Portal de Turismo de Castilla y León

We welcome you to the Riaza River Gorge Park House.

As in the rest of the houses of the park spread throughout the Castilla y León region, it is the recommended gateway to these natural areas. At this interpretation centre, our staff will inform you about the Nature Reserve and help you plan your visit.

Here, information on emblematic species and habitats is provided to facilitate the identification and highlight the cultural and natural heritage of these places, respectfully, while promoting the conservation and appreciation of biodiversity and cultural heritage.

This house is located in the town of Montejo de la Vega de la Serrezuela, in the northeastern part of the province of Segovia, bordering Burgos and Soria.

The building was completed in 2002, and the permanent exhibition opened in 2004. In addition to the exhibition, environmental education activities are carried out with school groups and environmental volunteers. The Park House has several thematic areas that form part of a permanent exhibition, including an audio-visual presentation on the natural resources of the Nature Park.

You can also find a summary of the panel texts in English, French, and in Braille in Spanish.

A few metres before the entrance, a large information panel welcomes you with information about the Riaza River Gorge Nature Park.

The Park, located in the north-east of the province of Segovia near the border with Burgos, stretches along the Riaza River, which divides the area into three distinct areas. The first, between Maderuelo and the Linares del Arroyo dam, has a gentle relief since the river has been dammed since 1951. Then, between the dam and the stream of El Casuar, the river forms a limestone canyon up to 150 metres deep. Finally, from the stream to Montejo de la Vega, the river creates an asymmetrical valley with a fertile plain. The vegetation on the moor is predominantly steppe-like, with patches of woodland adapted to the continental climate. The limestone cliffs, favourable for rocky birds, and the Linares del Arroyo reservoir, which is a key wintering area for waterfowl, stand out.

Enter the Park House now.

You will reach a hall where you will find the green shop where you can buy typical local products and souvenirs of your visit.

Opposite the entrance, to the right of the green shop, a door opens into a room with temporary exhibitions and where workshops, meetings, and other cultural activities take place.

Back in the lobby, there are shelves with magazines and brochures with information on the park.

Carry on and cross over to the visitor service desk, where the park monitors will help you plan your visit.

At the back of this reception area, there is a room to the right where the toilets are located.

To the left of the counter, a curtain with images of the river’s gorges leads to the permanent exhibition.

The first panel on your left tells you about the karstic process that has formed the gorges of the Riaza River.

During the Cretaceous period, this region was submerged under the sea, where calcareous sediments were accumulated and compacted. Later, the sea retreated, exposing these limestone rocks, which were uplifted by the Alpine Orogeny through folds and faults. In the later Quaternary stage, the incision of the fluvial network occurred. The erosive action of the water of the Riaza River over millions of years has shaped this unique canyon. In addition, karstic phenomena have been generated, giving rise to various hollows and caves. A karst is produced by the indirect dissolution of calcium carbonate from limestone rocks due to the action of slightly acidic water. Surface and underground waters dissolve the rock and create galleries and caves, which, by partial subsidence, form sinkholes and even canyons.

Under the panel, use the binoculars to discover what is on the other side.

Below, on a small pedestal less than a metre high, two rocks are displayed.

The following panels on the left highlight the diversity of ecosystems, which include healthy and dense holm oak groves, savin groves in the process of regeneration, well-preserved riparian forests with trees such as willows, ashes, and poplars, and extensive moorlands with abundant small vegetation, especially aromatic plants.

The panels also mention rocky walls where rupicolous species, areas of cultivation, both rainfed and irrigated crops predominate, and finally, a wetland area that includes the Linares reservoir and the course of the Riaza River. These rupicolous species are those that grow or live on practically bare rocks, on cliffs and steep slopes, with poorly developed soil.

