Ecological impact of beaversCastor fiberandCastor canadensisand their ability to modify ecosystems

Abstract

1.The genus Castor comprises two species: the Eurasian beaver Castor fibre , and the North American beaver Castor canadensis . Both species suffered from overexploitation, but have seen a revival since the 1920s due to increased protection and reintroduction programmes. Increases in the populations and distributions of species that are able to modify ecosystems have generated much scientific interest. Here we review the available literature concerning the possible ecological impact of beaver species in the Old and New World. 2. Beavers, being ecosystem engineers, are among the few species besides humans that can significantly change the geomorphology, and consequently the hydrological characteristics and biotic properties of the landscape. In so doing, beavers increase heterogeneity, and habitat and species diversity at the landscape scale. Beaver foraging also has a considerable impact on the course of ecological succession, species composition and structure of plant communities, making them a good example of ecologically dominant species (e.g. keystone species). 3. Nevertheless, the strength of beavers' impact varies from site to site, depending on the geographical location, relief and the impounded habitat type. Consequently, they may not be significant controlling agents of the ecosystem in all parts of their distribution, but have strong interactions only under certain circumstances. We suggest that beavers can create important management opportunities in the Holarctic, and this review will help land managers determine the likely outcome of beaver activity.

Sediment and nutrient storage in a beaver engineered wetland

“…Dam and pond features can alter hydrological regimes, both locally and downstream (Polvi and Wohl, 2012; Burchsted and Daniels, 2014). The resulting increased structural heterogeneity of the environment (Rolauffs et al ., 2001) also creates a diverse range of habitats (Rosell et al ., 2005) with an increasingly recognised potential as a habitat restoration tool (Law et al ., 2017). In addition to increasing biodiversity (Law et al ., 2017), it has been suggested that, due to their engineering activity, beavers could play a role in the management of river catchments (Puttock et al ., 2017).…”

Distribution and patterns of spread of recolonising Eurasian beavers (Castor fiber Linnaeus 1758) in fragmented habitat, Agdenes peninsula, Norway

“…Assuming an average group size of 3.9 (Rosell & Parker 1995;Rosell et al 2005), the results suggest a current territoriallyresident population of about 80 individuals, plus a number of nonterritorial dispersing individuals in any year.…”

DISTRIBUTION AND POPULATION GROWTH OF EURASIAN BEAVER (Castor fiber LINNAEUS, 1758) IN BOSNIA AND HERZEGOVINA 10 YEARS AFTER REINTRODUCTION

“…However, the activity of beaver makes water systems healthy and in good condition. Their work is crucial in formation of wetland ecosystems, which in turn is used by many other species (Hägglund and Sjöberg, 1999;Baker et al, 2005;Rosell et al, 2005;Dalbeck et al, 2007;Ciechanowski et al, 2011).…”