Domaine de Guidou

Domaine de Guidou is a protected natural site of 85 hectares located in the municipality of Sciez, on the shores of Lake Geneva. Classified as Natura 2000, it is owned by the Conservatoire du Littoral et des Rivages Lacustres and is managed collectively by the municipality of Sciez, LPO Auvergne-Rhône-Alpes, the ONF, and the Guidou Estate Management Association. The site comprises a mosaic of habitats: wooded areas, cereal crop fields, wet and dry meadows, and reed beds.

One of the most remarkable features of Domaine de Guidou is the presence of fossil sand dunes at Bois du Vernay, a formation found almost nowhere else in Europe. Until the 18th century, wind action on exposed lake sandbars created dunes similar to those found on seaside beaches. Although regulation of the lake level since the 20th century has slowed this process, the dunes remain visible in the landscape, now covered with vegetation.

The estate is home to 520 recorded plant species, including rare arable weeds (linked to cereal cultivation) now vulnerable due to pesticide use. The shallow depth of the lake in the Coudrée bay also makes it the most important site on French shores for wintering waterfowl: tufted ducks and pochards gather by the thousands each year, accompanied by goldeneyes. In spring, numerous waders (sandpipers, plovers) and herons (egrets, herons) make stops here during migration.