'Guerilla rewilding' as beavers reappear on Italy's rivers

WATCH: Giles Gibson on beaver watch in Italy

Never mind finding beavers – even finding traces of their activity takes patience in central Italy. After crossing a sodden field next to the River Tiber in the Tuscan hills, huge clumps of mud sticking to his shoes, Alessio Bariviera is using a machete to cut his way through thick undergrowth.

It has been pouring with rain all day and the river is much higher than the last time he visited. The rising water blocking his way, Bariviera doubles back and cuts his way upriver.

"We should be almost there," he tells CGTN – then he spots a tell-tale sign.  

"There, you see, look! That's a beaver sign, what we were just looking for!" he shouts, pointing to a tree that looks like it has been cut down with an ax. On closer inspection, teeth marks reveal that it was gnawed down - potentially in just one night - by an adult beaver.

‌Bariviera, a film producer whose work focuses on conservation, has been in contact with what he describes as "Beaver Believers": activists who are reintroducing the animals into the wild without official permission.

He believes these activists are frustrated with how society has treated rivers and nature in general and have decided to take matters into their own hands, potentially risking prosecution.

"By re-adding beavers, it's a cost-effective way – in fact it's free – to try to fix up some of these problems and for the better good of all people," he says. "Whereas if left to the governments themselves, these things would typically happen much more slowly, through a process that can take years."

‌Boosting biodiversity

‌Beavers disappeared from Italy around 500 years ago, but in recent years they have been spotted in several parts of the country. Scientists believe some migrated into the far north of the country from Austria about six years ago.

However, their reappearance hundreds of miles further south in Tuscany is believed to be down to a phenomenon known as "guerilla rewilding" - reintroducing species to the wild without permission from the authorities.‌

Experts have found that this practice can have unintended consequences for the local habitat. The presence of beavers has helped invasive plant species to spread in some parts of Europe.

However, according to Emiliano Mori, a researcher at Italy's Consiglio Nazionale delle Richerche, the animals are "widely considered to be ecosystem engineers."

"Illegal reintroductions often create problems in the long term. However, with the current presence of beavers, their reproductive success has been shown to be helpful for native biodiversity," says Mori.

By gnawing down trees, building dams and diverting rivers, beavers create wetlands. These have been described as among "the most productive ecosystems on earth."

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Beavers reemerge all over Europe

‌Beavers have been reintroduced - with or without official permission - in countries all over Europe, including the UK and Germany.

‌Their reappearance often triggers angry reactions from farmers and fishermen, who fear the animals will destroy fish populations or crops in fields next to rivers.

‌Along the stretch of the River Tiber in Tuscany that Bariviera showed us, local fishermen have been accused of breaking up a dam built by reintroduced beavers.

According to Mori, there may be only 40 to 50 beavers in the whole of Italy but he expects their population to rise in the years to come. As their numbers grow, they could help to rebuild damaged ecosystems along Italy's rivers.

‌But as they start coming into contact with farmers and fishermen on a more regular basis, tensions over their reintroduction could also rise.

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