The waters of the River Vero continue to Barbastro. After passing through the capital of the Somontano, the river joins with the Cinca in La Boquera. Here gypsum and soluble salts emerge, which don't exist in the rest of the river basin and which permit the growth of vegetation suited to semi-arid environments.
The convergence of several ecosystems in such a limited space (escarpments of gypsum, riverside vegetation and the river course of the Vero and the Cinca) make it possible for La Boquera to have the richest concentration of fauna in all of the Cultural Park.