Sant’Andrea Island has a flat limestone surface at an average height of about 2 metres above sea level. Its rocky coasts are ‘priority habitats’ as they consist of salt steppes of glasswort and the endemic species of sea-lavender (Limonium japygicum).
This park is the only nesting colony along the Italian Adriatic and Ionian coasts of Audouin’s gulls (Larus audouinii), an endemic species of the Mediterranean basin; this gives the park an international importance.
The coast of Punta Pizzo includes many different environments that form an interesting natural mosaic of Mediterranean maquis, Mediterranean pseudo-steppes, wetlands and marshes.
This wide range of environments accounts for the presence of different plant species, from high and low Mediterranean maquis (strawberry tree, Italian buckthorn, tree heath, thorny broom, myrtle, mastic, daphne, thorny asparagus) to garrigue plants (rosemary, thymus, mastic, tree heath, thorny broom) and widespread innermost grassland vegetation (orchids, including the vary rare Italian orchid, pot marigold, blessed thistle, common daisy, etc.).
Two very rare species of tree legumes can be found in the park: Anthillis hermanniaie, which grows in Punta Pizzo and nowhere else in the Salento peninsula, and stinking bean trefoil (Anagyris foetida).
The park encompasses a remarkable number of habitats of Community interest (as many as nine habitats, including five priority habitats) with outstanding features. The vegetation behind the dunes and wetland vegetation have a major importance.
Wetlands like the Li Foggi channel and the surrounding marsh areas are home to the rare Ipomoea sagittata species and they are also a staging post for aquatic birds during migrations.
Some black-winged stilts have been spotted recently, which means they sometimes nest in the park.