Eurasian Beaver

Castor fiber

The Eurasian beaver Castor fiber bearing its orange incisor teeth

Like their North American counterparts, Eurasian beavers are capable of shaping their habitats in amazing ways.

Range map of the Eurasian beaver

A wet Eurasian beaver carrying a stalk of plant near a lakeside habitat. Click for larger image.

Beavers use a variety of materials to build their dams, including branches, rocks, and mud. Photo credit: iStock/Getty Images Plus

Beavers are well-known for building dams, large structures in rivers and streams that can cause flooding and create new habitats. In this way, beavers act as ecosystem engineers: organisms that create, change, or maintain habitats. The Eurasian beaver has played a key role in shaping marsh habitats across Europe and Asia. In the 1800s, however, farmers began draining the marshes in order to turn them into cattle pastures. The beaver population nearly died out, and these habitats lost a lot of biodiversity.

Eurasian Beaver (Castor fiber)

In the early 2000s, scientists began reintroducing pairs of beavers to these habitats. As the beavers settled in, they built dams that transformed the terrain. Other plant and animal species took advantage of newly available niches, and biodiversity increased. Today, the habitats where beavers were reintroduced have been restored to a healthier, more natural state.

A meadow ecosystem showing low diversity of of plant species. Click for larger image.

A meadow, formerly a cattle pasture, in 2003: one year after beavers were reintroduced. It contains relatively few plant species. Photo courtesy of Alan Law

A healthy marsh habitat with high plant diversity after beaver reintroduction. Click for larger image.

The meadow in 2014: 12 years after the beavers were reintroduced. The number of plant species has increased. Photo courtesy of Alan Law