conservation of the coralligenous and other calcareous bio-concretions in the Mediterranean Sea by the UNEP-MAP-RAC/SPA (2008) followed by the report in the State of knowledge of the geographical distribution of the coralligenous and other calcareous bio-concretions in the Mediterranean by UNEP (2009). Together with these two initiatives, at present, there are other projects carried out at national and international scale focusing on bioconstructions, their distribution and the driving forces affecting their structure and function.