In the Val di Cecina territory there are three important protected areas - the Berignone Nature Reserve, the Monterufoli Caselli Nature Reserve and the Montenero Nature Reserve - on the whole they extend over an area of about 7100 hectares that crosses the territories of Pomarance, Monteverdi Marittimo, Montecatini Val di Cecina and Volterra.
The Monterufoli-Caselli Nature Reserve, which includes the regional forest complexes of Monterufoli and Caselli, is of great landscape and naturalistic importance due to the excellent state of conservation of the places, the presence of considerable biodiversity and interesting geological formations.
The vaste forestes and dense Mediterranean scrubs are cut through by a network of streams, notably the Sterza and the Trossa, together giving life to one of Tuscany’s most important wilderness areas.
Fallow deer, roe deer, mouflons and wild boars can be spotted, while sighting wolves, foxes, weasels, badgers, martens, martens and hares is more difficult, both due to the smaller number of animals present and the "character" of these species.
Among the birds, notable is the presence of Circaetus gallicus (Short-toed snake eagle).
The Cavallino di Monterufoli is an indigenous pony that lives in the wild.
The Reserve can be crossed with a quiet walk, thanks to a network of easy paths, or with more demanding excursions. Along the way there are remains of ancient mines, traces of an old railway and the Sterza Waterfall, from which the river then continues flowing creating small natural pools.