The Ribera del Ebro as it passes through Zaragoza is filling with nibbled trees. Tens. Dozens of tens. It has been confirmed by the City Council itself, which has counted around 70 damaged specimens in different parts of the urban section of the river. Actually the phenomenon has little mysterious and there are less doubts about who is responsible. What is not so clear is how to avoid it. In Spring Environment he already launched a plan to protect his poplars and poplars, which has not avoided that he has to withdraw one.
The key is in a particularly voracious rodent.
What happened? That Zaragoza has encountered dozens and dozens of nibbled trees. Literally. The technicians of the Aragonese City Council have identified neither more nor less than with 70 trees with marks of dentelladas in several sections of the Ebro riverbank as it passes through the city. One of them, a black poplar (Populus nigra) Located in the parking lot, it is so deteriorated that the Consistory has come to the conclusion that he has no choice but to withdraw it.
Is it so serious? Not all trees are equal to damaged, but in the specific case of the Park of the Eyes, municipal technicians have concluded that there is a “collapse risk”. “Being in an area of playful use is a considerable risk for citizens,” Apostille The City Council. And as an image always says more than a thousand words has shared a photo in which it can be seen how the trunk is stripped of bark and shows a crescent -shaped gap on the side. Around it, the floor is full of splinters.
Who is responsible? The Zaragozano Consistory has few doubts about it: The beavers. Moreover, its presence in the area and the damage they cause to trees are no novelty for technicians, who have been trying to protect the trees from the most punished parks for these large rodents.
In March, the Ministry of Environment, hand in hand with the conservation unit of the natural environment, launched an initiative to ‘shield’ some specimens of the Ebro banks: it placed meshes so that the beavers had more difficult to reach the cortex. The works began on the left bank of the river, in the Blacón de San Lázaro, one of the affected areas.
“For a few years the presence of beavers has been detected on the banks of the Ebro River, who would be demolishing trees to use them in the construction of their burrows and dams, or as food. In recent months the damages have been located in the trees of both margins of the Ebro riverbank and its tributaries” The City Council recountswhich has counted more than 70 affected specimens, especially in the section between the Ebro azud, the Yacht Club and the San Lázaro balcony. Traces have also been seen on the banks of the Huerva and Gállego.
Castores in Aragon? Exact. And this is not the first time they jump to the headlines. A year ago the farmers of the Jalón River environment already They showed their suspicion Due to the impact of these rodents on their fruit trees, an issue that even came to Congress and led the Ministry for the ecological transition to confirm that there are indications that point to the presence of beavers in the region since 2019 corroborates in statements to eldiario.es.
But … where do they come from? The story From the European beaver it is quite long. And complex. It is known that Fiber castor It was well distributed by Europe and that at the end of the 19th century it was almost on the edge of extinction, with just 1,200 copiesdue to human harassment. As we altered their habitat or pursued them to get their skins, meats or even the glands (for the perfume industry), they losing ground.
It is also known that they lived in the Iberian Peninsula, although there are different opinions about their history and the date of their collapse here. It is usually located towards the 18th, 18th or 19th century, although There are those who believe that there are hardly solid evidence that confirms the presence of rodents in Spain in recent centuries.
About what there is more consensus is how they resurfaced in the peninsula: it is usually pointed to a unauthorized loose of 18 copies in the Ebro and Aragon rivers more than two decades ago. With the passage of time the species has been extending and experts have detected it in the Tormes River, more than 300 km from the populations that had already been identified in the Ebro, or in the Guadalquivir basin.
What do we do with them? In The statement In which he informs of the nibbleed trees, the City of Zaragoza slides a key fact. Almost a paradox. While the species reintroduced without permission in the rivers of Spain, it is armored by Europe. “He Fiber Castor o European Castor is, according to the Ministry for Ecological Transition and the Demographic Challenge, a native species of Spain that was extinguished for anthropic reasons and whose current presence is a consequence of an illegal reintroduction. Despite this, community regulations force their protection. “
The theme is complex because the liberation without permission from Castores, a practice known as ‘Beaver Bombing’ and that usually carry out activists convinced of the benefits of the species for the environment, does not fit the guidelines that usually follow species reintroductions. “As established by IUCN it is necessary to carry out a series of studies that are almost common sense”, emphasize in Climate Francisco José García, expert in Mammals of the SECEM.
Why is it important? More graph was still the biologist Jacinto Román in 2023, in An interview with The country: “It is not that they are good or bad, but to know how a species that had been extinguished, studies are needed that, for now, do not exist. They cannot be made are visceral decisions.”
Cases such as last year in the surroundings of the Jalón River or on the Ebro bank as it passes through Zaragoza reflects its impact on the area. In the most urban sotos of the Aragonese capital It is known that feels predilection for poplar and poplar, although in its diet the willow, Fresno and Olmo is included, among other species. The city already remembers that only this year plans to plant more than 1,700 trees In the different districts and neighborhoods of the city that will serve to replace damaged specimens.
Images | Aivar Ruukel (Flickr), Zaragoza City Council and Wikipedia (Nasserhalaweh)
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