Article

Rapid ecological and behavioural changes in carnivores: The responses of black bears (Ursus americanus) to altered food

Wiley
Journal of Zoology
Authors:
  • Colorado State University and the Wildlife Conservation Society
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Many areas have experienced disproportionate increases in the number of conflicts between large carnivores and humans, and this is especially true in western North America where urban sprawl has encroached into regions that have historically contained large carnivores. Yet, globally there is a paucity of studies of temporal changes in behavioural and ecological parameters of carnivores associated with human-induced perturbations at the same location. We capitalized on the extent to which human population growth and its coincident food stores offer a quasi-experimental setting to test hypotheses about the impact of novel food resources. Using black bears Ursus americanus and garbage, measures of behaviour and ecology were contrasted between individuals living in urban–wildland interface (‘experimental’) and in wildland (‘control’) settings at the interface of the Sierra Nevada Range and the Great Basin Desert in the western United States. A temporal dimension was included by comparing our data to those from the same population lacking areas of human encroachment 10–15 years earlier. Specifically, an examination was made of the impacts of garbage on bear time budgets, patterns of activity, and den chronology. Individuals at urban interface areas relative to wildland conspecifics were: (1) active for significantly fewer h per day (8.5 vs 13.3 h; P<0.01); (2) shifted their activities to nocturnal periods (P<0.001); (3) entered dens significantly later and remained in them for significantly fewer days (P<0.05). Our results are contrasted with selected carnivores from sites where attendant changes in behaviour and ecology have accompanied landscape changes associated with human activity. Our findings suggest alterations in carnivore ecology may be rapid and occur within shorter periods than had been previously assumed.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Timing of entry and exit from dens is also an important aspect of den occupation, and could affect both body condition of bears and reproductive success (López-Alfaro et al., 2013). Previous work has demonstrated differences in chronology of den entrance and exit between females and males; generally, males enter dens later and remain in the den for a shorter amount of time than do females (Beckmann & Berger, 2003;Fowler et al., 2019;Waller et al., 2012). Females have higher reproductive demand than males because of pregnancy and parturition, and therefore may enter the den earlier and exit later because of those demands (Doan-Crider & Hellgren, 1996;Friebe et al., 2014). ...
... The study area consists of two eco-regions in northwest Nevada, USA: the Sierra Nevada Mountains east of Lake Tahoe (eastern Sierra Nevada) and the western Great Basin (Figure 1). This study area is unique in that it is one of the driest regions occupied by black bears, and there is a large wildland-urban interface, meaning bears may forage in human occupied areas, but den in wildlands (Beckmann & Berger, 2003;van Manen et al., 2019). While black bears may now be found across much of Nevada (Lackey et al., 2013) Land cover differs between these eco-regions: the eastern Sierra Nevada is characterized by tree species, which includes ponderosa pine (Pinus ponderosa), Jeffrey pine (Pinus jeffreyi), lodgepole pine (Pinus contorta), and mountain hemlock (Tsuga mertensiana) (Andreasen et al., 2021). ...
... The Great Basin predominantly consists of mixed sagebrush (A. tridentata) and woodlands dominated by single-leaf pinyon pine (Pinus monophylla) and Utahjuniper (Juniperus osteosperma) (Andreasen et al., 2021;Beckmann & Berger, 2003;Lackey et al., 2013;Wynn-Grant et al., 2018). At ...
Article
Full-text available
Use of dens during winter is an important strategy for American black bears (Ursus americanus) for both energy conservation and reproduction; and occupancy of suitable den sites has implications for reproductive fitness. Denning strategies may change as a result of changing climatic conditions and habitat loss. Black bears occupy arid environments in the eastern Sierra Nevada and the western ranges of the Great Basin Ecosystem. Our objectives were to identify: (1) which physical characteristics of habitat influenced selection of den sites at multiple spatial scales and (2) which environmental factors influenced timing of entrance and exit of dens by females and males. We evaluated selection of den sites by black bears at three spatial scales (300, 1000, and 4000 m) from 2011 to 2022. Terrain ruggedness was important for selection of den sites at all spatial scales. Within a 300‐m buffer from the den, bears selected den sites with rugged terrain, lower horizontal visibility, and greater canopy cover, resulting in more concealment and protection than that of the surrounding environment. Within 1000‐ and 4000‐m buffers around each den, bears selected den sites with rugged terrain, northern aspects, and steep slopes. At the 4000‐m scale, we observed interactions between sex with slope and distance to roads; females selected den sites on steeper slopes and closer to roads than did males. Females remained in the dens longer than males by entering earlier in the autumn and exiting later in the spring. Male bears exited their dens earlier with increasing consecutive days above freezing temperatures, but that relationship was weak for females. Knowing what characteristics are important for selection of den sites, and influence timing of denning, will be important for understanding how shifting climatic patterns will affect bears, particularly in arid environments that may be prone to wider fluctuations in climatic drivers of denning in the future.
... Prior research in different contexts has concluded that cougars may show immediate temporal avoidance of people [28,49], and both coyotes and bobcats may shift from primarily crepuscular to nocturnal when humans are present [25,28,36]. Likewise, we predicted black bears would segregate temporally from humans due to associated risk of injury or death when selecting for areas of higher human presence [50]. Black-tailed deer are commonly crepuscular, but are known to exhibit little-to-no crepuscular or nocturnal activity in a predator-free area [51]. ...
... Prior studies have indicated that black bears may be displaced by recreation [43], and/or vehicles used in research or forest management operations [44], but these studies characterized displacement differently (e.g., attraction-avoidance ratios, weekly habitat use). Little research has reported impacts of human activity on black bear diel activities, and of those which did, black bears were found to be more nocturnal at urban interface areas [50], to adjust their diel activities in response to seasonality [76], and/or to maintain mostly crepuscular activity patterns regardless of external influences [77]. Therefore, we provide a novel account of black bears being more nocturnal in response to direct measures of human activity. ...
... Therefore, we provide a novel account of black bears being more nocturnal in response to direct measures of human activity. We speculate this behavior may be due to the increased risk of wildlife destruction that black bears face in areas of higher human influence [50], which thereby imposes stronger incentive to reduce temporal overlap with humans. Likewise, since black bears were the least nocturnal of the species we considered (Fig 2), they may be more likely to shift their temporal niche to accommodate primarily diurnal humans relative to other species that maintain more natural temporal niche segregation. ...
