With an area of almost 630 hectares, the El Regajal-Mar de Ontígola Nature Reserve (Reserva del Regajal-Mar de Ontígola) habitat brings together a characteristic fauna of the Mediterranean-sub-desert mountains, with species such as hare, rabbit, wild boar, tawny owl, partridge and blackbird being very common. The gypsum hills with endemic flora species and unique vegetation and are populated with species such as kermes oak and rosemary are well preserved.
The Natural Reserve of El Regajal-Mar de Ontígola is one of the most unknown natural spaces in the Community of Madrid, despite having a great wealth of fauna . This is due to the fact that most of its 630 hectares are on private farms. (The one of El Regajal stands out, which has its own vineyards and winery attached to the designation of origin of Vinos de Madrid.)
However, the main wildlife interest here lies in its butterfly populations for which it has been internationally recognized as one of the most important butterfly reserves in Spain. Over 100 of the 230 odd species of lepidoptera of Spain have been recorded here which is interesting not only for their number but also for the rarity of some of them. In 1979 entomologists from the International Union for Conservation of Nature (IUCN) ranked El Regajal as the fifth world priority in conservation due to the importance of its butterflies.
The site is included within the Special Conservation Zone (ZEC) of Las Vegas, slopes and moors of 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 avifauna, it is also part of the Special Protection Area for Birds (ZEPA) of the Carrizales and Sotos de Aranjuez.
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Booking.comAn interesting history.
The origins of the Sea of 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 build “a very large lagoon in the Ontígola stream, and another two or three small ones in the one towards Ciruelos in order to atract birdlife“. (Presumably ducks for eating?)
The works began at the end of 1560 under the direction of Juan Bautista de Toledo (1515-1567) and the master builders Juan de Castro and Francisco Sánchez participated as well as the Dutch dyke experts Adrian van der Müller and Pierre Jasen. The project was completed in 1572.
Although the reservoir was conceived for the irrigation of different orchards and gardens, it also developed a rather gruesome recreational reputation whereby in the 17th and 18th centuries sailing was practiced and tournaments, parties and games were held. One particular “game” consisted of hunting animals, preferably fighting bulls, which were thrown into the lagoon from the cliffs and once in the water killed in the most dramatic way possible..
In 1625, Felipe IV (1605-1665) commissioned the architect Juan Gómez de Mora (1586-1648) to build an artificial island, on which a gazebo, a jetty and a firing point were set up. Seventy years later, in 1695, a small bullring was also built in the vicinity of Mar de Ontígola
In the 18th century, various hydraulic infrastructures were built, aimed at optimizing the flow of the reservoir. In 1734 the so-called Mar Chico was created, a settling pond linked to the Mar de Ontígola, from which a water conduit came to the island’s garden and during the reign of Carlos IV (1748-1819) a new canal was made that reached the garden of the Prince.
The Regajal-Mar de Ontígola is on the Red List of Heritage in Danger due to its poor state of conservation. Regarding the dam, both the retaining wall and the spillways are covered with earth and weeds, which causes the water to overflow from the crown, with the consequent degradation of the structure. Likewise, the accumulation of sludge and the proliferation of invasive plants, mainly reeds , has caused a notable decrease in the storage capacity of the reservoir.
Of course the dilemma is clean and repair or just let nature have its way. Time will tell.
Current threats and future
This enclave so privileged from the point of view of biodiversity, whose conservation depends on the Community of Madrid, is, however, threatened. So much so that in the last 25 years up to seven species of diurnal butterflies have disappeared , according to studies by the three researchers José González Granados, Carlos Gómez de Aizopurúa and José Luis Viejo Montesinos, who have been studying the wildlife here for many years.
In 2001 these naturalists embarked on a project, together with the Community of Madrid, which consisted in the creation of a butterfly farm for the breeding and study of autochthonous species but In 2011 the project failed and what was once the largest butterfly farm in Spain has been closed. In 2013, the Aranjuez City Council requested a grant from the European Life program to be able reopen but as of 2021 still no sign of it reopening…….
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