The Eurasian Beaver Handbook

Beavers (i.e. the Eurasian beaver, Castor fiber, and the North American – sometimes referred to as Canadian – beaver, C. canadensis) are unique mammals that often capture people’s fascination. These are large rodents, with specialised features such as their flat scaly tails, and distinctive behaviours including tree-felling and dam-building. Few other animals, apart from humans, have the ability to modify so drastically their surrounding environments. Beavers play a key role in wetland ecology and species biodiversity, providing vital ecosystem services including habitat creation, water management and quality improvement, and sediment retention. At the same time, these beaver activities can also present real challenges for land and wildlife managers.

The history of the Eurasian beaver represents an important case study for conservation and reintroduction programmes. By the late 19th century, the once widespread Eurasian beaver was reduced to a handful of relict populations in fragmented refugia across Europe, in which potentially 1,000–2,000 individuals survived (Nolet and Rosell 1998). As beaver populations dwindled, so did the understanding of living with this species pass from common knowledge. In the beavers’ absence, landscapes continued to be altered by humans, and riparian environments in particular were engineered to suit agricultural and industrial needs. By the early 20th century, naturalists tended erroneously to believe that beavers were solely a species found in ‘open woods alongside rivers, old river beds and lakes’ (van den Brink 1967) and limited in distribution by habitat suitability.

Figure 1.1 Eurasian beaver feeding on water lilies at the Scottish Beaver Trial. (P. Price)

Since then, Eurasian beavers have been restored to much of their former native range through proactive reintroductions and translocations (Halley et al. 2012). Contemporary experience of expanding beaver populations across Europe and North America demonstrates clearly that beavers can readily modify even heavily engineered landscapes to suit their own ecological requirements. The two extant beaver species, the Eurasian and the North American, inhabit wetlands and water bodies from north of the Arctic Circle, where they can endure five months of darkness and ice, to the everglades of subtropical Florida. The dry, arid environment of the Ulungaur watershed in Mongolia contains one of the last remaining Far Eastern beaver populations. Intensively utilised, cultural landscapes dominated by agricultural production with amenity woodlands, recreational areas and engineered water bodies are relatively unchallenging environments for beavers. Although it has been well demonstrated that environmental factors such as topography, hydrology and vegetation influence beaver distribution (Schwab et al. 1992; Rosenau 2003; Rosell et al. 2005), they are clearly a much more adaptive species than was initially believed.

The Eurasian beaver is a well-studied species capable of providing biodiversity and economic benefits through its natural activities. Its restoration is considered internationally to be a clear conservation success (Halley and Rosell 2002). While initially some countries (such as Finland and Russia) restored beavers to support a commercial fur trade, the majority of recent reintroductions have been implemented for nature conservation purposes. This emphasis has been prompted by a greater awareness of the ecological benefits which accrue from the presence of beavers.

The return of the beaver through a combination of reintroductions and natural recolonisation has often been viewed as a novel phenomenon. When beaver populations initially re-establish, the physical impact of their activities is often confined to a small group of land-users such as farmers, foresters or water authorities (Siemer et al. 2013). As beaver populations increase, the novelty of their presence can be replaced by hostility from wider elements of society when more visible impacts occur such as the felling of specimen trees in public parks, orchards or gardens. It is inevitable that a process whereby people ‘rediscover’ what it means to live with beavers will become a critical component of coexistence. Understanding, tolerance and a willingness to manage undesirable aspects of beaver activity competently will also be of fundamental importance.

Figure 1.2 Beaver-occupied site (>20 years), Norway. The beaver lodge is located on the small islet near the centre of the photograph. The lodge is 2 km downstream from a hydroelectric dam so water levels can vary abruptly. Although beaver signs are evident on the ground, the overall tree structure remains largely unaffected, and many people are unaware of the beavers’ presence. (D. Halley)

Figure 1.3 Tree-coppicing near the Deutsches Museum, in downtown Munich, an area first occupied by beavers around 2000. (R. Campbell-Palmer)

Figure 1.4 Signs of beaver activity along an urban canal (Freising, Bavaria) where house-owners regularly feed beavers. (R. Campbell-Palmer)

Figure 1.5 Beaver-created wetland habitat in agricultural areas in Bavaria. Various beaver-management techniques may be required, especially in modified environments. These may include flow devices, fencing, land purchase for conservation, trapping and removal. Where these can be planned and implemented, beavers can diversify an area and provide biodiversity hotspots in close proximity to other human land uses. (R. Campbell-Palmer)

This handbook considers a broad range of issues which are likely to arise over time as beavers are re-established, particularly with respect to British landscapes, but also elsewhere in Europe. It affords a practical overview of the implications of beaver restoration and the management requirements. Most of the information presented here addresses the experiences gained from beaver restoration in Europe, but draws from practical experiences in North America where beaver populations have also recovered. The handbook describes the animals’ field signs, lifestyle, their effects on the environment and appropriate mitigation techniques, as supposed to any wider-scale, long-term management strategy at a national level. In relation to Britain, the Eurasian beaver has not yet been formally reintroduced despite being an Annex IV species on the European Habitats Directive, although licensed trial reintroductions have occurred in Scotland (Scottish Beaver Trial) and most recently in England (Devon Beaver Trial). If the decision is made that beavers should remain, then it is anticipated their domestic legal status will change, and management strategies will be developed. We recommend that advice and necessary permission should be sought from the appropriate Statutory Nature Conservation Organisations (SNCOs) before employment of any mitigation measures.

Key concepts

•Beavers modify their environment and play a key role in wetland ecology and biodiversity.

•Beavers have been restored to much of their former native range from near-extinction following human exploitation.

•Understanding of beaver ecology, tolerance and a willingness to competently manage undesirable aspects of their behaviours are fundamental to living with this species again.

•This handbook discusses the implications of beaver restoration and likely management requirements in a British context.