Article
Full-text available
Wildlife species may shift towards more nocturnal behavior in areas of higher human influence, but it is unclear how consistent this shift might be. We investigated how humans impact large mammal diel activities in a heavily recreated protected area and an adjacent university-managed forest in southwest British Columbia, Canada. We used camera trap detections of humans and wildlife, along with data on land-use infrastructure (e.g., recreation trails and restricted-access roads), in Bayesian regression models to investigate impacts of human disturbance on wildlife nocturnality. We found moderate evidence that black bears (Ursus americanus) were more nocturnal in response to human detections (mean posterior estimate = 0.35, 90% credible interval = 0.04 to 0.65), but no other clear relationships between wildlife nocturnality and human detections. However, we found evidence that coyotes (Canis latrans) (estimates = 0.81, 95% CI = 0.46 to 1.17) were more nocturnal and snowshoe hares (Lepus americanus) (estimate = -0.87, 95% CI = -1.29 to -0.46) were less nocturnal in areas of higher trail density. We also found that coyotes (estimate = -0.87, 95% CI = -1.29 to -0.46) and cougars (Puma concolor) (estimate = -1.14, 90% CI = -2.16 to -0.12) were less nocturnal in areas of greater road density. Furthermore, coyotes, black-tailed deer (Odocoileus hemionus), and snowshoe hares were moderately more nocturnal in areas near urban-wildland boundaries (estimates and 90% CIs: coyote = -0.29, -0.55 to -0.04, black-tailed deer = -0.25, -0.45 to -0.04, snowshoe hare = -0.24, -0.46 to -0.01). Our findings imply anthropogenic landscape features may influence medium to large-sized mammal diel activities more than direct human presence. While increased nocturnality may be a promising mechanism for human-wildlife coexistence, shifts in temporal activity can also have negative repercussions for wildlife, warranting further research into the causes and consequences of wildlife responses to increasingly human-dominated landscapes.
... These traits can make them susceptible to habituation and food conditioning [27,28], learned behaviors that form when the association between developed areas and risk is reduced and an animal equates human development with food [21,29,30]. Naive bears presumably enter developed areas for the first time during exploratory movements [17,30,31], then, over repeated visits, they become habituated and/or food-conditioned [5,29]. The degree of a bear's food conditioning is influenced by the availability of natural and anthropogenic food sources [32], tolerance of humans [29], and reproductive status [33], with highly food-conditioned bears more likely to have negative human interactions (e.g., cause property damage and injuries to humans [32,34]). ...
... Expanding human development into more natural areas is expected to continue, increasing the likelihood of human-bear interactions, and exacerbating both real and perceived risks [31]. The complexity of the issues surrounding human-bear interactions requires wildlife researchers and managers to develop a more comprehensive understanding of the factors shaping bears' diet, movement, and behaviors [31]. ...
... Expanding human development into more natural areas is expected to continue, increasing the likelihood of human-bear interactions, and exacerbating both real and perceived risks [31]. The complexity of the issues surrounding human-bear interactions requires wildlife researchers and managers to develop a more comprehensive understanding of the factors shaping bears' diet, movement, and behaviors [31]. Kirby et al. [64] reported that each 1‰ increase in δ 13 C increased the likelihood that a bear would cause human-bear conflicts by 60%. ...
Article
Full-text available
Increasing human–bear conflicts are a growing concern, and managers often assume bears in developed areas are food-conditioned. We examined the relationship between human–bear conflicts and food conditioning by analyzing isotopic values of hair from black bears (Ursus americanus floridanus) involved in research (n = 34) and conflicts (n = 45). We separated research bears into wild and developed subgroups based on the impervious surface within their home ranges and separated conflict bears based on observations of human food consumption (anthropogenic = observations; management = no observations). We initially assumed wild bears were not food conditioned and anthropogenic bears were. However, using isotopic values, we classified 79% of anthropogenic bears and 8% of wild bears as food conditioned. Next, we assigned these bears to the appropriate food conditioned category and used the categorizations as a training set to classify developed and management bears. We estimated that 53% of management bears and 20% of developed bears were food conditioned. Only 60% of bears captured within or using developed areas showed evidence of food conditioning. We also found that δ13C values were a better predictor of anthropogenic foods in a bear’s diet than δ15N values. Our results indicate that bears in developed areas are not necessarily food conditioned and caution against management actions based on limited observations of bear behavior.
... Anthropogenic food attractants are a common source of human-wildlife conflict [1]. Attractants like garbage can appear beneficial as they are predictable, consistent, and spatially aggregated sources of possibly high-caloric food, thus requiring less foraging effort [10]. For potentially dangerous animals like large carnivores, their use of such attractants can provoke management responses that typically involve relocating or destroying the animal [11,12]. ...
... Black bears (Ursus americanus) often occupy urban-wildland interfaces in North America and have been found to change their natural behaviours as a result of human disturbance (including human presence and development) [10,16]. They are a forest-adapted species with generalist diets and can alter their foraging patterns to access new food sources [10,12,17]. ...
... Black bears (Ursus americanus) often occupy urban-wildland interfaces in North America and have been found to change their natural behaviours as a result of human disturbance (including human presence and development) [10,16]. They are a forest-adapted species with generalist diets and can alter their foraging patterns to access new food sources [10,12,17]. In the urban-wildland interface, omnivorous bears may select for anthropogenic over wild food sources [12], preying on livestock and consuming garbage, compost, bird feed, and fruit. ...
Article
Full-text available
The urban-wildland interface is expanding and increasing the risk of human-wildlife conflict. Some wildlife species adapt to or avoid living near people, while others select for anthropogenic resources and are thus more prone to conflict. To promote human-wildlife coexistence, wildlife and land managers need to understand how conflict relates to habitat and resource use in the urban-wildland interface. We investigated black bear (Ursus americanus) habitat use across a gradient of human disturbance in a North American hotspot of human-black bear conflict. We used camera traps to monitor bear activity from July 2018 to July 2019, and compared bear habitat use to environmental and anthropogenic variables and spatiotemporal probabilities of conflict. Bears predominantly used areas of high vegetation productivity and increased their nocturnality near people. Still, bears used more high-conflict areas in summer and autumn, specifically rural lands with ripe crops. Our results suggest that bears are generally modifying their behaviours in the urban-wildland interface through spatial and temporal avoidance of humans, which may facilitate coexistence. However, conflict still occurs, especially in autumn when hyperphagia and peak crop availability attract bears to abundant rural food resources. To improve conflict mitigation practices, we recommend targeting seasonal rural attractants with pre-emptive fruit picking, bear-proof compost containment, and other forms of behavioural deterrence. By combining camera-trap monitoring of a large carnivore along an anthropogenic gradient with conflict mapping, we provide a framework for evidence-based improvements in human-wildlife coexistence.
... Such changes alter the distribution of wildlife and negatively influence biodiversity, with species at higher trophic levels usually affected to a greater degree due to their space and resource needs (Ripple et al. 2014). Along with predator losses, there has been a growing understanding of predators' ability to exist in human-altered environments (Beckmann and Berger 2003). Predators inhabiting modified landscapes are often facilitated by diverse food resources, including carcasses, livestock, rubbish, and anthropogenic foods ( Figure 2; Abay et al. 2011;Ciucci et al. 2020). ...
... Many anthropogenic food sources have consistent locations to which animals repeatedly return (Chilvers and Corkeron 2001; Bino et al. 2010), thereby limiting the amount of time predators spend searching for food (Beckmann and Berger 2003). Sharks and rays that have been provisioned arrive at provisioning sites sooner and return during typical feeding times whether or not provisioning has occurred (Gallagher et al. 2015). ...
