A lake, with associated reedbeds (Phragmites) and wet meadows, and woodlands, hedgerows and cultivated land.
The site holds 20,000 or more waterbirds on passage and in winter, on a regular basis. Species of global conservation concern that do not meet IBA criteria: Aythya nyroca (wintering); Crex crex (passage).
BirdLife International (2019) Important Bird Areas factsheet: Lac de Grand-Lieu. Downloaded from http://www.birdlife.org on 16/12/2019.