An official website of the United States government
Apex predators exert suppressive effects on mesocarnivores; however, they also provide important carrion subsidies. Optimal foraging theory predicts that individuals respond to resource competition by using high-value resources, while competition theory predicts that individuals respond by partitioning resources. This study investigated how the return of wolves ( Canis lupus Linneas, 1758) to Washington state impacted the diet of a subordinate carnivore—the coyote ( Canis latrans Say, 1823). We collected coyote scats from two areas of northern Washington with differing wolf densities and used traditional analysis of undigested remains to infer diet. We tested for differences in the volumes of prey categories, the proportion of ungulate prey that was scavenged, and diet diversity between seasons, study sites, and inside and outside of wolf pack territories. Coyote scats contained more adult ungulate remains inside of wolf pack territories (27%) compared to outside (14%), while seeds and berries were more commonly consumed outside of wolf pack territories (23%) than inside of wolf pack territories (4%). These findings suggest that coyotes are taking advantage of wolf kills to increase ungulate carrion consumption, as predicted by optimal foraging theory, which may substantially affect plant and wildlife communities as wolves continue to recover and coyote diets shift in response.
more »
« less
Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups
Abstract Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group‐level processes such as subgroup formation and fission–fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals. We tracked 574 individuals from six species within the genusCanisin 15 countries on four continents with GPS telemetry to estimate the time that pairs of individuals within social groups spent in close proximity and test hypotheses regarding drivers of cohesion. Pairs of social canids (Canisspp.) varied widely in the proportion of time they spent together (5%–100%) during seasonal monitoring periods relative to both intrinsic characteristics and environmental conditions. The majority of our data came from three species of wolves (gray wolves, eastern wolves, and red wolves) and coyotes. For these species, cohesion within social groups was greatest between breeding pairs and varied seasonally as the nature of cooperative activities changed relative to annual life history patterns. Across species, wolves were more cohesive than coyotes. For wolves, pairs were less cohesive in larger groups, and when suitable, small prey was present reflecting the constraints of food resources and intragroup competition on social associations. Pair cohesion in wolves declined with increased anthropogenic modification of the landscape and greater climatic variability, underscoring challenges for conserving social top predators in a changing world. We show that pairwise cohesion in social groups varies strongly both within and acrossCanisspecies, as individuals respond to changing ecological context defined by resources, competition, and anthropogenic disturbance. Our work highlights that cohesion is a highly plastic component of animal sociality that holds significant promise for elucidating ecological and evolutionary mechanisms underlying cooperative behavior.
more »
« less
- PAR ID:
- 10666591
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- ESA
- Date Published:
- Journal Name:
- Ecology
- Volume:
- 106
- Issue:
- 1
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)Understanding how mesopredators manage the risks associated with apex predators is key to explaining impacts of apex predators on mesopredator populations and patterns of mesopredator space use. Here we examine the spatial response of coyotes (Canis latrans Say, 1823) to risk posed by wolves (Canis lupus Linnaeus, 1758) using data from sympatric individuals fitted with GPS collars in subarctic Alaska, USA, near the northern range limit for coyotes. We show that coyotes do not universally avoid wolves, but instead demonstrate season-specific responses to both wolf proximity and long-term use of the landscape by wolves. Specifically, coyotes switched from avoiding wolves in summer to preferring areas with wolves in winter, and this selection was consistent across short-term and longer term temporal scales. In the summer, coyotes responded less strongly to risk of wolves when in open areas than when in closed vegetation. We also demonstrate that coyotes maintain extremely large territories averaging 291 km 2 , and experience low annual survival (0.50) with large carnivores being the largest source of mortality. This combination of attraction and avoidance predicated on season and landcover suggests that mesopredators use complex behavioral strategies to mediate the effects of apex predators.more » « less
-
