The forgotten prey of an iconic predator: a review of interactions between grey wolvesCanis lupusand beaversCastorspp.

Abstract

1.Predator-prey relationships can have wide-ranging ecological and landscapelevel effects. Knowledge of these relationships is therefore crucial to understanding how these systems function and how changes in predator-prey communities affect these systems. Grey wolves Canis lupus can be significant predators of beavers Castor spp., and conversely, beavers can be important prey for wolves, but wolf-beaver dynamics in North America, Europe, and Asia are poorly understood. 2. Our objectives were to synthesise current knowledge regarding wolf-beaver interactions and to identify knowledge gaps that should be targeted for study to increase our understanding of wolf-beaver dynamics. 3. During the ice-free season, beavers are vulnerable to predation and can be the primary or secondary prey of wolves, but the factors that affect beaver consumption by wolves are complex and are likely dependent on biological and environmental factors. 4. High beaver abundance can increase wolf pup survival, and beavers may subsidise wolves during periods of reduced ungulate abundance. Thus, many researchers have suggested that beaver densities adversely affect ungulate populations through apparent competition, though this remains largely untested. 5. The effects of wolf predation on beaver population dynamics are poorly understood, as most assessments are lacking in quantitative rigor and are instead based on indirect methods (e.g. scat analysis), anecdotal evidence, or speculation. To understand the effect of predation on beaver populations fully, better estimates (e.g. from documented predation events) of wolf predation on beavers are necessary. 6. Given the complexities of wolf-ungulate-beaver systems, fully understanding wolf-beaver dynamics will be challenging and is likely to require long-term, intensive research of wolf, ungulate, and beaver population parameters.Understanding this dynamic has implications, not only for the conservation and management of wolves and beavers, but also for ungulate populations, which are affected by the numerical and functional responses of wolves in these same systems. Mammal Review ISSN 0305-1838 bs_bs_banner Mammal Review 48 (2018) 123-138

A Review of Beaver–Salmonid Relationships and History of Management Actions in the Western Great Lakes (USA) Region

“…Given that beavers have been shown to be an important food source for wolves (Mech ; Gable et al. , ), even accounting for up to 50% of seasonal wolf diets (Voigt et al. ; Gable et al.…”

“…; Gable et al. ), suppressed wolf populations could have allowed for beaver population expansion at an even faster rate (Hartman ); however, there is little evidence to suggest this is the case (Gable and Windels ; Gable et al. ).…”

“…), suppressed wolf populations could have allowed for beaver population expansion at an even faster rate (Hartman ); however, there is little evidence to suggest this is the case (Gable and Windels ; Gable et al. ). American black bears Ursus americanus , coyotes Canis latrans , bobcats Lynx rufus , Canada lynx L. canadensis , and mountain lions Felis concolor also occasionally prey upon beavers (Baker and Hill ), and reduced populations of these other predators through the 1970s may have contributed to the rapid beaver expansion.…”

Local knowledge about a newly reintroduced, rapidly spreading species (Eurasian beaver) and perception of its impact on ecosystem services

“…with the literature and SCE information regarding both distance reached from waterbodies [44,54] and predators [55].…”

Dam busy: beavers and their influence on the structure and function of river corridor hydrology, geomorphology, biogeochemistry and ecosystems

“…However, if the competitive interactions can be reduced, e.g. via predator re-introduction (Beschta and Ripple, 2019;Gable et al, 2018) (see also section 9.1), or because the meadow already supports a more diverse and productive browsing assemblage, browsing pressure from elk may instead lead to competitive exploitation, in which beavers are able to adapt their foraging behavior without abandoning the site (Hood and Bayley, 2008b). A notable example of this latter feedback is the recovery of beaver meadows in Yellowstone National park (USA), were predator reintroduction is hypothesized to have reduced elk browsing pressure, allowing willow recovery and beaver recolonization (Wolf et al 2007).…”