Trough the long journey of river Paiva, from Leomil mountains to its mouth in lugar do Castelo, into the Douro river, we can see in several places, false meanders formed by the passage of the river. The whimsical design that Paiva valley took (that resembles a retort) was conditioned by differential erosion between soft rock and more resistant rock. In this heavenly place, formed over millions of years by Paiva river, there is a curious habitat, the Adernal (green olive tree formation), which here is called Adernal da Retorta. This thermophilic vegetation type, dominated by green olive tree, is accompanied by other shrub species such as the strawberry tree or myrtle. These forests are a relic of the subtropical flora of the Tertiary period, and it has found in the Paiva valley a refuge to survive the period of glaciations.
Leafy riparian corridors combined with the surrounding woods and the fantastic river Paiva make this site rich in biodiversity. Riparian species such as the black alder, ash and willow dominate these galleries where you can observe the beautiful green olive tree formation, the royal fern and even more discrete species such as the violet, bluebells, or delicate daffodils, as the hoop petticoat daffodil.
The white throated dipper and the common kingfisher are two of the species of birds that can be seen here frequently patrolling the Paiva. The otter, the iberian emerald lizard and the amphibians, common toad and iberian frog, are also examples of the wealthy fauna present here. In the surroundings, we can also find species of great value, such as the rare feather pink or the lush solomon’s seal.