Hopkins, Jack (Ed.)Abstract Carrion represents an important resource for carnivores. Examining competition for carrion in a risk–reward framework allows for a better understanding of how predator guilds compete for and benefit from carrion. We used trail camera data to compare wintertime carrion use and vigilance behavior of four carnivores in Denali National Park and Preserve. We found that carrion use was dominated by wolves (Canis lupus) and wolverines (Gulo gulo), followed by red foxes (Vulpes vulpes) and coyotes (Canis latrans). Wolves and wolverines were twice as likely to visit a carcass as foxes and coyotes, and their visits were longer and more numerous. Our results suggest scavenging animals reduced their risk exposure primarily by reducing their use of carrion, with some evidence of increased vigilance at busy sites. We found that carrion use and behavior at carcass sites were influenced by the mortality type of the carcass, the age of the carcass, and the long-term intensity of wolf use in the area. Our results also suggest that wolves are the “top scavenger,” and indicate that intraguild competition for carrion strongly affects which species benefit from carrion, with larger and more aggressive species dominating.more » « less
-
Abstract The number and distribution of animals in space form the basis of many wildlife studies. Yet, reliable estimation of population abundance remains challenging. Generalized spatial mark‐resight (gSMR) models are widely applicable abundance estimators that do not require all individuals be uniquely identifiable. Despite their flexibility, gSMR models assume independence in distribution and detections of individuals throughout space. Group‐living species that aggregate (i.e. share activity centres) and move cohesively (i.e. share detections) violate these assumptions, limiting the applicability of gSMR models to solitary species with limited home range overlap.We developed a gSMR model that accounts for group associations to estimate spatial abundance. We treated groups as the measurable ‘units’ and included a submodel that uses Poisson processes to estimate group size. We conducted a simulation study to compare our novel group‐based gSMR to a gSMR that ignores group associations. We generated data across varying levels of aggregation and cohesion parameters. We then quantified and compared the precision and bias of parameter estimates between the two models.The group‐based gSMR model outperformed the individual‐based gSMR under all aggregation and cohesion scenarios. Group‐based 95% Bayesian Credible Intervals (BCI) overlapped the true value of abundance in 91% of simulations, compared to only 15% of simulations in the individual‐based gSMR. Both the group‐based and individual‐based models became less precise and more biased as aggregation and group size increased. However, the group‐based gSMR model was less biased in estimating all parameters when compared to the individual‐based gSMR model.We applied our group‐based gSMR model to grey wolf (Canis lupus) monitoring data within a Canadian national park complex (Banff, Yoho and Kootenay National Parks, and Ya Ha Tinda). We used 12 years (2012–2023) of remote camera data, along with information from GPS radio‐collared wolves (N = 16) to estimate spatiotemporal variation in abundance. Over a 12‐year period, wolf abundance averaged 73 (95% BCI = 20–207) individuals, and a density of 6.69 (95% BCI = 1.83–19.0) wolves per 1000 km2within the park complex. Our novel group‐based gSMR model extends the applicability of spatial mark‐resight to species with group associations.more » « less
-
Social learning, information transmission and culture play vital roles in the lives of social animals, influencing their survival, reproduction and ability to adapt to changing environments. However, the effect of anthropogenic disturbances on these processes is poorly understood in free-living animals. To investigate the impact of anthropogenic disturbance on social learning and information transmission, we simulated individual removal from contact networks derived from long-term behavioural datasets. We simulate the effects of individual removal on network efficiency and social learning for three group-living species—yellow baboons (Papio cynocephalus), African savanna elephants (Loxodonta africana) and Indo-Pacific bottlenose dolphins (Tursiops aduncus). We reveal how removals of key network positions reduce network efficiency. However, groups with high levels of innovation may cope with changing social network structures. These findings highlight the importance of protecting key individuals to preserve group structure and the role of innovation in possibly mitigating the fitness costs of removals. Identifying and safeguarding individuals that drive innovation can reduce a group’s susceptibility to anthropogenic threats and promote cultural resilience in social animals in a changing world. These emerging trends contribute to a growing understanding of the role of conservation interventions in protecting critical individuals in group-living animals. This article is part of the theme issue ‘Animal culture: conservation in a changing world’.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/ecy.4492