The rich diversity found in the park’s moorlands, both in flora and fauna, goes unnoticed due to the uniformity of the landscape. In this context, the adaptations of the organisms that inhabit the area focus on mimicry, in the case of the fauna, and on small sizes for the flora. These adaptations are the result of poorly developed, poor soils of calcareous origin and adverse climatic conditions such as strong winds, high temperatures in summer and frosts in winter.

In this ecosystem, rainfed cereal crops are of considerable socio-economic importance. As for the fauna, there are birds such as the red-legged partridge, the lark, the crested lark, and the stone-curlew, as well as mammals such as the rabbit, the hare, and the fox.

The flora is mostly composed of shrubs such as genista scorpius, and also includes aromatic plants such as thyme, lavender, and sage.

Throughout the area, there are also woodland areas.

These ecosystems are found within the canyon and are mostly composed of evergreen vegetation, mainly junipers and holm oaks. To a lesser extent, there are also deciduous Portuguese oaks.

The Spanish juniper shows a remarkable ability to survive in impoverished soils, with low rainfall and significant temperature variations. It is slow-growing and long-lived, tending to form open woodland and open spaces.

Although holm oaks and Portuguese oaks share the same family, they have some significant differences. The holm oak has hard leaves that remain through the winter, covering the sunny slopes with a dark green. On the other hand, the Portuguese oak, with shinier leaves that fall off in winter, is more demanding in terms of humidity and is found on some shady slopes.

There is a fauna linked to this type of vegetation, made up of large mammals such as wild boar, roe deer, and wild cats. Smaller mammals such as weasels and martens also find refuge here. In terms of birds, the presence of the golden eagle is particularly remarkable.

The diversity of ecosystems in this place contributes to the fact that the fauna is extremely varied, with birds, particularly birds of prey, standing out. The griffon vulture is the most emblematic species, forming the largest colony in Europe and possibly the world. The habitat is also shared by Egyptian vultures, golden eagles, hawks, and eagle owls, among others. Among the mammals, roe deer and wild boar stand out, as well as otters.

As for reptiles, there are snakes such as the ladder snake, the Montpellier snake and the viper, and amphibians such as the midwife toad and the natterjack toad. Fish, mainly barbel and trout, can also be observed.

Under these panels, there is a bench on which you can rest. In front of the bench, you will find a scale model of the Nature Park illustrating the differences between the reservoir and the river areas, including walls and canyons. The panels provide details on the characteristics of the various ecosystems found in the Park.

Further on, you’ll find a model of the moorland terrain, with rocky ground and a few small plants.

Next to it, there is a small wall with three panels with drawings of the fauna that inhabits the banks, the cliff, and the forest.

Go around this small wall and continue along the left wall.

You will come to the corner of the wall. On the first panel, perpendicular to the left wall, there are panels with old images of the people of the towns that make up the Riaza River Gorge Nature Park: Maderuelo, Montejo de la Vega de la Serrezuela, and Valdevacas de Montejo.

From the 11th century onwards, Maderuelo became a Comunidad de Villa y Tierra, a sort of county, on which several villages depended legally and administratively. With a population of 150 inhabitants, it preserves its mediaeval walls and gates in good condition, which nowadays stand over the Linares del Arroyo reservoir. The ancient Roman bridge becomes visible when the water level of the reservoir decreases. The two Romanesque churches within the walled complex and the monumental complex of the village, with its houses and coats of arms, are outstanding features.

Like Maderuelo, Montejo also had the status of Comunidad de Villa y Tierra. Remnants of fortifications have been preserved. In terms of traditional architecture, the houses with stone façades, wine cellars, and an old flour mill that ground flour during the day and supplied electricity to the nearby villages at night are especially remarkable. The current population is estimated at around 200 inhabitants.

Finally, Valdevacas de Montejo, located high up on the moor, keeps the old washing place and the pigeon lofts, which were key to the family economy, in perfect condition. Its current population is around 30 inhabitants. The economic base is still agriculture and livestock farming, and as it is part of the Ribera del Duero Denomination of Origin, vineyards are cultivated. The Nature Park should also help consolidate the growing trend in tourism, a sector that could become significant for the area.

