Valle Averto natural oasis extends for nearly 200 ha on the southern part of the Venetian lagoon in the locality of Lugo di Campagna Lupia. It is a biotope that was commissioned to be managed by the WWF. Its international importance has been acknowledged by the Ministry of the Environment and it is on the list of "fishing valleys", or lagoon wetlands which for centuries have been used for lagoon fish breeding.

This delicate and unique ecosystem constitutes an important place for resting, feeding, hibernation and nesting for numerous aquatic bird species. Amidst the reed thickets, mirrors of freshwater and saltwater and glades of poplars, elms and ash trees, camouflaged walking paths and observation towers have been set up to allow birdwatchers and visitors to watch birds without disturbing their quiet habitat.

During the spring and summer, there are numerous species (some considered rare) that choose the Oasis for nesting, such as the red heron, the red-crested pochard, the western marsh harrier, the common stilt and the kingfisher. Yet in the winter is when Valle Averto registers the largest number of specimens that come here to hibernate, including the white heron and grey heron, buzzard and the rare spotted eagle ray.

In the wooded areas of the Oasis, dwellings of small mammals have been found. The visit to Valle Averto also includes a stop at the nearby Museo del Territorio delle Valli e della Laguna di Venezia [Museum of the Valleys and Lagoon of Venice] which has collections of artefacts, gears, pictures and documents about fishing and life in the Venetian lagoon fish breeding areas.