... Non-prey resources also influence predator life history. Bears undergo shorter hibernation periods and alter migration in areas with abundant anthropogenic food (Beckmann and Berger 2003;Cozzi et al. 2016). These changes are more frequent when large quantities of concentrated food are available. ...
Article
Full-text available
Rapid and ongoing environmental change is leading to scenarios where marine and terrestrial predators are persisting without prey, either by scavenging or using anthropogenic foods. Despite investigations into the effects of predator presence or absence on prey behavior and ecology, little research has assessed the effect of prey absence on predators. Here, we synthesize research on scavenging and the use of anthropogenic resources by marine and terrestrial predators; hypothesize how the use of these resources may change predator behavior with respect to their social structure, space use, life history, and individual behavioral traits; and illustrate how these changes are likely to have cascading effects through ecosystems. The prevalence of predators persisting without prey will almost certainly change in the future due to altered availability of anthropogenic foods, scavenging opportunities, and natural prey. We discuss areas of needed research and the relevance of our findings to both the conservation and ecology of predators and management of human–wildlife conflict.
... Although adaptations to live in urban settings are not well understood, wildlife that use urban areas generally share common characteristics such as flexible diets (McKinney 2002;Ryan and Partan 2014), smallto medium-sized bodies (Baker and Harris 2007), and flexible activity patterns (Lowry et al. 2013;Lendrum et al. 2017). For instance, red foxes (Vulpes fulva), coyotes (Canis latrans), raccoons (Procyon lotor), opossums (Didelphis virginiana), and striped skunks (Mephitis mephitis) commonly occur in urban areas; some since the beginning of the 20th century (Bateman and Fleming 2012) have flexible diets and circadian patterns (Beckmann and Berger 2003;Riley et al. 2003), and mostly weigh < 10 kg (Baker and Harris 2007). Being omnivorous in urban areas includes eating garden foods, urban rodents and birds, and pets, as well as refuse (Bateman and Fleming 2012). ...
... American black bears (Ursus americanus) are behaviorally flexible omnivores highly adapted to find and secure high-calorie foods and, thus, benefit from a variety of urban resources (Beckmann and Berger 2003;Beckmann and Lackey 2008). Although generally diurnal, black bears exhibit flexible circadian patterns in urban (Baruch-Mordo et al. 2014;Johnson et al. 2015;Zeller et al. 2019) and forested areas (Powell et al. 1997). ...
... Female yearlings at the urban study site weighed about double that of yearlings from the rural sites. We hypothesize that anthropogenic foods provide important calories for urban bears, as has been observed for urban flying foxes in Melbourne, Australia (Williams et al. 2006), urban herring gulls (Larus argentatus) in the Netherlands (van Donk et al. 2019), urban grizzly bears (Ursus arctos) in North America (Coogan and Raubenheimer 2016), and urban black bears in Montana (Beckmann and Berger 2003). Nevertheless, Merkle et al. (2013) concluded that although bears consumed garbage and ornamental fruits from trees, they selected wild foods over garbage when the former were available. ...
Article
Full-text available
Human-dominated landscapes contain fragmented natural land cover interspersed throughout an urban matrix. Animals that occupy human-dominated landscapes often grow and reproduce differently than conspecifics. Female American black bears (Ursus americanus) produce litters for the first time usually at age 4 years; 2-year-olds rarely give birth. We visited winter bear dens and trapped bears in spring and summer to compare the reproductive output and weight of female black bears within the city limits of Asheville, North Carolina, and three forested rural sites in North Carolina and Virginia representative of the undeveloped habitat of Asheville. Urban yearling females weighed nearly double (45.0 kg ± 8.1 [± SD]; n = 36) that of yearling females from the three rural study sites (23.2 ± 8.5 [Pisgah], 23.6 ± 8.3 [Virginia SW], and 23.9 ± 9.7 [Virginia NW]; n = 95). Across all sites, hard mast production during the autumn, when females were cubs, did not affect their weights as yearlings. Seven of 12 (58%) 2-year-old urban bears produced 11 cubs (mean litter size = 1.6 ± 0.8), but no 2-year-old rural females produced cubs. Production of hard mast in the autumn, when females were yearlings, did not influence cub production by 2-year-old female bears at the urban site. We hypothesize that reproduction by 2-year-old bears is linked to the availability of anthropogenic food sources associated with urban environments. To inform population level management decisions, managers and researchers should quantify urban food sources and the effects on black bear life history. If high fecundity allows urban populations to sustain relatively high mortality rates, then urban bear populations may be source populations for surrounding, rural areas. Alternately, if reproduction in urban populations cannot match high time-specific or age-specific urban mortality rates, then urban populations may be sinks for the surrounding areas.
... The eastern portion of the study area was in the rain-shadow of the Sierra Nevada and was more characteristic of the arid Great Basin. Those mountain ranges were characterized by steep topography with high granite peaks and deep canyons, and were separated by desert basins 15-64 km wide that included expanses of sagebrush (Grayson 1993, Beckmann andBerger 2003), which cougars use infrequently (Beckmann and Berger 2003, Andreasen et al. 2012, Andreasen 2014. Thus, cougar habitat in the Great Basin is insular and naturally fragmented (Grayson 1993, Beckmann and Berger 2003, Andreasen 2014. ...
... The eastern portion of the study area was in the rain-shadow of the Sierra Nevada and was more characteristic of the arid Great Basin. Those mountain ranges were characterized by steep topography with high granite peaks and deep canyons, and were separated by desert basins 15-64 km wide that included expanses of sagebrush (Grayson 1993, Beckmann andBerger 2003), which cougars use infrequently (Beckmann and Berger 2003, Andreasen et al. 2012, Andreasen 2014. Thus, cougar habitat in the Great Basin is insular and naturally fragmented (Grayson 1993, Beckmann and Berger 2003, Andreasen 2014. ...
... Those mountain ranges were characterized by steep topography with high granite peaks and deep canyons, and were separated by desert basins 15-64 km wide that included expanses of sagebrush (Grayson 1993, Beckmann andBerger 2003), which cougars use infrequently (Beckmann and Berger 2003, Andreasen et al. 2012, Andreasen 2014. Thus, cougar habitat in the Great Basin is insular and naturally fragmented (Grayson 1993, Beckmann and Berger 2003, Andreasen 2014. Dominant vegetation in Great Basin mountain ranges included sagebrush shrublands on the lower slopes, followed by pinyon-juniper woodlands and mountain sagebrush communities as elevation increased (Grayson 2011). ...
