Le aree umide salmastre della Tenuta di San Rossore (PI): zonazione e successione delle specie vegetali in relazione alla salinità del suolo

The study area, localized in north Tuscany (Parco di Migliarino, S. Rossore e Massaciuccoli - Italy), is characterized by wide retrodunal depressed plains. In these sites is evident a marked seasonal soil hydromorphy and a geomorphology related to coastal dynamism. These swampy areas, covering about 380 hectares, have a salt gradient that increases with the proximity to the sea. The distribution and ecology of phytocenosis is affected by the chemical-physical parameters of the substrate: populations of Salicornia patula on clay and salty soils, cenosis of Spartina juncea on sandy and moderately salty soils, Phragmites australis. on lime and freshwater soils . In this area the contiguity and interpenetration of taxa with different ecology (Lippia nodiflora, Cladium mariscus, Arthrocnemum macrostachyum, Limonium narbonense, Sporobolus pungens, Aster tripolium, Artemisia caerulescens, Hordeum maritimum, Juncus maritimus) allow to the development of an elevated number of species and consequently a high plant biodiversity. The variation of salinity related to seasonal hydromorphy of the soils, depends on the seasonal climate change (rainy winter and dry summer). This fact determines a high vegetation dynamism which brings not only to a different spatial distribution of vegetation but also to a seasonal succession of the phytocenosis.