Controlled reintroduction and conservation of beavers

Alternative Label

Beaver introduction
Beaver river reconquest
Eurasian beaver return
Eurasian beaver protection

Code

N18

Year of Issue

2025

Sponge function(s)

Slow down runoff

Temporary store runoff

Sector

Hydro Morphology

Other sector(s)

Forest

Summary

Beaver-controlled reintroduction and conservation refers to the deliberate, regulated return of the Eurasian beaver (Castor fiber) to its native habitats across Europe, where it had been brought to the brink of extinction due to centuries of hunting, chasing and habitat loss. This process is guided by ecological, hydrological, and social considerations to ensure coexistence between beavers and human land use.

Beavers are recognised as 'ecosystem engineers' due to their ability to reshape landscapes through dam-building, which significantly alters hydrology, geomorphology, and ecosystem structure.

Their activities can:

Slow water flow and attenuate flood peaks by increasing water storage and hydrological roughness,
Improve water quality through sediment capture and nutrient filtration,
Enhance drought resilience by raising groundwater levels and maintaining base flows,
Support biodiversity by creating complex wetland habitats.

These structures play a key role in altering local hydrology. By raising the water table and creating ponded areas, beaver dams promote riparian vegetation growth and provide habitat for aquatic species. Successful functioning of these systems typically requires sufficient lateral space to allow for the natural spreading of water and the rewetting of adjacent areas. The dams themselves are simple and are inherently dynamic—they can deteriorate or be washed out during flood events. However, if secondary flow paths or channels are maintained, the system can often re-establish itself naturally.This highlights the importance of verifying whether there is adequate space for lateral water movement before reintroduction, especially in more constrained or human-dominated landscapes.

While beavers action increases the diversity of flow facies, it can also lead to uncontrolled modifications of the flow paths of water over a larger portion of the river hinterland, and therefore consume space or have other impacts on human activities (cultivated trees, ...). Despite the above listed benefits, the measure remains rare and controversial, especially in intensively managed landscapes. Challenges include:

Public perception: Beavers are sometimes viewed as pests by farmers and landowners due to localized flooding and tree felling.
Scalability limits: Scientific studies show that while beaver dams can reduce flood risk locally, they are insufficient to manage flood-excess volume at a catchment or national scale.
Social carrying capacity: As populations grow, conflicts may increase, requiring adaptive management and stakeholder engagement.

The UK has recently approved licensed reintroductions as part of its natural flood management (NFM) strategy, supported by research from institutions like the University of Exeter and Devon Wildlife Trust. These efforts highlight the importance of controlled, site-specific reintroductions that balance ecological benefits with human interests.

The LIFE Beaver Project in Croatia is a compelling example of human-beaver coexistence. It showcases how a species that was almost driven to extinction has been successfully reintroduced and embraced by local communities. The project demonstrates how beavers contribute to wetland restoration, biodiversity, and climate resilience through their natural engineering of aquatic habitats, while humans adapt to and support their return. In places such as Ivanić Grad, where the first beavers were released, the species has become a symbol of ecological harmony and is now an integral part of public life and local identity.

Meanwhile, research in Sussex, UK, has demonstrated the hydrological benefits of beaver dams in a local catchment area where 84% of watercourses were found to be suitable for dam construction. Simulations showed that beaver dams increased water levels upstream and reduced inundation downstream, confirming their role in localised flood mitigation.

Together, these examples highlight the ecological potential and practical challenges of beaver reintroduction in contemporary European landscapes.

Beaver infographic