Article
Full-text available
Natural controls on the distribution, abundance, or growth rates of exotic species are a desirable mode of intervention because of lower costs compared to anthropogenic controls and greater social acceptance. In the Great Basin, cougars (Puma concolor) are the most widely distributed carnivore capable of killing large ungulate prey. Populations of feral horses (Equus ferus) are widely distributed throughout the Great Basin and can grow at rates up to 20%/year. Although cougars exhibit distributional overlap with horses, it has been assumed that predation is minimal because of differences in habitat use and body‐size limitations. To evaluate this hypothesis, we monitored the diets of 21 global positioning system (GPS)‐collared cougars in the western Great Basin (5 males, 8 females) and eastern Sierra Nevada (2 males, 6 females) from 2009–2012. We investigated 1,310 potential kill sites and located prey remains of 820 predation events. We compared prey composition and kill rates of cougars inhabiting the Sierra Nevada and Great Basin, and among male and female cougars across seasons. We used generalized linear mixed models (GLMMs) to examine the effects of prey availability and habitat characteristics on the probability of predation on horses by cougars. Mule deer (Odocoileus hemionus) comprised 91% of prey items killed on the Sierra Nevada reference site but only comprised 29% of prey items in the Great Basin study area. Average annual kill rates for deer differed between the Sierra Nevada ( = 0.85 deer/week, range = 0.44–1.3) and Great Basin ( = 0.21 deer/week, range = 0.00–0.43). Diets of cougars in the Great Basin were composed predominantly of horses (59.6%, n = 460 prey items; 13 individuals). Ten cougars regularly consumed horses, and horses were the most abundant prey in the diet of 8 additional individuals in the Great Basin. Cougars on average killed 0.38 horses/week in the Great Basin (range=0.00–0.94 horses/week). Differences in predation on horses between the sexes of cougars were striking; Great Basin females incorporated more horses across all age classes year‐round, whereas male cougars tended to exploit neonatal young during spring and summer before switching to deer during winter. Within GLMM models, the probability of predation on horses compared to other prey species increased with elevation, horse density, and decreasing density of mule deer on the landscape, and was more likely to occur in sagebrush (Artemesia spp.) than in pinyon (Pinus monophylla)–juniper (Juniperus osteosperma) forests. Behavior of individual cougars accounted for more than a third of the variation explained by our top models predicting predation on horses in the Great Basin. At landscape scales, cougar predation is unlikely to limit the growth of feral horse populations. In the Great Basin ecosystem, however, cougars of both sexes successfully preyed on horses of all age classes. Moreover, some reproductive, female cougars were almost entirely dependent on feral horses year‐round. Taken together, our data suggest that cougars may be an effective predator of feral horses, and that some of our previous assumptions about this relationship should be reevaluated and integrated into management and planning. © 2021 The Wildlife Society. In the Great Basin ecosystem, cougars of both sexes successfully preyed on horses of all age classes with some adult females almost entirely dependent on this resource year‐round. Our data suggest that cougars may be an effective predator of feral horses, and that some of the previous assumptions about this relationship should be reevaluated and integrated into management and planning.
... Human disturbance is very high in urban areas owing to high residential populations. Interestingly, certain urban wildlife do not use forests as a cover to avoid human disturbance and almost always have 100% of their location points within urban areas (e.g., American black bear Ursus americanus; Beckmann and Berger 2003). Why does this phenomenon of inhabitation in areas of human disturbances differ between mammals that cause crop damage and urban mammals? ...
... The simplest theory that explains how the distribution of animals is governed is ideal free distribution (IFD) (Fretwell 1969). This theory assumes that all animals are "ideal," i.e., they have perfect information about the quality of the patches, and "free" implying that animals move freely between habitats and assort themselves in proportion to resource availability without incurring a cost (Beckmann and Berger 2003;van der Hammen et al. 2012). Therefore, it is expected that the distribution is optimized to a point where no individual can increase their fitness by moving to another patch (van der Hammen et al. 2012). ...
Article
Full-text available
Crop damage caused by mammals is not uniformly distributed and is more localized near the forest; this damage distribution differs from that of insect pests. Species that cause damage are often forest inhabitants and hence the damage sites are also biased toward the forest edge. However, these species do not necessarily use forests as their home ranges for cover or shelter, but may be entirely urban (e.g., urban bears). Forest vegetation cannot be considered essential for these species, as this contradicts the behavior of animals that use urbanized areas only. Our review illustrates why crop damage is uneven, localized at forest edges, and less likely to occur on farmlands away from forests in terms of population density, food availability, personality, habituation, and human behavior. This review reveals the role and risk perception of human disturbances. If risk of farmland is perceived to be greater than the true risk, mammals prefer farmlands near forests with low degrees of human disturbances (perceptual trap). The current damage distribution is a result of this perceptual trap because hunting pressures are not always higher in farmlands than in forests.
... These are distributed in the states of Sonora, Chihuahua, Coahuila, Nuevo Leon, Tamaulipas, Durango, Zacatecas, San Luis Potosi, Sinaloa, Nayarit and Aguascalientes [1,[4][5][6] (see S1 Fig, available online). There have been reports of population reduction due to increased anthropogenic pressures on wildlife, habitat destruction (e.g., agriculture and livestock production), loss of natural prey/foods and rapid urbanization [4,[7][8][9]. ...
... We compared bear groups to examine differences by age. Studies in horses and humans showed significant differences between different ages [9,38]. Similarly, we found here a significant difference in alanine (Ala), glycine (Gly) and acetylcarnitine (C2). ...
Article
Full-text available
Introduction Ursus americanus Pallas 1780 is the largest carnivore and the only ursid in Mexico. It is considered an endangered species in the country because its distribution and population have been reduced by up to 80% because of habitat loss or furtive hunting. These problems can lead to a diet change, which could result in metabolic disorders, such as fatty acid β-oxidation defects or organic acid metabolism disorders. In our study, a free amino acid and acylcarnitine profile was characterized. Methods Peripheral blood samples were drawn from nine free-ranging black bears in a period of five months, from June to October of 2019 in Northeastern Mexico, and 12 amino acids and 30 acylcarnitines were determined and quantified. Age differences were observed in the samples through ANOVA and post-hoc Tukey test. Results Only three metabolites showed a significant difference with age: alanine (Ala) [cubs vs juvenile], free-carnitine (C0) [juvenile vs cubs] and acetylcarnitine (C2) [cubs vs adults and juvenile vs cubs]. Conclusion Metabolites with variability due to age were identified, making them potential biomarkers to monitor metabolic status as early diagnosis in endangered species. This is the first study of black bear amino acid and acylcarnitine profiles, and the values found could be used as reference for free amino acid and acylcarnitine concentrations in further studies of the species.
... Urban habitats often provide an abundance of food, water and shelters (Adams et al., 2006), and urban mammals can be expected to adapt their behaviour accordingly. Urban red foxes, Vulpes vulpes, and European badgers, Meles meles, are able to fulfil their energetic needs by foraging during shorter periods and over shorter distances than rural ones (Harris, 1982;Doncaster & Macdonald 1997;Davison et al., 2009), while American black bears, Ursus americanus, are 36% less active in urban than in wildland areas (Beckmann & Berger, 2003). Furthermore, territory sizes in urban areas are typically smaller than in rural areas (Davison et al., 2009;Herr et al., 2009a) and so presumably require less effort to be patrolled. ...
