Born in the ridge of the Montemuro mountain, and covering its steep slopes, the stream of Eiriz frames this mountainous landscape, through a complex agricultural mosaic, and creating several waterfalls on its way to the mouth at the river Paiva. The cascade of Tojosa is one of them, surrounded by leafy trees creating a paradisiacal setting. Following the PR1 – Trail of the Mills – one can observe the traditional walls and slate stairs, witnessing the best of traditional architecture of the region, as well as watermills from which the people of these mountains took advantage for centuries from the real power of water. This route is also possible to contemplate the Poço Negro (Negro´s pit), a succession of waterfalls carving the hard granite of the mountain.
The abundance of water in these parts, combined with the extensive farming activity that occurs here, give rise to a high diversity of fauna and flora. Here we can see several species of invertebrates such as the enigmatic praying mantis or the marsh fritillary butterfly that during its lifecycle uses the aromatic honeysuckles blooming here to lay their eggs and to feed during caterpillar stage. We can also see several species of amphibians such as the iberian frog, the marbled newt or the natterjack toad, and also reptiles like the iberian emerald lizard or the slow worm. At humid slopes it is possible to observe the dorset heath, also known as heather-shell characteristic species of locations with high humidity. Also present are the beautiful, hoop petticoat daffodil that here springs, and at drier and stony places, we can contemplate the endemic pedunculated anarrhinum plant with a very restricted distribution between the Vouga and the Douro rivers.
