Individual Variation in Predatory Behavior, Scavenging and Seasonal Prey Availability as Potential Drivers of Coexistence between Wolves and Bears

Ordiz, Andrés; Milleret, Cyril; Uzal, Antonio; Zimmermann, Barbara; Wabakken, Petter; Wikenros, Camilla; Sand, Håkan; Swenson, Jon E.; Kindberg, Jonas

doi:10.3390/d12090356

Cited by 23 publications

(20 citation statements)

References 57 publications

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“…The selection coefficient for distance to kill still was not statistically significant when male and female bears were modeled separately; however, the direction of the coefficient suggested male bears tended to be slightly attracted to kill sites while female bears tended to avoid them (SI Appendix, Text S13, Table S11). This accords with previous studies of brown bears wherein females with cubs had a lower propensity to scavenge than males (41).…”

Section: Discussionsupporting

confidence: 92%

Games of risk and reward in carnivore communities

Ruprecht¹,

Eriksson²,

Forrester

et al. 2021

Preprint

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Mesopredator release theory suggests that dominant predators suppress subordinate carnivores and ultimately shape community dynamics, but the assumption that subordinate species are only negatively affected ignores the possibility of facilitation through scavenging. We examined the interplay within a carnivore community consisting of cougars, coyotes, black bears, and bobcats using contemporaneous Global Positioning System telemetry data from 51 individuals, diet analysis from 972 DNA-metabarcoded scats, and data from 128 physical investigations of cougar kill sites, 28 of which were monitored with remote cameras. Resource provisioning from competitively-dominant cougars to coyotes through scavenging was so prolific as to be an overwhelming determinant of coyote behavior, space use, and resource acquisition. This was evident via strong attraction of coyotes to cougar kill sites, frequent scavenging of cougar-killed prey, and coyote diets that nearly matched cougars in the magnitude of ungulate consumption. Yet coyotes were often killed by cougars and used space to minimize encounters, complicating the fitness benefits gained from scavenging. We estimated that 23% (95% CI: 8–55%) of the coyote population in our study area was killed by cougars annually suggesting that coyote interactions with cougars are a complex behavioral game of risk and reward. In contrast, we found no indication that bobcat space use or diet was influenced by cougars. Black bears avoided cougars, but there was no evidence of attraction to cougar kill sites, and much lower levels of ungulate consumption and carcass visitation than for coyotes. Interspecific interactions among carnivores are multifaceted encompassing both suppression and facilitation.Significance StatementAn incomplete understanding of the total influence top predators exert on subordinate species hinders our ability to anticipate the effects that changing carnivore populations will have in ecological communities. Here we show that cougars are the architects of a complex behavioral game of risk and reward, as subordinate or co-occurring carnivores are both provisioned and preyed on by the top predators. Each co-occurring carnivore species considered here employed a different strategy to approach the risk-reward tradeoff suggesting there are multiple viable solutions to the game. By not considering the multitude of effects top predators have on other carnivores, we are missing important linkages in terrestrial food webs.

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Section: Discussionsupporting

confidence: 92%

Games of risk and reward in carnivore communities

Ruprecht¹,

Eriksson²,

Forrester

et al. 2021

Preprint

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“…Today, recovery of several overlapping species in some areas provides opportunities for the recovery of complete guilds and their interactions. That is the case for northern Eurasia, for instance, where wolves, bears, lynx, and wolverines have expanded in recent times [9,15], favoring interspecific interactions [65,194]. Further research should document the effects that carnivore sympatry may trigger on lower trophic levels, including prey and other species, provided that recovery continues in the near future.…”

Section: Management Considerationsmentioning

confidence: 99%

“…As large carnivores in general, the brown bear is threatened by human-caused mortality, habitat fragmentation, and habitat loss [64]. Brown bears and other bear species are efficient predators of ungulates, especially calves [65,66]. As omnivores, bears also eat insects, fish, and plants, i.e., a diverse foraging behavior linked to several ecological effects.…”

Section: Of Wolves and Bears And Beyond-examples Of Apex Predator Efmentioning

confidence: 99%

Effects of Human Disturbance on Terrestrial Apex Predators

et al. 2021

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The effects of human disturbance spread over virtually all ecosystems and ecological communities on Earth. In this review, we focus on the effects of human disturbance on terrestrial apex predators. We summarize their ecological role in nature and how they respond to different sources of human disturbance. Apex predators control their prey and smaller predators numerically and via behavioral changes to avoid predation risk, which in turn can affect lower trophic levels. Crucially, reducing population numbers and triggering behavioral responses are also the effects that human disturbance causes to apex predators, which may in turn influence their ecological role. Some populations continue to be at the brink of extinction, but others are partially recovering former ranges, via natural recolonization and through reintroductions. Carnivore recovery is both good news for conservation and a challenge for management, particularly when recovery occurs in human-dominated landscapes. Therefore, we conclude by discussing several management considerations that, adapted to local contexts, may favor the recovery of apex predator populations and their ecological functions in nature.

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“…Although kill rates upon moose neonates are high, they vary between individuals with reported rates ranging from 2% to 52% [18]. Moose predation by brown bears adds to the predation by wolves, where they overlap [19][20][21], and other large carnivores [22], as well as human induced mortality from roads and infrastructure.…”

Section: Introductionmentioning

confidence: 99%

“…Large individual variation has been shown in bear habitat selection [26] and bear kill rates [14,21]. The latter parameter implies different levels of specialization reflecting individual differences in foraging behaviour [27], which may help explain the large individual variation in bear habitat selection [28].…”

Section: Introductionmentioning

confidence: 99%

Habitat Selection by Brown Bears with Varying Levels of Predation Rates on Ungulate Neonates

et al. 2021

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In northern Eurasia, large carnivores overlap with semi-domestic reindeer (Rangifer tarandus) and moose (Alces alces). In Scandinavia, previous studies have quantified brown bear (Ursus arctos) spring predation on neonates of reindeer (mostly in May) and moose (mostly in June). We explored if habitat selection by brown bears changed following resource pulses and whether these changes are more pronounced on those individuals characterised by higher predatory behaviour. Fifteen brown bears in northern Sweden (2010–2012) were fitted with GPS proximity collars, and 2585 female reindeers were collared with UHF transmitters. Clusters of bear positions were visited to investigate moose and reindeer predation. Bear kill rates and home ranges were calculated to examine bear movements and predatory behaviour. Bear habitat selection was modelled using resource selection functions over four periods (pre-calving, reindeer calving, moose calving, and post-calving). Coefficients of selection for areas closer to different land cover classes across periods were compared, examining the interactions between different degrees of predatory behaviour (i.e., high and low). Bear habitat selection differed throughout the periods and between low and high predatory bears. Differences among individuals’ predatory behaviour are reflected in the selection of habitat types, providing empirical evidence that different levels of specialization in foraging behaviour helps to explain individual variation in bear habitat selection.

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Individual Variation in Predatory Behavior, Scavenging and Seasonal Prey Availability as Potential Drivers of Coexistence between Wolves and Bears

Cited by 23 publications

References 57 publications

Games of risk and reward in carnivore communities

Games of risk and reward in carnivore communities

Effects of Human Disturbance on Terrestrial Apex Predators

Habitat Selection by Brown Bears with Varying Levels of Predation Rates on Ungulate Neonates

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