... For example, bobcats, Lynx rufus, and coyotes, Canis latrans, have been shown to reduce their diurnal activity in areas with higher human activity, suggesting behavioural avoidance of humans (McClennen et al., 2001;Tigas et al., 2002;Riley et al., 2003;Wang et al., 2015;Smith et al., 2018). Black bears living in the urban-wildland interface have shown comparable activity shifts (Beckmann & Berger, 2003). Similarly, urban red foxes show strong evidence of temporal adaptation of their movement patterns to avoid human disturbance, such as simple human presence (Gloor, 2002;Díaz-Ruiz et al., 2016) or even very low levels of road traffic (Baker et al., 2007). ...
Chapter
In Europe, the stone marten, Martes foina , is one of the main carnivore species to inhabit urban areas. While these environments are generally resource rich, they also present a range of anthropogenic stresses, such as human persecution or road traffic, which have the potential to induce behavioural responses in urban wildlife. We radio‐tracked 12 stone martens in two towns in Luxembourg in order to determine how their activity (duration of the principal activity period, nightly activity duration) and movement (nightly movement distance, movement speed, nightly range) patterns were adapted to this environment. Stone martens displayed a more strictly nocturnal lifestyle than was known from studies on this species in more rural environments. We argue this to be a behavioural adaptation to reduce the rate of potential contact with humans. In fact, during long winter nights, emergence from dens took place long after sunset and return to dens intervened mostly before traffic picked up in the mornings. Furthermore, during long nights, marten peak activity was shifted to those parts of the night when human activity was at its lowest. On the other hand, stone martens were active during the entire dark period during short summer nights. Despite presumably higher resource availability and somewhat smaller territories compared to other studies, stone marten activity duration and movement distances were similar to those recorded in forest or rural populations elsewhere. Interestingly spring mobility was more pronounced in females than would be expected. We discuss these results in the context of territorial behaviour which, in urban areas, is likely to be driven by factors such as increased perceived intruder pressure.
... Habitat modifications by humans cause changes to resource availability, which may alter the tradeoff between acquiring resources and avoiding conflict, which in turn, can be reflected in an animal's movement behavior (Allen and Singh, 2016;Doherty and Driscoll, 2018). Examples include reduced search and commute time, allowing animals to travel less to find food (Fleming and Bateman, 2018;Tucker et al., 2018) and acquire energy faster (Beckmann and Berger, 2003), or increased foraging within residential development areas when natural food is scant (Johnson et al., 2020). ...
... Large-carnivore persecution may be the result of damage to humans, livestock, or property, or just due to the belief that carnivores can cause such damage (Støen et al., 2015;Bleyhl et al., 2021) even if it doesn't match any actual degree of risk (Dickman, 2010;Ordiz et al., 2019). A carnivore's attraction to predictable anthropogenic food resources, such as anthropogenic waste, domestic animals, roadkill, and deliberate feeding in human-dominated landscapes (Bateman and Fleming, 2012;Dubois and Fraser, 2013;Fleming and Bateman, 2018) may result in a loss of fear, increased tolerance to human presence, and even aggressive behaviors (Orams, 2002;Beckmann and Berger, 2003;Dubois and Fraser, 2013;Elfström et al., 2014). All of these behavioral changes may increase the perceived conflict between carnivores and humans and can further intensify the persecution of carnivores (Støen et al., 2015;Bleyhl et al., 2021). ...
Article
Full-text available
Large-carnivore populations have experienced significant declines in the past centuries in extended parts of the world. Habitat loss, fragmentation, and depletion of natural resources are some of the main causes of this decline. Consequently, behavioral flexibility, enabling the exploitation of anthropogenic food resources in highly disturbed human-dominated landscapes, is becoming critical for the survival of large carnivores. These behavioral changes increase the potential for human-large carnivore conflict and can further intensify carnivore persecution. Here, we examine how land cover types (representing a gradient of anthropogenic disturbance) alter the behavior of striped hyenas (Hyaena hyaena) in a human-dominated landscape in Israel, and whether differences in life history between males and females affect their reaction to such disturbances and consequently their level of exposure to humans. We used a Hidden Markov Model on GPS-tracking data for seven striped hyenas to segment individual-night trajectories into behavioral states (resting, searching, and traveling). We then used multinomial logistic regression to model hyenas’ behavioral state as a function of the interaction between land cover and sex. Females traveled less than males both in terms of average distance traveled per hour, per night, and nightly net displacement. Most steps were classified as “searching” for females and as “traveling” for males. Female hyenas spent a higher proportion of time in human-dominated areas and a lower proportion in natural areas compared to males, and they were also more likely to be found close to settlements than males. Females changed their time allocation between natural and human-dominated areas, spending more time resting than traveling in natural areas but not in human-dominated ones; males spent more time searching than resting in human-dominated areas but were equally likely to rest or search in natural ones. The differences in life history between male and female hyenas may reflect different motivations for space use as a means to optimize fitness, which affects their exposure to humans and therefore their potential involvement in human-hyenas conflict. Understanding the mechanisms that lead to behavioral change in response to human disturbance is important for adaptive management and promoting human large-carnivores co-existence in general.
... The high degree of diurnality among large carnivores evident in our study sites contrasts with reports from other forests, as in Madagascar and North America where carnivores were largely active at night 32,33 . These previous studies focused on more anthropogenic landscapes, where carnivores appear to avoid interacting with humans by becoming more nocturnal [32][33][34] . ...
... The high degree of diurnality among large carnivores evident in our study sites contrasts with reports from other forests, as in Madagascar and North America where carnivores were largely active at night 32,33 . These previous studies focused on more anthropogenic landscapes, where carnivores appear to avoid interacting with humans by becoming more nocturnal [32][33][34] . Our sites are within protected areas and therefore suffer lower human impacts than elsewhere and may permit greater diurnality. ...
Preprint
Full-text available
Most animals follow distinct daily activity patterns reflecting their adaptations1, requirements, and interactions2-4. Specific communities provide specific opportunities and constraints to their members that further shape these patterns3,4. Here, we ask whether community-level diel activity patterns among long-separated biogeographic regions differ or converge and whether the resulting patterns indicate top-down (predation risk) or bottom-up processes (prey availability)? We estimated the diel activity of ground-dwelling and scansorial mammals in 16 protected areas across the tropics, using an extensive network of camera traps, and examined the relationship to body mass and trophic guild. We found that mammalian guilds exhibited consistent diel activity patterns across regions, indicating similar responses to similar evolutionary and ecological opportunities and constraints. Larger herbivores tended to be more nocturnal than smaller herbivores, whereas carnivores and omnivores showed the opposite pattern. Insectivores were exceptions, revealing regional differences in which larger insectivorous species were more nocturnal than smaller ones in the Afrotropical and Indo-Malayan regions, while the pattern reversed in the Neotropics. The consistent contrast between predators and prey suggests that diel activity within these communities is primarily determined by large predators and associated risk of predation.
