In blind valleys and flat karst areas, there are some temporary ponds of a Mediterranean nature. These shallow depressions alternate between a dry and a flooded phase every year, with the particularity of being connected to groundwater, thus prolonging the period during which water is stored in the ponds.

At the beginning of spring, we can see floating aquatic plants such as water buttercup (Ranunculus peltatus), with their leaves and flowers on the surface. This is followed by amphibious plants (e.g. Eleocharis palustris, Illecebrum verticillatum), which begin their vegetative development while still submerged and only flower when the water begins to disappear, persisting until the dry phase arrives (early summer).

As far as fauna is concerned, the temporary ponds serve as feeding and breeding grounds for various species of birds such as the solitaire (Cercotrichas galactotes), the grey kestrel (Elanus caeruleus) or the redshank (Oenanthe hispanica), various species of amphibians such as the pygmy newt (Triturus pygmaeus), the green warty toad (Pelodytes ibericus sp.) or the meridional vole (Hyla meridionalis). ) or the meridional damselfly (Hyla meridionalis) and invertebrates such as the scarlet dragonfly (Crocothemis erythraea), the purple dragonfly (Thrithemis annulata) or the emperor dragonfly (Anax imperator), the largest dragonfly in the Portuguese fauna, being crucial for the existence of some uncommon species with high conservation value.

Of the species that inhabit these ponds, the most emblematic stands out: Triops vicentinus, a species of shrimp from the branchiopod class, first identified in 2010 in the temporary freshwater ponds of the Vila do Bispo municipality, and which also has occasional sightings in the Geopark territory, namely in the Tunes and Paderne area. These organisms are known as living fossils because they have existed for more than 200 million years. They are temporary freshwater crustaceans known as “tadpole shrimps”.