“Arrivés en train ou dans des oliviers”, les geckos colonisent Bordeaux depuis 2000
Through Writing Bordeaux
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November 2021. A beautiful afternoon in an apartment in sum rate a Bordeaux, where Amandine and Clément live. While one of their friends makes a brief visit to the bathroom, he finds himself face to face with the beast. “She was there motionless, on the stone wall,” says Amandine.
Called to come and observe the animal, the couple, although from Bordeaux, is unable to identify it: “It’s the first time I’ve seen something like that”. New observation two months later, when a delivery man moves the fridge. “She was underneath, it surprised the person who started screaming”.
A colonization that bears witness to climate change
“She” – “a kind of lizard which is not one” according to Amandine – is in fact a Taranto of Mauretaniaa species of gecko found in the countries of northern Africa, but also in Spain or Portugal. In France, it is observable around the Mediterranean, mainly.
But for a few years, this gecko has been going back to the north of the country. . “A consequence of global warming”, assures Matthieu Berroneau herpetologist of the Cistude association.
With the increasing temperatures, the reptile would even be permanently installed in the Metropolis of Bordeaux, without its population being able to really estimate.
Citizen science
It is for this purpose that the association for the defense of the environment has been carrying out, since 2021, a census of the species on the territory. A follow-up action, carried out over five years, within the framework of BioDiver’Cité, a large study supported by Bordeaux Metropoliswhich aims to better understand, preserve and restore the territory’s ecosystems.
Thus, as soon as the fine weather returns, Mathieu Berroneau will get on his bike, to go and explore the Tarente de Mauretania through the Metropolis.
His trick for maximizing his chances of observation? Favor the hot season, go out at night, and get closer to your favorite dishes.
The species is mainly observed at night
“The species is essentially nocturnal. It can be seen as soon as night falls, near lights, where it comes to feed on flying insects endowed with light,” explains the herpetologist, who traveled nearly 90 kilometers last year.
To complete its own observations, the association has multiplied calls on social networks. The latest publication, on the Facebook page of Community wanted, cited nearly 200 testimonials. Some recount interviews with the reptile dating back several years.
For good reason, the beginning of colonization dates back to the 2000s, according to the first reports.
The geckos took the train
How did they arrive? Because the road is long from the Mediterranean! Impossible for the tarentos of about fifteen centimeters to take the road alone, ironically the specialist: “The first were reported near the Saint-Jean station. This explains, in part, how they got to Bordeaux. »
Besides the train, the geckos also provided the “fashion” of the olive trees, imported from the south of France. Either they hide there or they lay eggs there. “Eggs only hatch if the temperature allows them to survive,” continues Mathieu Berroneau.
The strong presence of young individuals thus testifies to an adapted climate
Reduce heat islands
In one year, between the work carried out by Cistude and the messages of individuals, about fifty observations were informed. But this is not enough for scientists, who will need a sufficiently abundant database to be representative.
The study, which continues until 2026, will eventually make it possible to identify the places of life of these geckos: “It has been hypothesized that they lived in the hottest streets of the city”, underlines the searcher.
To solve it, he will overlay a map of the observations with a map of the hottest areas of the city, “where the temperature can be 3 to 4 degrees higher than the rest of the streets” he still points out.
“If the results of this study can also highlight the importance of vegetation in cooling cities, we will have won everything! »
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