Riserva Naturale Senese del Basso Merse
The Basso Merse Reserve has an area of 1,478 hectares almost completely contained in the Sienese territory and includes the last kilometres of the Merse river, the final stretch of the Farma river.
The landscape is mainly flat with modest hills no higher than 400m and wide flatlands with farms and rivers.
The part of the park that falls within the Valle del Torrente Crevolone, the landscape is rugged and mostly forests. The Mediterranean scrub and the holm oak dominate the vegetation of these hills, along with native flora and numerous outcrops of serpentinite, a dark green rock used in Romanesque architecture.
The park includes the Pietriolo Hot Springs and sections of the countryside around Civitella Paganico.
One of the reasons for the establishment of the Reserve is to protect the rich river habitat of the Merse, among the last in Tuscany to host a very rare breed of otter, the mammal with the highest risk of extinction in Italy.
The river system is also home to kingfishers and important amphibian specie like the emerald toad, a species typical of the coastal territories and the spectacled salamandrine, endemic to the Italian peninsular.