This dataset shows modelled spatial distributions of coralligenous outcrops, maërl beds across the Mediterranean Sea. These bioconstructions are typical Mediterranean underwater seascapes, comprising coralline algal frameworks that grow in dim light conditions. They are the result of the building activities of algal and animal constructors, counterbalanced by physical, as well as biological, eroding processes. Because of their extent, biodiversity and production, coralligenous and maërl habitats rank among the most important ecosystems in the Mediterranean Sea, and they are considered of great significance both for fisheries and carbon regulation. <br/> The dataset also shows modelled spatial distributions for <i>Posidonia oceanica</i>. <i>Posidonia oceanica</i> is endemic to the Mediterranean Sea, where it is the dominant seagrass.

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across the Mediterranean produced in the framework of MEDISEH derived from the compilation of published and unpublished information.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 We amended the data set with our own unpublished data (grey literature).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.