Photo: Marko Zabavnik

Eurasian Beaver
Castor fiber

In the past, the Eurasian Beaver was widespread in our country, but was unfortunately exterminated through indiscriminate shooting in the mid-18th century. Successful introduction of Bavarian beavers to Croatia in 1996 enabled the species to return to our territory as well. Traces of its presence can be seen along the Drava, Mura, Krka, Kolpa and few other Slovenian rivers.

Beaver dwells in and along inland waters (lakes, moors, streams and rivers). Standing aquatic habitats (lakes, ponds) are more agreeable to beavers than rivers. Crucial for its constant presence in the area is availability of water and plant food throughout the year. Beaver’s basic land habitat is riparian willow stand. In this type of habitat it evades conflicts with humans and reaches greater fertility. Maintaining woody riparian overgrowth along rivers is therefore crucial for its constant and healthy population.

Threat factors

Beaver is threatened largely by destruction of woody riparian overgrowth, filling and drying of the former river branches, oxbow lakes and depressions. A common difficulty is the proximity of farmland stretching directly along waters, where most conflicts with humans occur. Beaver’s population status is quite often badly affected by humans through their illegal activities and deeds, such as: hunting, poisoning, deliberate damage and destruction of lodges, tunnels, dams, etc.

Project activities

Within the project, we shall establish new water habitats, restore the ones existing in the past (oxbow lakes, river branches, depressions), and stimulate development of woody riparian vegetation. Furthermore, we shall indirectly contribute to a more favourable microclimate in the area and to the increase of local species diversity. To raise people’s awareness of the importance to preserve the Beaver as well as its habitats and natural river processes, educational and interpretation units will be set up.


Why do we need the Beaver?

Beaver is an influential aquatic ecosystem species, considering that its active presence alters the character of rivers and streams. It creates and maintains wetlands, expands the diversity of habitats and, in turn, has a positive impact on numerous plant and animal species. It also contributes to a more favourable local microclimate. The Beaver’s activities have a positive effect on the riparian vegetation belt that has been severely curtailed by humans, particularly in the agricultural and urban landscapes. The riparian woody plants rejuvenate, restore and create space for this aquatic mammal.

Through building dams, the Beaver slows down the water flow and causes water to spill over, which consequently causes replacement of the community of running waters with community of standing waters, which affects the species composition in invertebrates, birds, amphibians and fish. The dam built by it provides fish with a place of concealment, behind which the fry find more food. Dams do not prevent fish from migrating. Beaver increases the surface area of wetlands, which are natural water purifiers, enabling groundwater recharge. It has a significant impact on the chemistry of water. Beaver dams slow down the water flow, increase sedimentation and decrease the level of nitrogen, phosphorus and carbon accumulating in anaerobic sediments. Microorganisms behind the dam eliminate heavy metals from the water. Behind the dam, the bases and acids brought by the water are neutralized. Through mixing the water, Beaver further hastens these chemical processes and, in turn, further expedites water purification.

Beaver has a huge positive effect on the maintenance of wetlands and purification of water, which greatly exceeds the damage caused by these animals in the area. In Latvia, water purification as a result of beavers’ activities has been estimated at no less than 1.43 billion €.

What can we do to improve the Beaver's conservation status?

  • We should not pollute the water.
  • We should preserve a wide belt of riparian vegetation.
  • Beavers should not be harassed. Neither should their lodges and dams be destroyed!
  • Let's get acquainted with them. Do not be afraid of them. They are herbivorous animals that do not endanger fish populations.

Sources and literature