Wolves, people, and brown bears influence the expansion of the recolonizing wolf population in Scandinavia

Abstract

Abstract. Interspecific competition can influence the distribution and abundance of species and the structure of ecological communities and entire ecosystems. Interactions between apex predators can have cascading effects through the entire natural community, which supports broadening the scope of conservation from single species to a much wider ecosystem perspective. However, competition between wild large carnivores can hardly be measured experimentally. In this study, we analyzed the expansion of the Scandinavian wolf (Canis lupus) population during its recovery from the early 1990s. We took into account wolf-, habitat-, human-and brown bear (Ursus arctos)-related factors, because wolf expansion occurred within an area partially sympatric with bears. Wolf pair establishment was positively related to previous wolf presence and was negatively related to road density, distance to other wolf territories, and bear density. These findings suggest that both human-related habitat modification and interspecific competition have been influential factors modulating the expansion of the wolf population. Interactions between large carnivores have the potential to affect overall biodiversity. Therefore, conservation-oriented management of such species should consider interspecific interactions, rather than focusing only on target populations of single species. Long-term monitoring data across large areas should also help quantify and predict the influence of biotic interactions on species assemblages and distributions elsewhere. This is important because interactive processes can be essential in the regulation, stability, and resilience of ecological communities.

Habitat segregation between brown bears and gray wolves in a human‐dominated landscape

“…However, evidence of interspecific competition between sympatric large carnivores with fine‐scale data (e.g. GPS data) and at the population level is just beginning to be documented, in terms of both kill rates (Elbroch et al., ; Tallian et al., ) and habitat selection (Ordiz et al., ). Our study took advantage of the long‐term monitoring with GPS collars of brown bears and wolves in Scandinavia.…”

“…Survival and partial recovery of wolves and other large carnivores in human‐dominated landscapes seems to be determined by an interaction between environmental and human factors, which reflects on the current distribution (Llaneza, López‐Bao, & Sazatornil, ) and genetic structure of wolf populations (Hulva et al., ). Nevertheless, to obtain a comprehensive understanding of the mechanisms facilitating coexistence among sympatric apex predators, it will also be important to understand how the habitat selection of each species is influenced by the relative density of the other species and by differences in availability of resources at large (Ordiz et al., ) and finer spatial scales (e.g. this study).…”

“…In Scandinavia, moose ( Alces alces ) is the staple prey of wolves (Sand et al., , ), whereas the diet of bears includes a wide range of food items (Stenset et al., ). Nevertheless, bears are also efficient predators of neonate moose (Dahle et al., ; Swenson et al., ), and they kleptoparasitize more than half of the wolf kills during spring in central Sweden (Milleret, ; Ordiz et al., ). Bear density has a negative effect on the probability of wolf pairs establishing in a given area (Ordiz et al., ), and wolf kill rates are lower when bears are present (Tallian et al., ).…”

“…Nevertheless, bears are also efficient predators of neonate moose (Dahle et al., ; Swenson et al., ), and they kleptoparasitize more than half of the wolf kills during spring in central Sweden (Milleret, ; Ordiz et al., ). Bear density has a negative effect on the probability of wolf pairs establishing in a given area (Ordiz et al., ), and wolf kill rates are lower when bears are present (Tallian et al., ). However, no effects of wolves have ever been documented on brown bears at the population level.…”

Prey Selection of Scandinavian Wolves: Single Large or Several Small?

“…In conclusion, the presence of alternative prey species such as roe deer should result in a relaxed predation rate on the moose population [38], which in turn would be important for the harvestable surplus of both roe deer and moose. This also highlights the need for management to adopt an ecosystem approach that goes beyond simple two-species models, to instead including multiple interacting species in both the prey- and predator community [84]. …”