... Moreover, habituation to consuming human, especially discarded, foods is a significant threat to wild black bear health. Not only are bears then more likely to be euthanized due to human-bear conflicts, but they are also more likely to be over-or under-conditioned, have dental disease, or have chronic nutritional deficiencies [41,42]. Malnutrition of young bears may also occur during times of mast failure in which there is a seasonal decrease in natural food sources, causing them to starve or search out human-related foods. ...
Article
Full-text available
Severe musculoskeletal disease characterized by marked joint laxity was the cause of euthanasia in two wild juvenile American black bears (Ursus americanus) admitted to a rehabilitation facility in eastern Tennessee in 2023. Previously, almost all reported musculoskeletal diseases in this population were of traumatic etiology, even in malnourished yearlings. Case 1 was an orphaned 11-month-old male cub exhibiting disproportionate dwarfism, progressive immobility, and joint laxity. Necropsy findings suggested either chondrodysplasia or rickets, and imaging findings supported a skeletal dysplasia. Case 2 was a 14-month-old emaciated male yearling exhibiting joint laxity and immobility. Necropsy findings showed osteoporosis and serous atrophy of fat, and imaging findings were inconsistent with a skeletal dysplasia. Both cases were clinically inconsistent with rickets based on normal calcium, phosphorous, and parathyroid hormone concentrations; however, Case 1 had hypovitaminosis D (9 nmol/L) compared to healthy juvenile black bears. We hypothesize that Case 1 had a genetic chondrodysplasia while the osteoporosis of Case 2 was due to chronic malnutrition. The goal of this case report is to inform wildlife agencies and facilities to monitor for similar, non-trauma-related debilitating musculoskeletal disease in free-ranging bears and evaluate cases that allow us to further understand the disease processes involved.
... Wildlife responses to human activity may include fine-scale behavioral shifts for more adaptable species (e.g., altering diel activities; Gaynor et al., 2018;Nickel et al., 2020) or effective habitat loss for more sensitive species (Coppes, Ehrlacher, et al., 2017;Heinemeyer et al., 2019). Some species may also associate with humans as a "shield" from predators (Berger, 2007;Procko et al., 2022;Sarmento & Berger, 2017), or due to attraction to agriculture or trash (Beckmann & Berger, 2003;Zinn et al., 2008), demonstrating that wildlife responses to human activity can manifest as complex systems of "pushes" and "pulls." Additionally, recreation may impact reproductive success (Phillips & Alldredge, 2000), which could have population-level consequences. ...
Article
Full-text available
Recreation is known to impact wildlife by displacing and sometimes contributing to the extirpation of sensitive species, underscoring a need for policies that balance wildlife and recreation. This is especially pressing when Indigenous rights necessitate ecological integrity and sustainable populations of wildlife throughout traditional territories. In the Cascade Mountain Range of Washington, USA, Indigenous harvest of elk (Cervus canadensis) is declining, concurrent with increases in recreation. Yet, the nature and magnitude of the effects of recreation on elk are unknown, which prevents land managers from developing informed policies regarding recreation and wildlife management. Here, we use camera traps alongside visitation models that incorporate geolocated social media to quantify the impacts of recreation on elk in western Washington. Random forest models show elk detection rates are relatively constant at low levels of recreation (0–11 people/day), but decrease by over 41% when recreation increases from 12 to 22 people/day. Activity overlap analysis also revealed a shift toward increased evening activity by elk at cameras with higher‐than‐average recreation (∆ = 0.70, 95% CI = 0.61–0.88; χ² = 7.79, p = 0.02). Generalized additive modeling confirms that elk are more crepuscular or nocturnal at camera locations with more than 10 hiker detections per day. We compare methods for estimating recreation, showing model‐based estimates are more informative than camera‐based estimates. This indicates that recreational intensity along and in the immediate vicinity of trails may be a better predictor of impacts on wildlife than camera‐based estimates that quantify recreational intensity at specific locations along trails. We stress the importance of examining the impacts of recreation on wildlife across multiple spatiotemporal scales and underscore how novel approaches can provide land managers valuable tools to develop management strategies that balance recreation and wildlife. We hope that our work can also serve as a strong example of collaboration between universities, state agencies, and sovereign Indigenous nations toward the broader goal of mitigating the negative impacts of recreation on wildlife.
... In northern Pakistan and the autonomous state of Azad and Jammu Kashmir, bears frequently inhabit dense temperate forests at altitudes ranging from 1,500 m to 3,000 m above sea level, though they also intermittently occupy human-modified habitats at lower altitudes (Abbas et al. 2015;Awan et al. 2021;Ahmad et al. 2022). In areas where bears are heavily disturbed by human activities or rely on human food sources, they exhibit more nocturnal behavior and stay close to anthropogenic features (Ayres et al. 1986;Beckmann and Berger 2003;Matthews et al. 2006: Schwartz et al. 2010. ...
Article
Full-text available
Ecological research focused on Asiatic black bears (Ursus thibetanus) sympatric interactions is critical for understanding not only species coexistence, but also for devising effective conservation strategies. We studied the temporal overlap and co-occurrence patterns of the Asiatic black bear and ten of its sympatric species. Asiatic black bears and Asiatic jackals exhibited bimodal diel activity patterns, with activity peaks occurring during dusk and the night. The diel activity pattern of Asiatic black bear was significantly distinct from its sympatric species (P < 0.001). We found the highest temporal overlap of Asiatic black bear with red fox (Δ4 = 0.78, 95% CI = 0.68 – 0.89) followed by stone marten (Δ1 = 0.76. 95% CI = 0.64 – 0.87) and Indian crested porcupine (Δ1 = 0.74, 95% CI = 0.62 – 0.85). The lowest temporal overlap of the Asiatic black bear was recorded with rhesus monkey (Δ1 = 0.38, 95% CI = 0.27 – 0.50). Asiatic black bears avoided human activity times and had little activity overlap (Δ4 = 0.29, 95% CI = 0.19 – 0.39). Asiatic black bear was more likely to co-occur (Pgt < 0.05) with six other species than what we observed. This study's comprehensive insights into the adaptable behavior of Asiatic black bears, including their spatial and temporal overlap with sympatric species and the influence of environmental variables like forest cover and altitude, provide crucial guidance for wildlife managers and conservationists in designing effective conservation measures to protect habitat and mitigate human-wildlife conflicts, thereby ensuring the sustainable management and conservation of Asiatic black bears and the broader biodiversity of their temperate habitats.
... Our study shows that black bears were more active during midnight (9 PM-3 AM) and least active in the daytime (6 AM-6 PM), which aligns with the study of [33] in DHR, Nepal. On the contrary, several studies [34][35][36][37][38][39] have indicated that black bear movement patterns, with most of the activity occurring during daylight hours, peak notably in the morning and evening and are lowest at night [35][36][37][38]. ...