To the right of these panels, a large panel with black and white images provides information about Linares del Arroyo, the village that was submerged when the reservoir was built. In 1951, after the construction of the dam and the expropriation of the land belonging to the village of Linares del Arroyo, the inhabitants were relocated to the municipality of La Vid in Burgos. Today, the ruins of Linares lie beneath the waters of the reservoir, emerging only during periods of intense drought.

Then, on the next wall, there is a sign dedicated to Hoticiano, who was one of the longest-serving guards at the Montejo de la Vega raptor refuge.

Next to this panel, there is yet another panel dedicated to Fidel José Fernández y Fernández de Arroyo, a naturalist who was passionate about the Riaza River gorges and was in charge of the censuses. He carried out numerous studies on the fauna of the Montejo bird of prey refuge and compiled information on the fauna observations made in the area.

To the right of this panel, there is an exact replica of a griffon vulture on some rocks.

The griffon vulture is a large bird of prey, weighing between 8 and 10 kilos, with a wingspan of over 2.5 metres. Its plumage is predominantly ochre-brown. Its relatively small head is covered with white feathers and has bare, wrinkled facial skin of a yellow or pinkish hue. With large, dark eyes, the griffon vulture has a strong, curved beak adapted to tear flesh from carcases. Its stout legs end in sharp claws, while the tail is short and square. In flight, it has broad, flat wings, taking advantage of thermal currents to glide long distances in search of carrion.

This species boasts one of the largest colonies in Europe, with over 700 pairs counted in 2023.

Its reproductive cycle is exceptionally long. A single egg is laid between December and January, and after 54 days of incubation, the chick hatches and remains in its parents’ care for the next four months, at which point it leaves the nest.

Next to the vulture, there is a wall to create a semi-enclosed space.

On the right wall, several vertical panels are displayed with photographs and information on the chronography of the history of the park and the territory.

In 1974, Montejo de la Vega became the first place in Spain to sign a land stewardship agreement, marking the beginning of its history as a Nature Park.

At that time, the area comprised two wildlife refuges: one of 315 hectares, managed by the Confederación Hidrográfica del Duero, and another of 2100 hectares, managed by WWF/ADENA.

The Montejo de la Vega raptor refuge, inaugurated in 1975, was declared in 1974 with the collaboration of Adena and Félix Rodríguez de la Fuente, who was vice-president of Adena then. The park’s history began three decades before its official designation, with the first land stewardship agreement with the town of Montejo, in which hunting rights to protect the birds of prey nesting there were granted. A rubbish tip was established for the vultures, and Hoticiano was hired as a guard until his retirement, which is when his son Jesús took over his post.

In 1987, the park was included in the catalogue of Important Bird Areas and designated as a ZEPA (Special Protection Area for Birds) in the same year. The area was further expanded in 2000. In 1991, it was included in the inventory of areas of potential interest for the Natura 2000 Network and formed part of the Network of Natural Spaces of Castilla y León, as well as in the Plan for Protected Natural Spaces, with the aim of being declared a Nature Park.

In 1999, the Spanish Government proposed it as a Site of Community Interest. Finally, on 21 December 2004, the Castilla y León Regional Government declared the Riaza River Gorge Nature a Nature Park, noted for its geomorphological and botanical singularity and the rich community of rupicolous birds it shelters.

In the centre of this space, there is a pedestal with a lever that allows you to control a real-time video camera placed on a griffon vulture’s nest.

Behind the curved wall with posters, drawings of other birds that populate this area are displayed.

Then, on the next wall, as you turn the corner, you will find a shelf made out of a wooden pallet on which there are different jars with aromatic plants that can be found throughout the park.

Following the wall, there are panels on the aquatic ecosystems of the Riaza River.

