PianosaLab: C fluxes of agroecosystems of a small Mediterranean island

The Mediterranean region is likely to be severely affected by climate change. The global carbon (C) balance is a driver of climate change as well as climate controls the natural rates of C fluxes. Thus, it is of key importance to quantify ecosystem C balance. Mediterranean systems cover a large land area of Italy, contributing significantly to the national C inventories. Given the variety of systems and the degree of anthropogenic influences, accounting for natural C stocks/fluxes and modelling responses to climate change of Mediterranean systems is an extremely difficult task. The Island of Pianosa, in the Tuscan Archipelago National Park, is especially suited for this type of investigation, because of its very special topography and of the complete absence of anthropogenic C emissions. Pianosa is an excellent analogue for a typical Mediterranean ecosystem where the natural vegetation is currently colonising the abandoned agricultural land and a number of different vegetation typology are found. The experimental activities is devoted to parametrising carbon and water vapor fluxes of the different vegetation patches of the island, and to monitoring on a continuous basis mean carbon exchange of the island as a whole. A measuring tower was used for flux measurements, based on the well-known eddy covariance technique. The system is open-type, and made of a 3-way sonic anemometer and either a closed or and open-path fast response IRGA. Data are reported concerning NEE of some vegetation patches (macchia and formerly cropped areas) which demonstrate that these surfaces are active sinks during early summer. flux data of the entire composite system shows an elevated sink activity, thus suggesting that an active recolonization process of abandoned agricultural areas is taking place.