Article
Full-text available
Simple Summary This research paper presents a comprehensive study of the patterns of conflicts between humans and Asiatic black bears (Ursus thibetanus) in the Guthichaur rural municipality, Jumla, Nepal. Through semi-structured interviews with villagers, focus group discussions, and key informant interviews, this study explores the extent of crop damage, livestock depredation, and human injuries caused by black bears from 2009 to 2019. It was found that crop damage was the most significant form of conflict, followed by livestock depredation and human casualties. This study identifies anthropogenic activities, such as human encroachment into bear habitats and agricultural practices near forests, as primary drivers of these conflicts. Importantly, this research proposes measures to mitigate these conflicts, including initiating compensation schemes for losses, establishing electric fences for crop protection, and launching educational programs. These recommendations, rooted in local practices and conservation efforts, show promise for managing conflicts in regions facing similar challenges with black bears. This paper fills a critical gap in understanding the dynamics of human–bear conflicts in Nepal, contributing valuable insights into wildlife management and conservation strategies. Its findings are significant for researchers, policymakers, and conservationists aiming to develop sustainable solutions for human–wildlife coexistence. Abstract Our study assessed patterns of Asiatic black bear (Ursus thibetanus)–human conflicts within the Guthichaur rural municipality, Jumla, Nepal. Through semi-structured interviews with villagers, focus group discussions (FGDs), and key informant interviews (KIIs), we gathered black bear–human conflict information from 2009 to 2019. We identified three primary types of black bear–human interactions: crop damage, livestock depredation, and human injuries. Of these, crop damage (77.03%) emerged as the most prevalent issue. Notably, peak occurrences were observed during autumn (September–October) typically between 9 PM and 3 AM. Livestock depredations were more frequent during nighttime in April–August, with cows/ox (70.12%) being the most depredated animal. Our data also revealed five recorded cases of black bear attacks on humans, which transpired from September to October, primarily in farmland areas in varying years. Despite a prevailing negative perception of bears, a notable level of support exists for their conservation efforts among local communities. Furthermore, these conflicts could be mitigated by reinforcing indigenous crop protection methods and implementing targeted mitigation strategies, as observed in other regions with successful black bear–human interaction management.
... Where available, anthropogenic resource subsidies are heavily exploited by black bears in their Nevada range (Beckmann & Berger, 2003b;van Manen et al., 2020), mostly in the more populated urban and exurban areas directly at the interface of the Sierra Nevada and the Great Basin (e.g., Reno, Carson City; Figure 2). ...
Article
Full-text available
Investigating spatial patterns of animal occupancy and reproduction in peripheral populations can provide insight into factors that form species range boundaries. Following historical extirpation, American black bears ( Ursus americanus ) recolonized the western Great Basin in Nevada from the Sierra Nevada during the late 1900s. This range expansion, however, has not continued further into the Great Basin despite the presence of additional habitat. We aimed to quantify whether reduced reproduction toward the range edge contributes to this range boundary. We analyzed black bear detections from 100 camera traps deployed across black bear distribution in western Nevada using a multistate occupancy model that quantified the probability of occupancy and reproduction (i.e., female bears with cubs occupancy) in relation to changes in habitat type and habitat amount toward the range boundary. We detected a strong effect of habitat amount and habitat type on the probability of black bear occupancy and reproduction. At similar levels of landscape‐scale habitat amount (e.g., 50%), estimated probability of occupancy for adult bears in piñon‐juniper woodlands near the range boundary was 0.39, compared to ~1.0 in Sierra Nevada mixed‐conifer forest (i.e., core habitat). Furthermore, estimated probability of cub occupancy, conditional on adult bear occupancy, in landscapes with 50% habitat was 0.32 in Great Basin piñon‐juniper woodlands, compared to 0.92 in Sierra Nevada mixed‐conifer forest. Black bear range in the western Great Basin conforms to the center–periphery hypothesis, with piñon‐juniper woodland at the range edge supporting ecologically marginal habitat for the species compared to habitat in the Sierra Nevada. Further geographic expansion of black bears in the Great Basin may be limited by lower occupancy of reproducing females in piñon‐juniper woodland. Center–periphery range dynamics may be common in large carnivore species, as their dispersal ability allows them to colonize low‐quality habitat near range edges.
... The potential rewards of foraging within urban and agricultural areas often comes with increased risk of conflict with humans (Abrahms et al., 2023;Beckmann & Berger, 2003) and mortality (Olson et al., 2015). Movement within these landscapes not only requires wildlife to avoid direct human presence and barriers to movement (e.g., fences, roadways, buildings), they must also navigate under ambient conditions for which most did not evolvehigh levels of sensory pollution (e.g., anthropogenic light, noise; Barber et al., 2010). ...
... Comparatively, black bears were recorded (non-scavenging observation) at only one suburban site. While black bears are known to subsist in suburban areas globally (Beckmann and Berger, 2003;Oka et al., 2004), we suspect that the majority of black bears within our study area occur in the surrounding rural landscape rather than within city limits due to recent productive hard mast years (Georgia Department of Natural Resources, 2021). Black bear space use and activity patterns depend on natural food availability (Baruch-Mordo et al., 2014), and during productive food years bears are less likely to use higher human density areas (Lewis et al., 2015). ...
... (Kettel et al. 2018), Stephanoaetus coronatus (Muller et al. 2020)), monkeys (Chlorocebus pygerythrus (Patterson et al. 2019, Thatcher et al. 2019), bears (Urus spp. (Beckmann & Berger 2003, Bateman & Fleming 2012) and wolves and coyotes (Lupus spp. (Bateman & Fleming 2012, Poessel et al. 2016). ...
Article
Full-text available
Traditional classifications of vertebrates’ responses to urbanization fail to capture the behaviour of those that rely on both urban and wildland resources for population persistence. Here, we use the wood stork ( Mycteria americana ), a species that makes daily foraging trips up to 74 km away from its nest, as an example of a previously unrecognized response to urbanization. We monitored nests and sampled diets at stork colonies in south Florida (USA) during 2014–2020 to investigate how storks use urban habitats. We found that urban development now comprises up to 51.6% of the land cover within the 30-km core foraging area surrounding colonies and that storks access alternative prey types within these urban areas. Our results also showed that urban-nesting storks outperformed wildland-nesting storks when the hydrological condition of the wetlands was suboptimal for foraging. Though storks still require healthy wetlands for population persistence, urban habitat benefitted storks when hydrological patterns were not ideal for prey production in wildlands. This ‘commuter’ response to urbanization, whereby individuals opt to utilize both urban and wildland resources within short time periods, may apply to other vertebrates with large home ranges.
... Poachers and illegal traders often operate in protected areas, encroaching upon critical bear habitats and disturbing the delicate ecological balance (Sathyakumar, 2001). The loss of habitat due to human encroachment is another significant factor contributing to the decline in black bear populations (Ahmad et al., 2022;Beckmann & Berger, 2003;Goursi et al., 2021). As human populations expand, urbanization, deforestation, and industrial development encroach upon the once undisturbed territories of black bears, leading to habitat fragmentation and degradation (Ahmadzadeh et al., 2008). ...
