Recent changes of macrophytes distribution in the Orbetello lagoon (Tuscany, central Italy)

In transitional ecosystems, both the distribution and the association of macrophytes could be used as indices of the ecological level. In the Orbetello lagoon we evaluated the macrophytes distribution and the relative dominances of major species relating observed trends to the harvesting boat activities and to the management strategies adopted to improve general circulation. In summer 2003 and 2009 we performed samplings in above 50 geo-referenced stations widespread inside both lagoon basins. Field activities were performed according to the methodological procedures proposed by Blanquet (1964) and modified by Pignatti (1953). Collected data were statistically analysed performing geo-referenced distribution maps of each specie applying the ordinary kriging techniques using the software Surfer 7.0. Obtained results evidenced a general expansion of the Phanerogams meadows and in particular of the specie Cymodocea nodosa throughout the lagoon basin with significant changes also in the macroalgae assessments. Observed changes were also significantly related to the harvesting activities