Riverside trees are characterised by being deciduous and relatively fast-growing, providing stability to river banks and shelter to a variety of birds and other animals. Among the most common tree species in this area are the willow, with elongated, deep green leaves; the poplar, which stands out for its heart-shaped leaves and great height; and the ash, whose compound leaves and wind-dispersed seeds at the end of the summer distinguishing this tree from others. Alongside these trees, there are smaller shrubs such as hawthorn, wild rose, and blackberry. In isolated areas of the river, yellow water lily, and wild iris can be seen, adding colour to the environment.

The animal species associated with this ecosystem include the trout, which requires clean, cold, and oxygenated waters, and the otter, which is the characteristic mammal of the Riaza River. Otters are also a biological indicator of water quality as are signal crayfish, introduced in the 1970s and present in most Spanish rivers.

On the left wall, there is a glass case with an image of the gorges of the Riaza River in the background.

The fossils in the display case tell the story of the formation of the rock, the sedimentation of the early seas and the evidence that has survived to the present day.

Above is an image of the cortado, an ecosystem composed of vertical limestone walls with numerous hollows formed by the dissolution of water.

Limestone rock, a sedimentary rock mainly composed of calcium carbonate, exhibits a greyish-orange hue due to impurities such as clays or oxides. Due to its marine origin, it is rich in fossils.

Although it appears to be devoid of vegetation, in reality, a diversity of plants inhabit this environment, known as rupicolous plants. These plants have adapted to the scarce soil available on ledges and crevices and have developed strategies to secure water, growing only during favourable periods and remaining in the form of bulbs or rhizomes during the rest of the year. These include lady’s purses, navelworts, and jasonia glutinosa.

Now you will find a wooden lectern with a signature book that leads to the last panel, which talks about the invertebrates and insects that inhabit the river, such as the signal crab and the dragonfly.

Crayfish and dragonflies play crucial roles in river ecosystems, contributing to the health and balance of rivers. As indicators of water quality, crayfish are sensitive to changes in pollution and sedimentation, providing early signals of potential environmental issues. In addition, their digging and feeding activity helps maintain the health of the riverbed by aerating the substrate and facilitating the growth of other aquatic species. On the other hand, dragonflies, in their aquatic larval stage, are efficient predators, controlling populations of mosquitoes and other insects. As adults, they play a vital role in pollination and are sensitive indicators of water quality and the surrounding habitat.

On the left-hand side, a curtain leads back to the reception area. Take the door on your left.

You will come to a small space, with a door on the left wall, which grants access to the audio-visual room, where a 15-minute video about the daily life in the area, the fauna and the flora is projected.

Once the video is over, leave the audio-visual room and go through the door on your left, which will lead you to the garden.

Once you exit, you will come to a small brick platform. A dirt path to your left leads to the car park, from where you can enter the garden directly, without having to go through the Park House, as the garden is open to the public.

You will come to a sign with a map of the garden. This has been conceived as a short botanical tour in which different tree species are featured, some of which have informative signs describing them.

The path will lead you to a section with panels dedicated to the butterflies present in the Park.

If you pay attention along the route, you will hear the murmur of the Riaza River as it passes near the garden and the birds that live in these trees.

Following the sandy path, you will pass a stone and concrete path leading directly to the river and is not protected by a fence. You will also pass in front of wooden benches where you can sit and relax, and take in the fresh air of the park. After that, you will come up to the butterfly signs and, at the end of the path, you will reach a children’s playground with some swings and a picnic area.

On the left-hand side, before the picnic areas, there is an accessible path formed by a 1-kilometre-long wooden footbridge, which leads to Fuente de la Pisadera. It is a flat path, which passes next to a rock wall where there are several vultures’ nests.

With this audio track, the visit to the Riaza River Gorge Park House comes to an end, where the rich flora and fauna, the karstic landscape, marked by the presence of vultures and the life around the Riaza River are highlighted.

If you would like more details, you are welcome to come to the reception desk or speak to any of the collaborators at the Park House.

Thank you for your visit.