Riserva Naturale Alto Merse

The Nature Reserve

The Nature Reserve, situated in the south-west of the town of Siena, includes a long stretch of river Merse and torrent Ricausa, most of torrent Rosia, and the last stretch of torrent La Gonna, all tributaries of river Merse. Most of the surrounding chains, and precisely those where the siliceous rocks belonging to Verrucano Group outcrop, is covered with deciduous woodlands dominated by the Turkey Oak, which well adapts to siliceous soils. In the lower part of the slopes, where the climate is cooler, the Sessile Oak grows together with the Turkey Oak. The chestnut groves represent, after the Turkey oak formations, the most widespread woodland habitat of the Nature Reserve. Their diffusion has been favored by man, who has selected the chestnut tree where it was already growing and has planted it where the soil and the climatic conditions allowed.

Most woodlands of the Nature Reserve are state-owned areas and have not been used for decades. This enabled the development of big-size trees housing a rich forest wildlife including three woodpecker species (Green Woodpecker, Great Spotted Woodpecker, and Eurasian Wryneck), obtaining their nest from the biggest trunks, and mammals of great conservation importance like the Wildcat, the European Pine Marten, and the Polecat.

In the north-western section of the Nature Reserve, the wide clearings – resulting from the past agricultural activities – represent ideal environments for the rare Four-lined Snake and for many birds of prey like the Short-toad Eagle, the Buzzard, and the Kestrel.

River Merse, surrounded by a well-developed strip of riparian vegetation dominated by willows and poplars, houses four endemic fish species: the Arno Goby, Squalius lucumonis, the Horse Barbel, and the South European Roach. The clear and cool waters of the minor watercourses house the Spectacled Salamander and the Italian Stream Frog, two amphibians exclusively living in the Italian peninsula, both indicators of non-polluted environments. Rather unique for the whole province of Siena is the presence, in the waters of torrent La Gonna, of the freshwater crayfish, a crustacean that has become very rare in Europe because of its use in cooking and that, for this reason, has a species of particular interest for the European Union. Torrent La Gonna also houses the Dice snake, a rare snake in the whole peninsula, predator of fish and frogs, present here with one of the few populations known for southern Tuscany.

• Territory
• Geology
• Vegetation
• Wildlife (Sheets)