The poço Azul is also a paradise for biodiversity. The rare lesser purple emperor butterfly makes this valley home, presenting us with its amazing colors in shades of violet. In waterfalls and withewaters, the white-throated dipper feeds on the many macroinvertebrates that inhabit these waters. Higher up, the cyclamen-flowered daffodil takes advantage of deep and dark soils by the river to grow. At oak forests, the fire salamander and the slow worm feed on small inverte brates. The beautiful demoiselle dragonfly appears among the leaves of alder, showing its metallic green (female) and metallic blue colors (male).
On the hillside, some common holly trees dot the field and the three bird toadflax abound along the paths. These species are characteristic of mountain rivers and forests with great value for nature conservation. Of these, some are protected in Europe (common holly and daffodil), others are very rare (lesser purple emperor), and others are indicators of well-maintained ecosystems (belle demoiselle, slow worm and fire salamander).