Lebna is the largest and probably the most important of the artificial reservoirs of the northern Cap Bon peninsula, with the most extensive vegetation along the two streams which flow into it and which are dammed; there are extensive stands of Phragmites communis, Typha angustifolia and Juncus spp., which provide nesting habitat and cover for many waterbirds.
See Box for key species. Regular breeding species include Oxyura leucocephala (20–50 birds also winter) and Marmaronetta angustirostris (50–100 birds winter), as well as Porphyrio porphyrio, together with species such as Tachybaptus ruficollis, Podiceps cristatus and Fulica atra.Elaneus caeruleus breeds in the vicinity. Being situated near the tip of Cap Bon, Lebna, to some extent, replaces the drained former marsh of Garaet el Haouaria, and attracts a good number and variety of passage waterbirds, including species such as Plegadis falcinellus, Platalea leucorodia, storks, waders and terns. Several hundred Aythya nyroca regularly occur as post-breeding migrants. Wintering waterbirds include Anas platyrhynchos, A. acuta, A. penelope, A. clypeata, A. strepera, Aythya fuligula, A. ferina and Fulica atra, with total numbers of up to 20,000.
Non-bird biodiversity: None known to BirdLife International.