Nature
Nature, biodiversity and balance
Protected nature
Welcome to the Sierra de Guara. You are about to enjoy an extraordinary experience, for you have arrived in a place blessed by nature, rock and water. Its vast territory is recognised both nationally and internationally through conservation measures that highlight its valuable, unique and spectacular landscapes and ecosystems. Unique geological formations, rivers and ravines, exclusive plant species, exceptional forests and trees, a wealth of birdlife and a human landscape that has left a distinctive heritage, with traces dating back to the earliest days of humanity, make this area one of the most admired and sought-after in southern Europe.
Guara is situated on the southern edge of the Pyrenees, in the so-called Pre-Pyrenean mountain ranges of Upper Aragon. It lies at the heart of the province of Huesca, straddling four regions that are delighted to offer you their attractions for the enjoyment of locals and visitors alike:
- Alto Gállego www.comarcaaltogallego.es
- Sobrarbe www.sobrarbe.com
- Hoya de Huesca Comarca de la Hoya (hoyadehuesca.es)
- Somontano de Barbastro www.somontano.org
Here in the Sierra y Cañones de Guara Natural Park. Government of Aragon (aragon.es) you can find all the general information you need, as well as details of the existing interpretation centres (Bierge, Arguis and Santa Cilia), and, very importantly, learn that there is a Board of Trustees or governing body and a range of management tools designed to ensure the conservation and management of Guara’s natural resources, but also to promote the sustainable development of the villages and people who live here.
It was from the 1970s onwards that the growing influx of visitors to the Sierra de Guara – who did not always treat that wild natural environment with respect – prompted the first calls for its preservation and led, in the late 1980s, to the establishment of a natural park which was finally designated as a protected area in 1990: the Sierra y Cañones de Guara Natural Park. Covering an area of 47,453 hectares, plus a further 33,286 hectares of the Peripheral Protection Zone, it is the largest Protected Natural Area in Aragon, far surpassing other iconic sites of Aragonese nature such as Ordesa and Monte Perdido, Posets-Maladeta and Moncayo.
Spain’s membership of the European Union also entails a series of conservation requirements and responsibilities. The outstanding natural values of the Sierra de Guara mean that it forms part of the wider network for the preservation of natural areas and species in Europe, the Natura 2000 network. And in two ways: Special Protection Area for Birds (SPA), under the EU Birds Directive, and Site of Community Importance (SIC), under the Habitats Directive, https://www.aragon.es/-/red-natura-2000 In 2021, the Management Plans for these designations were approved, designating Guara as a Special Area of Conservation (SAC), a true European benchmark.
Further international recognition adds to the region’s impressive track record, as the Sobrarbe-Pyrenees Geopark / Pyrenees Geological Park (geoparquepirineos.com) , a designation from the United Nations Educational, Scientific and Cultural Organisation (UNESCO), recognises the extraordinary geological heritage of the Sierra de Guara area, situated on the southern edge of the Sobrarbe region. As you will see throughout the mountain range, the geopark designation fits perfectly with the essence of Guara, a vast rocky framework upon which its renowned canyons have been carved.
Mountains, gorges and rock formations
The Natural Park takes its name from Guara, a mountain range about 15 km long that stretches from west to east between the rivers Guatizalema and Alcanadre. This is where the highest peak in the range is found, the Tozal de Guara (2,077 m). Flanking Guara, but running north-south, are the Gabardiella, Arangol, Balcez and Sebil ranges, which reach altitudes of around 1500–1600 m and also form part of the Park.
The Sierra de Guara is a vast limestone massif, where we will discover its marine limestones —folded some 65 million years ago during the Alpine orogeny and shaped by karst processes—and, at its foot, gigantic accumulations of conglomerates upon which the characteristic mallos have been sculpted. Like a wall, the mallos defend the southern side of the mountain range as it transitions towards the Hoya de Huesca and the Somontano. Who has not been drawn to the chasms in the famous mallos of Salto de Roldán, San Martín de la Bal d’Onsera, Vadiello or the Puente de las Gargantas between Colungo and Asque?
The folds and fossils in the limestone, the karst landscape – with its fields of sinkholes, chasms, karst formations, caves and springs – and the conglomerate rock formations are all part of some of the Sites of Geological Interest listed by the Government of Aragon. To find out more, you can download the information sheets at http://www.boa.aragon.es/cgi-bin/EBOA/BRSCGI?CMD=VEROBJ&MLKOB=879288021515
Although, without a doubt, river erosion plays the leading role in this unique geological landscape. The rivers and ravines of Guara cut through the limestone and conglomerate formations as if a knife were slicing through a block of butter, carving out the deep canyons that have brought international fame to Guara and its spectacular canyoning routes. In the world of canyoning, very few people will not have heard of the following canyons:
- Flumen River: Palomeras, at the foot of the Salto de Roldán waterfall + its tributary from San Martín de la Bal d’Onsera.
- Guatizalema River: the Palomar Gorges, beneath the waters of the Vadiello reservoir, plus notable tributaries such as the Lazas, San Chinés and Isarre…
- River Formiga: the upper reaches and the extremely narrow Gorgonchón.
- River Alcanadre: Gorgas Negras, Barrasil and Las Peoneras, plus its main tributary, the Mascún, and its tributaries (Raisén, Otín, La Virgen…)
- River Isuala of Balcez: upper section, Dark and Narrow + tributaries (Alborzeral, Cautiecho…)
- Río Vero: its series of gorges stretching from Los Oscuros to Villacantal and the Fornocal tributary.
