Almost five years ago, just after leaving quarantine, Antonio Martín Higueras and the Iberozoa association team began monitoring the amphibians of Tres Cantos. They wanted to study how the urbanization of the Parque Norte area was affecting the population of these species. “That was an open-air laboratory in which you could see, almost live, how amphibians react to the loss of habitat. It is a pioneering study in Spain and probably in Europe, in which we have done population monitoring and we know how many amphibians there were and at what time. We have identified individuals from 40 ponds And the interesting thing is that, thanks to monitoring, we have been able to find out many details of the hidden life of amphibians: how long they live or how they move,” Muñoz details.
From their research they have extracted data that they consider valuable to take into account when considering new developments. For example, that the natterjack toad is capable of traveling up to a mile and a half and crossing up to seven roads to look for another pond to live in when its own runs out of water, or that up to 80% of the amphibians in the area have been lost in the last five years. They have mainly focused on three species: the natterjack toad, the most abundant and perhaps best known because it is the typical toad heard at night near cities; the spadefoot toad, “which is more threatened and a little more difficult to see; and the gallipato. We have chosen these three species because they are the most abundant in this area and because they represent very well the populations of the temporary ponds of the Mediterranean ecosystem. As for that 80%, we must clarify: of the gallipate and the spadefoot toad, two species that move little and remain within their ponds, between 90 and 95% of the populations have been lost. The surprise came from the natterjack toads,” he says.
And how have they followed up? TO through a “DNI”, a visual document with which they have identified each individual by their spots and other distinctive features. Every night during these years, the team has gone to a pond, captured the amphibians for a few minutes, weighed them, measured them and photographed them. Later, with these images they have created a “DNI” or visual document that has allowed them to recognize each individual. All of this work has been carried out accompanied by the local population because, in addition to science, the association wanted to disseminate information. Even today, and during the most favorable months, they organize excursions to observe some of the species that live in the town. On these routes you can see, yes, in the cold and at night, newts, natterjack toads, San Antonio frogs and gallipates, one of the species “that is most liked and surprising because it has a very curious defense mechanism: when it feels threatened, it sticks out its ribs and the predators, when punctured, flee. Afterwards it is able to put them back and regenerate. And the best thing is that you can see them literally next to the house,” explains Muñoz.
The participants, while learning to identify species and get to know these animals better, also help to do citizen science. Furthermore, based on the observations, the team has been carrying out conservation work in some of the ponds around the Bodonal stream. “At first, we obtained funding from the Community of Madrid and the Tres Cantos City Council and we began to restore ponds, apply conservation measures and organize informative night routes. Only six original ponds remain, but we have restored three others and built one more that will remain within the parks and outside the urbanizable area. We prioritize the restoration of existing ponds because they are well located and, little by little, we want to generate ecological corridors connected to the streams that these animals use as highways. It is not necessary to do more account ponds; it is enough to associate them with these streams to connect the entire peripheral area of the municipality.”
The Iberozoa association was born almost at the same time as the amphibian project and, in the few years it has been in existence, it has managed to open 11 branches and hire eight people. “We really like this project because it is a perfect example of how we want everything we develop to be, since it creates job opportunities in science, which is one of our objectives. Furthermore, we believe that The potential and value of Tres Cantos is not only in conserving these species here, but in becoming a reference so that, in new urban plans of any other town in Spain, amphibian populations are taken into account and compensatory measures are put in place, such as plans to restore ponds.. Temporary ponds last a few months, but they are ecologically very important and fundamental for biodiversity,” concludes Muñoz.
in descent
A work published in 2025 in the magazine Landscape Ecologyin which researchers from the National Museum of Natural Sciences (MNCN-CSIC), the Autonomous University of Madrid, the Spanish Herpetological Association and the Center for Research in Biodiversity and Genetic Resources collaborated, shows that the lack of connection between populations is one of the most serious problems faced by the 16 native species of amphibians that inhabit the Community of Madrid.
The work, which updates the population distribution atlas carried out 20 years ago, has identified the landscape elements that constitute ecological barriers for amphibians and hinder the exchange of individuals between populations: high mountain areas, urbanized areas and large rivers and reservoirs. On the contrary, the elements that favor the connection between populations are the riverside vegetation along the valleys of some rivers or the peri-urban green areas, which function as ecological corridors. “There are species, such as the common midwife toad, the San Antonio frog or the Iberian newt, that show strong population fragmentation, which requires the urgent implementation of conservation measures. Amphibians are part of our cultural and biological heritage and many of them are endemic to the Iberian Peninsula,” the study noted.