Values that credited its declaration
This is an area with significant wildlife, especially griffon vulture, is also an area with remarkable morphological elements (vertical drop of 200 m, important cliffs and overhangs, folds and tops …), without forgetting its variety botany, as a transition area between the Mediterranean world and the Atlantic.
Description of the countryside
Montes Obarenes represent the latest and most southern foothills of the Cantabrian Mountains and stand as a great natural seawall on the plains of la Bureba in Burgos. They have an exemplary structural relief Jurassic style and its maximum height is the Pan Perdido, with 1.237 m high. Limited on the north by the river Ebro, inside includes the hills of Oña, La Llana, Pancorbo, Arcena and properly called Montes Obarenes.
A series of beautiful and deep gorges are the main protagonists of the landscape. Gorge Pancorbo, sickles excavated by the Ebro in Sobrón, the narrow mountain pass carved by the river Oca in the proximity of Oña, the Tobera passage, throat open by the Purón river in the Arcena mountain range are the finest examples .
The richness of tree and shrub species growing in the area is due to its privileged location, straddling the Atlantic and Mediterranean biogeographical regions. In the abundant rocky cliffs of this protected landscape, especially in Sobrón sickle and Pancorbo mountain pass, true portal Natural Area, where have installed their nests a large number of birds of prey.
Few natural spaces can boast of holding therein as much cultural wealth of Montes Obarenes. From the history and art treasures of the town Oña, with its exceptional medieval monastery of San Salvador, to the remains of a unique military architecture in Pancorbo, and picturesque picture of the city of Frias, chaired by challenging his silhouette castle with its hanging houses and his equally famous fortified bridge over the Ebro river.
The complex and rugged terrain of this natural area with a wide range of exhibitions and slopes, the different types of soil and climate ambivalence provide a broad spectrum of bioclimatic possibilities for the installation of a variety of vegetation. The result is a real crossroads plant posed by living in a great diversity, richness and species mix of very different requirements. So live in the area with oaks beeches, oaks and cork oaks, maples and rowan, with juniper and arbutus, heather, gorse and genistas, with thyme and lavenders, and meadows with cereal land without forget the pine forests (wild, Corsican and Corsican) reflection of a strategic area of transition between two biogeographic regions: the Atlantic and the Mediterranean.
In this natural area has been cataloged a total of 128 species of vertebrates. 29 of them are mammals which include the bobcat, otter, muskrat musgaño whiteleg and the Pyrenees because of their vulnerability along with other more abundant species such as deer and wild boar. Of the 76 species of birds, 7 are very significant: golden eagle, eagle, Montagu’s harrier, common buzzard, turtle dove, owls and heron without forgetting the various species of migratory birds that can be observed in the Sobrón reservoir and its vicinity.
The territory occupied by the Obarenes Natural Mountains Area are a beautiful and varied landscape. Its main attraction is the numerous canyons and cut shaped by rivers, not to mention very different environments, from large bodies of water, forests, where beech with oak, holly with junipers, boxwood with madrone, oaks and pines and ferns Twins heather with screws, a spacious panoramic from the highest points; and along with these natural elements other artificial man introduced as are some urban centers: Frias, Ona, Pancorbo, Trespaderne, Santa Gadea del Cid and a number of medieval buildings (castles, hermitages, etc.).
The relief of this area constitutes the structural hinge linking the Cantabrian Mountains and the Pyrenees, and is the result of the action of a set of tectonic forces on a dressing of secondary and tertiary deposits of alternating soft marl facies, sandstones and clays, with little consistency and great plasticity with a hard limestone facies which form the structural framework. The axes of this structural support constitute the syncline forming Villarcayo, Tobalina Valley and the great groove of Tertiary Ebro-Rioja giving rise to the valley of La Bureba and Miranda Depression. The anticlinal folds oriented NW to SE set the major mountain ranges of this area, consisting of ridges and limestone vaults vertical walls extending between the valleys and depressions. The two morfoestructurales units are linked together by ortoclinales corridors that make up the gorges, cliffs and canyons, and cause different karst limestone that make up a landscape of contrasts.