Beavers: Important Allies for Greater Biodiversity

This year, Europe experienced record-breaking heatwaves and one of the worst drought periods in a century, prompting many communities to impose water restrictions.

These included bans on garden irrigation, filling paddling pools, and car washing.

In a small part of West Sussex in England, however, a very different method of combating drought is underway. In February, a pair of Eurasian beavers was introduced to the Knepp Wildland, a pioneering rewilding project on formerly agricultural land. During the recent heatwaves, the dams built by the animals have kept ponds full and soils boggy, while lowering air and ground temperatures.

Knepp Wildland is the first large lowland rewilding project in England. It encompasses 1’400 hectares of former arable and dairy farmland on the grounds of Knepp Castle in West Sussex, England.

«We have seen truly remarkable results in the five months they have been here«, says Penny Green, an ecologist at Knepp Wildland. «The beavers have already created a small network of ponds that they have dammed, they have grazed some of the vegetation in the ponds, and we have small young animals.«

«But the most remarkable thing for us is that, even though we are in a year of severe drought and most of the small streams on either side of the enclosure have dried up, the most amazing wetland oasis has formed here inside the beaver enclosure around us.»

The extensive system of ponds and canals connecting them helps branches take root and regrow, while simultaneously attracting a wide variety of animals, including dragonflies, damselflies, reed warblers, chiffchaffs, and a range of amphibians, insects, and bats. In addition, the water backed up above the dams has created further wetlands outside the enclosure, where larger mammals such as roe deer, cows, and pigs frequently come to quench their thirst.

Surprisingly, it is precisely the imperfection of beaver dams that is a key aspect in the fight against drought and biodiversity loss. «They offer opportunities during the summer months because they have slightly leaky dams«, explains Green. » In drought years like this one, when there may not be as much water in our landscapes, a little water trickles through. So they will be releasing a small amount of water from these dams throughout the summer.

The activity of beavers also plays a crucial role in cooling the environment, as deeper water at lower temperatures flows into the surrounding landscape, and evaporation from the large surface areas of the ponds helps to cool the air.

As Green argues, many of the benefits extend far beyond the hot summer months. «Beavers create all manner of wonderful habitats for other wildlife, but they also provide many ecosystem services that benefit us humans. They help reduce flooding by holding back water, especially during the heavy rainfall events we experience. They retain water and slow runoff, which is fantastic.«

In light of these various climate benefits brought about by beaver activity, the British government has finally placed these resilient ecosystem engineers under legal protection, prohibiting the deliberate capture, killing, and injuring of them, as well as the damaging of their lodges and dams. In our fight against climate change, these fascinating creatures could prove to be among our most unexpected yet most powerful allies.