Regajal-Mar de Ontígola Reserve
The natural reserve of El Regajal-Mar de Ontígola is a natural area of the Community of Madrid (Spain), which has been protected since 1994, according to Decree 68 of June 30. It is located in the southern part of the region, within the municipality of Aranjuez, and has an area of 629.21 hectares, along which two main environmental units converge: the Mar de Ontígola wetland, a reservoir of Renaissance, today completely naturalized, and the adjacent land, among which the El Regajal estate stands out, a Mediterranean-subdesert mountain that is home to a great entomological diversity.
The first unit mentioned brings together important communities of marsh vegetation, which provide shelter, temporarily or permanently, to numerous waterfowl. The second, for its part, constitutes one of the most important butterfly reserves on the planet, with species such as Plebeyus pylaon, Iolana iolas and Zerynthia rumina. In 1979 entomologists belonging to the International Union for Conservation of Nature cataloged El Regajal as the fifth world priority in the conservation of lepidoptera.
In addition to its natural wealth, the reserve shows important historical, cultural and architectural values, the result of its close relationship with the Royal Site of Aranjuez, to which the Mar de Ontígola supplied water from the 16th century to the middle of the 16th century. XX. Its dam, in which architects such as Juan Bautista de Toledo (1515-1567) and Juan de Herrera (1530-1597) participated, marked a milestone in the history of modern hydraulic engineering.
Legislative framework
The El Regajal-Mar de Ontígola Nature Reserve was established as such by Decree 68/1994 of June 30, of the Community of Madrid. This standard also defined the Natural Resources Management Plan, which, however, was reviewed and modified eight years later, according to Decree 143/2002 of August 1.
In addition to this legal figure, there are others that reinforce the levels of protection assigned. The area is included within the Special Conservation Zone (ZEC) of Las Vegas, slopes and páramos in the southeast of Madrid, which, in turn, is listed as a Site of Community Interest (SCI) and attached to the Natura 2000 Network of the European Union. Due to the importance of its birdlife, it is part of the Special Protection Zone for Birds (ZEPA) of Los Carrizales y Sotos de Aranjuez.
Other reference standards are Law 7/1990, of June 28, on the Protection of Reservoirs and Wet Areas of the Community of Madrid; the Catalog of Reservoirs and Wetlands, also approved in 1991 by the Community of Madrid; and, already at the state level, Royal Decree 1193/1998, which transposes Directive 92/43 of the European Union, regarding the conservation of natural habitats and wild fauna and flora (modified, in turn, by Directive 97/62).
Most of the reserve is privately owned, although the regional administration has granted the use of some plots, the case of the one occupied by the butterfly farm built in 2002 by the Department of the Environment of the Community of Madrid, within the El Regajal estate. The only area that is publicly owned is the Mar de Ontígola, which belongs to the National Heritage, the body on which the possessions that were in the hands of the Spanish Crown depend. Despite this, its management is the responsibility of the aforementioned council.
Limits
With an area of almost 630 hectares, the El Regajal-Mar de Ontígola Nature Reserve accounts for 3.1% of the municipality of Aranjuez, made up of a total of &&&&&&&&&&020111.&&&&&020,111 hectares. Its northern limit is defined, in its central part, by the urban nucleus itself and, on the sides, by wild areas. The eastern and southern borders are marked by the dividing line with the province of Toledo, through the municipality of Ontígola, while the western one is drawn by the Las Salinas stream.
The reserve is crossed by four major communication routes: the N-IV highway, the A-4 highway, the R-4 highway and the Madrid-Levante high-speed railway line, which crosses the estate of El Regajal through a tunnel of &&&&&&&&&&&02080.&&&& &02080 meters long, built in 2008.
Sea of Ontigola
Toponymy
The place name comes from the Toledo town of Ontígola, from which the reservoir is less than three kilometers away. With this name is also known the stream that, coming from the aforementioned municipality, supplies water to the lagoon. The word sea refers to its dimensions, notably larger than those of other wetlands in the area.
History
The origins of the Mar de Ontígola go back to 1552, when Felipe II (1527-1598), while still a prince, signed an instruction in which he urged Diego López de Medrano, governor of the administration of the territory of Aranjuez, to make "a very large lagoon in the Ontígola stream, and another two or three small ones in the one towards Ciruelos, so that birds of arrogance can come to them".
The works began at the end of 1560 under the direction of Juan Bautista de Toledo (1515-1567) and the masters Juan de Castro and Francisco Sánchez took part in them, as well as the plumbers Adrian van der Müller and Pierre Jasen, who the King called from the Netherlands to work in the ponds of the Casa de Campo in Madrid. After the first cracks appeared in 1565, followed by others in 1568, Juan de Herrera (1530-1597) and Jerónimo Gili completed the project in 1572.
