2023-06-14 12:04:05
A puma walking through the streets of Santiago, Chile – in April 2020, the images went around the world. In fact, it was the sixth time in less than a month that a big cat had paced the streets of the capital, deserted by the strict lockdown implemented in the city to combat Covid-19. The following year, a US team published a study in Current Biology analyzing the movements of six cougars – the North American name for the feline – during the periods of lockdown imposed in the San Francisco Bay Area. They found that the big cats had indeed moved closer to urban areas.
Since then, various studies, sometimes with divergent conclusions, have examined the behavior of deer, wild boar, badgers and crows during what is now customarily called the anthropause. But the article published on Friday, June 9, in the journal Science appears to have a different scope. Signed by 175 scientists from 164 institutions around the world, it scrutinizes the behavioral changes of 43 species of land mammals when we give them free rein. Lions, giraffes, elephants, antelopes, gazelles, as well as brown bears, caribou, giant anteaters and ibex: 2,300 individuals were tracked in minute detail. And the results are striking. Where humans saw their mobility reduced, animals increased theirs.
A complex question
The result may seem trivial. In fact, it answers a complex question that had been gnawing at environmental scientist Marlee Tucker, from Radboud University in Nijmegen, the Netherlands, for the past five years. In 2018, she established that animal movements were reduced where the human footprint was most significant. “But we were unable to separate the effects caused by landscape changes, such as agricultural expansion, and human mobility itself,” she explained. Were animals fleeing asphalt and cultivated land, or cars, tractors and their drivers?
Lockdown offered an unexpected opportunity to disentangle the two factors. In previous years, the mammals studied had all been fitted with collars equipped with GPS sensors – a practice that has become commonplace for analyzing the behavior of wild species. By recording the animals’ movements during the silent spring of 2020 and comparing them with observations made the previous year on the same animals and the same terrain, they were able to isolate the effects of human mobility alone.
It was a life-size experiment. In strict lockdown zones, as in France, the longest journeys, recorded over a 10-day period, increased by 73% compared to the same period the previous year. The human barriers were gone. “We didn’t expect such figures,” Tucker said. On the hour-by-hour readings, there was a 12% decrease in movements, a sign for the scientists that the animals had undergone less disturbance. This interpretation is corroborated by a third observation. Taking all species together, animals moved 36% closer to roads. Conversely, in places such as the Netherlands where the authorities adopted flexible lockdowns and encouraged the population to get out in nature, the animals reduced their long-distance movements.
You have 13.26% of this article left to read. The rest is for subscribers only.
1687075134
#Mammal #movements #boosted #human #lockdowns