"Pian di Spagna" is a wide plain between the Lake of Mezzola and the Lake of Como, at the entrance of Valtellina and Valchiavenna. It´s a wetland of great naturalistic importance among the area of Sondrio, Lecco and Como.
The place is mainly overgrown with canes, mixed broad-leaf wood, wide pasture areas and corn fields.
Perfect place for many birds´ nidification, it is therefore an ideal setting for people who love nature and want to enjoy a quiet day not far from turist resorts.

Origin and features of the nature reserve

Its origin is recent, in geological terms.
In the Roman age the lake of Como and the present lake of Mezzola were together.
Later the river Adda deposited materials from its frequent flooding until forming the present "Pian di Spagna".
The two lakes kept anyway connected through the river Mera channel. The hydrogeological situation was not stable, continual flooding caused big trouble to local population.

Things got suddenly better in 1858, when a great draining was ended and the river Adda was channeled into the Lake of Como. A trail kept still on the land from the old winding way of the river. Even today cartography records the presence of low-light areas of big bight-shaped land. Other drainage interventions were done after 1858. The last important one in 1953 involved 119 hectares.
Today the reserve, totally 1.500 hectares wide, has three main components: paludal and hygrophilous spontaneous vegetation, the lake and cultivated fields.
 
The wider marsh is in the north side of Pian di Spagna and is connected with the lake of Mezzola. Other important tracts of land overgrown with canes are close to the lake of lago di Como, in Borgofrancone, along the Mera channel.
The main species is Phragmites australis.
From the natural environment the landscape slowly changes getting into areas where land was converted into mowing meadow, but common reeds and sedge-grass still exist, clear signs of its real nature.

Flora

The Natural Reserve "Pian di Spagna - Lago di Mezzola" is a complex ecosystem with canes, wet meadows and still cultivated fields.
The wider cane field is in the north side of the Pian di Spagna (Stalle della Poncetta). The main species is marsh reed (Phragmites australis) sometimes with the less common greater reed-mace (Typha latifolia). 
Rare and pretty water-lily (Nymphaea alba) and yellow water-lily (Nuphar lutea) are in Borgofrancone channel. Beyond the cane field, sedge-grass, a kind of narrow leaves plant, can be found gathered in thick tufts. The open field becomes then alder, willow, English oak wood and grazing land full of clovers, where , especially in autumn and spring, wild winds blow making the area even more fascinating.

Fauna

Many kinds of fish like perch (Perca fluviatilis), pike (Esox lucius), burbot (Lota lota), trout (Salmo trutta), lake shad (Alosa fallax) and eel (Anguilla anguilla) live in the waters of channels, river Mera and the lake of Mezzola. Channels, puddles and ponds are rich in frogs and toads. Among mammals there are hare, fox , bat and other kinds of tiny mammals like the field mouse (Apodemus sylvaticus); polecat (Mustela putorius) is very rare. The small population of deers is really interesting (Cervus elaphus), while we have no clear sings since the ´80 about the presence of the very delicate otter (Lutra lutra).
The real wealth of the Reserve is anyway made up by birds, nested and above all migratory. Among migratory and resident birds there are about 200 kinds of different species, like spotted crake (Porzana porzana), small sandpiper (Actitis hypoleucos), kingfisher (Alcedo atthis), the very rare bluethroat (Luscinia svecica), reed warbler (Acrocephalus scirpaceus), mash warbler (Acrocephalus palustris), penduline (Remiz pendulinus), and so on.
About 24 species of aquatic birds have been censused like little grebe (Tachybaptus ruficollis), great crested grebe (Podiceps cristatus), eared grebe (Podiceps nigricollis), grey heron (Ardea cinerea), cormorant (Phalacrocorax carbo), wild duck (Anas platyrhynchos), green-winged teal (Anas crecca), whistling duck (Anas penelope), gadwall (Anas strepera), spoonbill duck (Anas clypeata), dun-bird (Aythya ferina), pochard (Aythya fuligula), common merganser (Mergus merganser) and water-crow (Fulica atra).
A small wild population of mute swans (Cygnus olor) nests in the Reserve.

A bit of history

In the Roman age the lake of Como and the present lake of Mezzola were alltogether.
Lately the river Adda transported mud and drifts which gradually deposited in the area. The Pian di Spagna was formed. The two lakes were anyway connected through the river Mera.
Ramsar convention mentioned the Pian di Spagna among wetlands of international interest and the Italian government signed the convention in 1971.
Nevertheless, as it usually happens, it took a long time to found the reserve. In 1988 a managing consortium was founded among the municipalities of the mountain areas such as Western Upper Lario, Valchiavenna and Valtellina of Mobegno.