Although the reservoir was designed to irrigate different orchards and gardens, it also developed a recreational function, mainly in the 17th and 18th centuries. Recreational navigation was practiced there and tournaments, parties and games were held, such as the one on the cliffs. This consisted of hunting animals, preferably fighting bulls, which were thrown into the lagoon from precipices prepared for this purpose, to, once in the water, kill them by means of different procedures.
In 1625, Felipe IV (1605-1665) commissioned the architect Juan Gómez de Mora (1586-1648) to build an artificial island, in which a gazebo, a jetty and a firing point were set up. Seventy years later, in 1695, a light masonry bullring was built in the vicinity of Mar de Ontígola.
In the 18th century various hydraulic infrastructures were built, aimed at optimizing the flow of the pond. In 1734 the so-called Mar Chico was created, a settling pond linked to the Sea of Ontígola, from which a water pipe started to the island's garden; and during the reign of Carlos IV (1748-1819) a new ditch was made that reached the Prince's garden. Throughout the 19th century the reservoir was cleaned several times, due to the clogging it suffered.
Physical environment and natural values
The Ontígola Sea is nestled in the northwestern corner of the park. It has an approximate extension of about 3'8 Ha, mostly occupied by hydrophilic vegetation. If the vegetal biomasses are not taken into account, the aquatic surface decreases to 7 km², with permanent water. The reservoir was built in a small valley, where rafts of water were produced naturally. It feeds on the runoff from the surrounding gypsum hills and the Ontígola stream, a tributary of the Tagus River, which it flows to the left, which in this section is also known as Yesares, due to the type of material with whom he comes into contact. This small river course has a route of 16 kilometers and throws an average of 1.8 hm³ of water into the reservoir.
In its flat part, the Mar de Ontígola accumulates colluvial clays and silts, coming from the erosion of the slopes that surround the sheet of water. The erosive processes are especially intense, with values that reach 125 tons per square kilometer, due to the brittleness of the materials that make up the hills, their high slopes, and the sparse vegetation developed there. All of this has caused a notable decrease in the storage capacity of the reservoir, currently limited to 0.2 hm³, half of what was recorded in certain historical records.
The reservoir is home to important marsh vegetation, which, as sedimentation progresses and the sheet of water is cut, colonizes the land. Although they are mostly reed beds, the shores are also populated by tamarisk, both Tamarix canariensis and Tamarix parviflora; sedges of Scirpus and Juncus acutus; and cattails. Due to its temporary waterlogging, grasslands of therophytes, such as grasses and legumes, also develop on the edges.
Within this vegetation inhabit small invertebrates, fish, reptiles, amphibians, small mammals, and birds. Especially relevant is the birdlife, made up of ducks such as the mallard, the great crested grebe, the shoveler, the common pochard or the tufted pochard, as well as other species such as the gray heron, the stork, the common coot, the marsh harrier, the bittern, the martinete or the little bittern. More than a hundred bird species have been recorded, close to 70% of them protected, with concentrations that, at certain times, reach a thousand individuals.
Architecture
The Sea of Ontígola is retained by a dam of Renaissance origin that measures 150 meters long and six meters high. Said dam is made up of two walls filled with earth, which jointly reach a thickness of ten meters, and has five buttresses on its external face, each with a length of 3.3 meters and a width of 2.75, to those that are added others in the interior, not visible when being covered by the waters. The dam is considered a milestone in the history of hydraulic engineering, not only because it defined the model that later modern buttress dams followed, both in Europe and America, but also because it was one of the first to be built with an embankment..
The Mar de Ontígola is on the Red List of endangered heritage, drawn up by the Hispania Nostra association, due to its poor state of conservation. Regarding the dam, both the retaining wall and the spillways are covered with earth and brush, which causes the water to overflow from the crest, with the consequent degradation of the structure. Likewise, the accumulation of mud and the proliferation of invasive plants, mainly reeds, has caused a notable decrease in the storage capacity of the reservoir.
El Regajal
Toponymy
The place name of El Regajal alludes to the abundance of regajos (puddles that form from a stream) in the area and which gave rise to a first channeling in the 15th century, completed in the following century with the construction of the Ontigola Sea. Currently this name is applied to the private estate located to the west of the reservoir, which in one part is dedicated to viticulture and which in another maintains wild areas of great botanical and zoological interest. In a broader sense, it is used to refer to the lands that extend to the south of the urban center of Aranjuez, where, in addition to the aforementioned farm, there are urbanized spaces, which, like the Gonzalo Chacón Industrial Estate, are outside of the the reserve.
