This is a mid-mountain area of some 400m located on the western extension of Sierra de Aracena. It features a varied topography of linear mountains with thick vegetation, deep ravines and rich riverbank forests along Ribera del Aserrador River Pine, eucalyptus and oak forests, scrub thick rockrose scrubland and well preserved riverbank vegetation is its main plant formations.

There are large areas of land, modified by man, where the native vegetation has been replaced by pine and eucalyptus arranged in terraces for the pulp industry. Forest exploitation has been the main resource of the sparse population in the area, which was concentrated in forest villages like El Centinela and El Mustio.

This natural area is known because it hosts one of the largest bird colonies of black vultures in the Iberian Peninsula. This huge bird of prey can be observed from the peaks of Pelada, Mármol o Mojón along with other endangered species like Black Stork.

Besides the black vulture, other breeding species in the area are golden eagle, eagle owl, short-toed eagle and booted eagle. Other birds of prey such as spanish imperial eagle often fly this mountain ranges.

Featured species: black vulture, griffon vulture, golden eagle, spanish imperial eagle, short-toed eagle, eagle owl, crag martin, black-eared wheatear, melodious warbler, dartford warbler, orphean warbler, golden oriole, rock sparrow, rock bunting.