The Alviano Oasis is one of the most important wetland areas in central Italy, a unique treasure chest of biodiversity.

Located between the municipalities of Alviano, Guardea, Montecchio and Civitella d’Agliano, on the border between Latium and Umbria, it was created to protect a corner of the Tiber that has been modified and transformed by man. The reserve is part of the Tiber River Park and includes all the environments typical of freshwater wetlands and preserves environments that mostly disappeared more than a century ago.

It covers about 900 hectares, divided into a marshy area of about 500 hectares and over 300 hectares of hygrophilous woodland, as well as water meadows and ponds. Thanks to the diversification of the environments, the reserve is inhabited by over 200 species of birds, both migratory and resident, including coots, marsh harriers, kingfishers, grebes and numerous ducks.

The Alviano Oasis, in addition to being a fundamental stopover area during migratory passage, is also a site of particular interest for nesting. It hosts one of the most important heron nesting areas in Italy, where the cattle heron, the black-crowned night heron, the grey heron, the little egret and the squacco heron nest, with a total of over 200 nests. Among the mammals, the Oasis is inhabited by fox, badger, porcupine, hedgehog, marten and European squirrel and the rare wild cat. The presence of numerous amphibians is important, including the green frog, the Dalmatian frog, the spotted newt and the great crested newt. Among the reptiles, it is home to the collared grass snake, four-lined snake, the green whip-snake and the elusive slow worm (Anguis fragilis).

The reserve is well equipped with huts for birdwatching and nature photography, with an observation tower and an open-air classroom, right in the middle of the marsh, for a total of 12 facilities, including an educational workshop for schools.

There are two nature trails. The first (Main Nature Trail) is 1.5 km long and runs partly along the marsh and then into the hygrophilous forest and is accessible to all. The second, Sentiero Vecchio (Old Nature Trail) is 3.5 km long, runs along the course of the Tiber River within the hygrophilous forest and allows a wilder approach to the reserve. It is possible to join the two paths and walk a loop of about 7 km.