L-Għadira s-Safra is a unique transitional coastal wetland supporting numerous rare organisms. It is particularly interesting since although primarily a saltmarsh it also supports animals normally found in freshwater.

L-Għadira s-Safra is situated between Qalet Marku and Għallis in Naxxar within a gently sloping rocky shore composed of lower coralline limestone formation. It supports floral and faunal assemblages that are typical of freshwater habitats during the wet season.

These assemblages are characterised by fluctuating salinity at other times. Vegetation is dominated by plantains such as Plantago crypsoides and Plantago macrorhiza as well as sea samphire (Crithmum maritimum) and golden samphire (Inula crithmoides).

L-Għadira s-Safra is one of only two localities for the locally endangered prickle grass (Crypsis aculeate), and the only known locality for the rare and endangered liverwort (Riella helicophylla).

This wetland also supports the rare tadpole shrimp (Triops cancriformis) and the fairy shrimps Branchipus schaefferi and branchipus visnyai, both having a restricted distribution in the Maltese islands. These rare animals are typical of freshwater conditions rather than the prevailing saline environment. The endangered woodlouse Tylos latreillei sardous is also present.

The Mediterranean bindweed (Cressa cretica), a rare dwarf shrub confined to saline marshlands, is also recorded from this site, together with the sea knotgrass (Polygonum maritimum). Both species have are endangered and have a restricted distribution in the Maltese islands.

Mepa scheduled l-Għadira s-Safra as a Level 1 Area of Ecological Importance and Level 1 Site of Scientific Importance with an associated Level 3 buffer zone as per Government Notice No. 288/95 in the Government Gazette dated May 5, 1995.