History
The first chronicles in which El Regajal appears date from the end of the 15th century and refer to the construction of a canal in the Ontígola hollow, where the homonymous reservoir currently stands, intended to collect the excess water that was collected there. they accumulated. This infrastructure was carried out in the times of the Catholic Monarchs and was promoted by Gonzalo Chacón, mayor of the Dehesas de Aranjuez.
Apart from its water resources, El Regajal has been the subject of research by numerous naturalists, who came to Aranjuez attracted by its natural values. Although the first scientific visits date back to the 18th century, it was from the 19th century, coinciding with the development of modern entomology, when they became recurrent. During the reign of Ferdinand VII (1784-1833), Juan Mieg, director of the Royal Cabinet of Natural History, visited the site and, later, Mariano de la Paz Graells and Laureano Pérez Arcas, who reported on the diversity of insects in the area in the work Unpublished Dietary (1848).
The inauguration of the railway between Madrid and Aranjuez in 1854 facilitated the arrival of European entomologists, such as Jorge Lauffer, Maximilian Korb and Otto Staudinger, who joined the Spanish Ignacio Bolívar y Urrutia, Ricardo García Mercet, José María Dusmet Alonso and Fernando Martinez de la Escalera. In the 20th century, Wernen Marten, Juan Torres Sala, Gonzalo Ceballos, Antonio Varea de Luque, Ramón Agenjo Cecilia, Joaquín Templado, L. G. Higgins, W. B. L. Manley, Fidel Fernández Rubio and Miguel Gómez Bustillo were added, the latter considered one of the most active figures in the face of preserving the natural wealth of El Regajal.
Physical environment and natural values
The El Regajal farm has an approximate area of 570 hectares, which represents 90.5% of all the protected space. It is made up of a succession of hills, through which various valleys are formed, furrowed by the Colmenar, Cantarranas and Salinas streams, all of which are tributaries of the Tagus River on its left bank. The last mentioned fluvial course marks the western limit of the reserve, which it crosses over two kilometres, of the seven that make up its route.
The lithological conditions of the place define a high degree of specialization of the existing vegetation:
- In the plaster hills the low mountain extends, with arbusive masses of coscoja, which represent two thirds of the plant surface of the entire park. This species has replaced the dense oak, which is in regression in much of the central area of the Iberian peninsula. Next to the coscojars, they open their way to retamares Scorpius people and Retama sphaerocarpa, tomilars and different communities of black thorn.
- The warmer soils are populated with spice, sage and rosemary, while in the most insolate the spartals of Lygeum spartum and Ephedra fragilis.
- Areas made up of margoyesmal materials, especially abundant in the soft slopes, show a low development of the soil and a high aridity, which limits the vegetation to very determined species, such as gypsies, be they atochares, gamones, classroom retamas, syrups, boars or artemises.
- In the vicinity of the stream of the Salinas there appears the shroud thorn, while species of endemic character grow, like the Sedum gypsicola, the Sisymbrium cavanillesianum, the Frankenia thymifolia, the Frankenia polished or Limonium dichotomum.
The farm brings together a fauna characteristic of Mediterranean-subdesert mountains, with species such as hare, rabbit, wild boar, tawny owl, partridge or blackbird. However, its main faunal interest lies in its populations of lepidoptera, for which it has been internationally recognized as one of the most important butterfly reserves on the planet.
The confluence in the area of different ecotones (grasslands, cultivated areas, cliffs, scrub...) favors the presence of numerous varieties of butterflies, whether they are wintering (they spend the winter in El Regajal in a chrysalis state), migratory (who stop at the place during their displacements) or stable permanence. There are about 600 species, 80 of which are daytime butterflies, which represents 35% of those existing in the Iberian Peninsula in reference to the aforementioned superfamily.
Many of them, such as the Plebejus hespericus, the Iolana iolas and the Coscinia romeiiy, appear in the Regional Catalog of Threatened Species of the Community of Madrid. Others are local endemics, with an adaptive development that lowers the average size of the species, to the point of constituting minimal subspecies. This is the case of the Zerynthia rumina or harlequin butterfly, which, with a wingspan of about sixteen centimeters, is considered to be the largest lepidopteran in Europe and which in Aranjuez has much smaller dimensions. Euchloe tagis, Pseudophilotes abencerrajus, Gegenes nostrodamus and Libythea celtis.
Other areas
In addition to Mar de Ontígola and El Regajal, there are other natural spaces within the reserve, such as Paraje de los Cotillos, which is located to the east of the reservoir. It is a set of slopes formed by margolime materials, with deposits of boulders and sporadically some very hard gypsum outcrop, at the bottom of ravines. Its predominant vegetation is kermes oak, which occurs mainly in shady areas, and atochar, present on steeper slopes, where the soil is less developed.
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