The water quality of the rivers in Guara, as well as that of the groundwater system which flows through the limestone and emerges from springs and seeps, is recorded in the inventory of Points of Fluvial Interesthttps://www.aragon.es/-/ puntos-fluviales-singulares which includes the Pillera ravine in Nocito, the River Alcanadre. (Tamara spring and straits), the Mascún river and spring, and the Vero between the Villacantal bridge and the Fuente ravine. The River Isuala de Balcez, from its source to its confluence with the River Alcanadre, is classified as a River Nature Reserve
Further information on the rock formations and landscapes of the Aragonese Pre-Pyrenees in general, and the Natural Park in particular, can be found at https://www.prepyr365.com/es/rutas/naturaleza/geologicas-y-paisajisticas.html
The flora and fauna of Guara. Uniqueness and environmental frontier
Guara is characterised by rugged and complex terrain. This, combined with its location at a climatic crossroads – the boundary between the cooler, wetter environments of the north and the drier, warmer ones of the south – has led to a marked difference between the northern and southern slopes of the mountain range. This phenomenon allows for the existence of a wide variety of flora and fauna, some of which are at the northernmost limit of their distribution in the Pyrenees.
Although most of Guara lies within a Mediterranean climate zone, 13.2% of its area features alpine, high-mountain environments, as can be seen on the range’s main peak and its north face, where specimens of black pine, beech forests and spruce forests in the southernmost part of the Pyrenees, as if it were a window onto Ordesa. The pine forests of black pine and Scots pine, in many cases established through 20th-century reforestation, were also naturally present in some of the mountain range’s shady areas, always accompanied by boxwood.
However, the most common forests in Guara are of Mediterranean origin, consisting of Spanish oaks and holm oaks or kermes oaks which, until the mid-19th century, covered much of its hills. Today, of those oaks, a few small woods and magnificent isolated specimens remain, such as those at San Úrbez de Nocito, Otín and Bagüeste. The holm oaks also suffered intense exploitation (felling, charcoal burning, clearing for farming, etc.), which led to the disappearance or thinning of large areas, replaced by kermes oaks, junipers and black junipers. Some monumental holm oaks have survived to the present day, such as the thousand-year-old holm oak of Lecina, listed in the Inventory of Remarkable Treeshttps://www.aragon.es/-/ arboles-y-arboledas-singulares, and chosen as the European Tree of the Year 2021. To find out more about these and other giant trees, you can also visit http://radiquero.com/arboles/
Sheltered amongst the holm oaks and kermes oaks of the southern foothills of the mountain range lies an unimaginable variety of plants, such as labiérnagos, durillos, cornicabras and madroños or alborzeras, shrubs that evoke the ancient tropical laurel forests that covered Guara millions of years ago. However, 50% of the Park’s area is covered by scrubland, particularly above the forest, on the ridges and highest hills exposed to the wind, including winter snows. This is the realm of the erizones, a spiny, cushion-like plant which, when it flowers in June, turns the Park yellow.
On the rocky cliffs of the mallos and canyons, one finds highly specialised plants, adapted to vertical terrain and extreme conditions, such as the king’s crown and the bear’s ear, as well as others found exclusively in the mountains, such as the beautiful Petropcoptis guarensis, which adorns the limestone walls of the Alcanadre and Vero canyons with its pink flowers in spring.
As for wildlife – ornithology and birdwatching have their own section on our website LINK – the Sierra de Guara provides a refuge for a wide variety of animals. Among the mammals, we can mention the wild boar and the increasingly abundant roe deer, which find refuge in the dense forests of the Park. The population of feral goats has experienced an unusual growth. There is also no shortage of the fox, the marten or beech marten, the wildcat, the weasel, the badger and, in the clean-water rivers, the otter. The cavities of caves and chasms also serve as a refuge for several species of bats that are under threat. Some place names remind us of the presence of large mammals in times long past: the Bal d’Onsera and the Ballón d’a Lupera bear witness to the fact that bears and wolves once inhabited the mountains.
The chub, the trout, the redfin a6> and the water snake are the main inhabitants of the rivers, along with the native crayfish, which is endangered – there is a Recovery Plan in place to boost its populations – not to mention the Pyrenean newt or guardafuens, a curious amphibian found exclusively in the Pyrenees, which is at the southern limit of its range here. Other damp areas are home to the common frog, common toad, natterjack toad and the extremely rare spotted tree frog and St Anthony’s frog, but also very rare reptiles, such as the Aesculapian snake, found in some of the park’s beech forests. To round off this brief list, we shall mention some highly valuable invertebrates that are vulnerable to habitat disturbance, specifically beetles such as the Rosalia alpina (beech forests) or the stag beetle and the great capricorn beetle (oak and holm oak forests), or the butterfly Erebia lefebvrei abosi, discovered in 2017 and found exclusively in Guara.
Further information on the geobotanical landscapes and botanical biodiversity of the Aragonese Pre-Pyrenees in general, and of the Natural Park in particular can be found at https://www.prepyr365.com/es/rutas/naturaleza/geobotanicas.html and at https://www.prepyr365.com/es/rutas/naturaleza/botanicas.html