Article
Full-text available
Climate and land use changes are increasingly recognized as major threats to global biodiversity, with significant impacts on wildlife populations and ecosystems worldwide. The study of how climate and land use changes impact wildlife is of paramount importance for advancing our understanding of ecological processes in the face of global environmental change, informing conservation planning and management, and identifying the mechanisms and thresholds that underlie species' responses to shifting climatic conditions. The Asiatic black bear (Ursus thibetanus) is a prominent umbrella species in a biodiversity hotspot in Southwestern China, and its conservation is vital for safeguarding sympatric species. However, the extent to which this species' habitat may respond to global climate and land use changes is poorly understood, underscoring the need for further investigation. Our goal was to anticipate the potential impacts of upcoming climate and land use changes on the distribution and dispersal patterns of the Asiatic black bear in the Sichuan-Chongqing Region. We used MaxEnt modeling to evaluate habitat vulnerability using three General Circulation Models (GCMs) and three scenarios of climate and land use changes. Subsequently, we used Circuit Theory to identify prospective dispersal paths. Our results revealed that the current area of suitable habitat for the Asiatic black bear was 225,609.59 km2 (comprising 39.69% of the total study area), but was expected to decrease by -53.1%, -49.48%, and -28.55% under RCP2.6, RCP4.5, and RCP8.5 projection scenarios, respectively. Across all three GCMs, the distribution areas and dispersal paths of the Asiatic black bear were projected to shift to higher altitudes and constrict by the 2070s. Furthermore, the results indicated that the density of dispersal paths would decrease, while the resistance to dispersal would increase across the study area. In order to protect the Asiatic black bear, it is essential to prioritize the protection of climate refugia and dispersal paths. Our findings provide a sound scientific foundation for the allocation of such protected areas in the Sichuan-Chongqing Region that are both effective and adaptive in the face of ongoing global climate and land use changes.
... For example, when wildlife includes human-derived food in their diet, their behavioral ecology and life histories are often altered (Fehlmann et al., 2021;Schell et al., 2021;Wilson et al., 2020). Because crops and livestock are predictable and abundant in space, easy to harvest/capture, process, and digest (Fehlmann et al., 2021), this can induce measurable shifts in activity budgets (Altmann & Muruthi, 1988;Enners et al., 2018;Isaksson et al., 2016), home ranges (Belton et al., 2016;Reher et al., 2016) and population dynamics (Beckmann & Berger, 2003;Chiyo et al., 2011). Choosing methods to mitigate negative interactions between people and wildlife requires, at minimum, an understanding of the causes, consequences, and history of these interactions (Hayward & Kerley, 2009;Ogada et al., 2003;Snijders et al., 2019). ...
Article
Full-text available
Abstract Understanding the behavioral ecology of wildlife that experiences negative interactions with humans and the outcome of any wildlife management intervention is essential. In the Cape Peninsula, South Africa, chacma baboons (Papio ursinus) search for anthropogenic food sources in both urban and agricultural areas. In response, the city of Cape Town and private farmers employ “rangers” to keep baboons within the Table Mountain National Park. In this study, we investigated the success of rangers' intervention in keeping baboons in their natural habitat. Based on our findings in year one, we recommended adjustments to the rangers' management strategy in year two. We recommended improved consensus of actions toward baboons (that is, when/where to herd them), and the construction of a baboon‐proof fence around one of the farms that provided a corridor to urban areas. During the 2 months following recommendations, these interventions combined resulted in a significant reduction in the time baboons spent in both urban and agricultural land. Our case study illustrates the importance of integrating research findings into ongoing management actions to improve both human livelihoods and baboon conservation through an adaptive management framework. We expect similar approaches to be beneficial in a wide range of species and contexts.
... delineate areas where bears have been documented. Bears are wide-ranging animals that can travel far from suitable bear habitat, especially during dispersal (Maehr et al. 1988) or drought years (McCown et al. 2004) and may forage in urban areas when human-sourced foods are available (Beckmann and Berger 2003, Merkle et al. 2013, Murphy et al. 2017b, Lackey et al. 2018. Compared to the SDM created by Poor et al. (2020) to represent potential bear habitat, our contemporary bear range contained more land area, including areas their model considered nonhabitat. ...
Article
American black bears ( Ursus americanus ) in Florida have increased in abundance from historically low numbers and currently number >4,000 across 7 subpopulations. Biologists monitor the range of black bears to track their recovery for conservation and management efforts. We estimated geographic range of black bears in Florida for historical (2001–2010) and contemporary (2011–2020) periods using 12 sources of occurrence data collected from wildlife professionals and the public. We reduced data sets by subsampling protocols to account for localized spatiotemporal biases and for possible differences in sampling effort from increases in the human population between modeling periods. We developed models at 2 levels: a generalized boundary (range extent) and a more detailed delineation (occupied range). We developed range extent using a concave hull model and occupied range using kernel density estimation with a corresponding 97.5% isopleth. Between modeling periods, range extent increased by 13.4% and occupied range increased by 11.3%, with both range levels expanding and contracting in certain areas. The ranges indicated improved connectivity among bear subpopulations. We also produced a range map for research, management, and public use built upon contemporary data that partitioned the state into 4 levels representing the relative frequency of bear use (frequent, common, occasional, and rare). Range map levels at the occupied range, and especially frequent use areas, help focus bear research efforts (e.g., placement of hair corrals), management efforts (e.g., assess varying levels of risk to the public of bear conflicts), and conservation efforts (e.g., focusing habitat protection in areas with high use by bears).
... Although black bears are a charismatic species that provide several ecosystem services (Garshelis 1990, Stowell and Willging 1992, Miller et al. 1998, Moll et al. 2021, expanding black bear populations have also resulted in increased conflict with humans (Spencer et al. 2007, Don Carlos et al. 2009, Lackey 2010, Mazur 2010. In Nevada, the number of private citizen complaints and vehicle-black bear collisions increased by 10-and 17-fold, respectively, between 1990 and the early 2000s as black bears recolonized western Nevada (Beckmann and Berger 2003a), consistent with trends across North America (Gore et al. 2005, Siemer et al. 2007, Spencer et al. 2007. In response to this growing population, both geographically and numerically, Nevada's first black bear hunting season was initiated in 2011 (Lackey et al. 2013). ...
Article
In the first 2 decades of the twenty‐first century, American black bear ( Ursus americanus ) populations rebounded with range expansions into areas where the species was previously extirpated. While there are a number of factors that limit range expansion, habitat quality and availability are among the most important. Such factors may be particularly important in western Nevada, USA, at the transition zone of the Sierra Nevada and the Great Basin Desert. We deployed a multi‐faceted data collection system including motion‐sensitive cameras, noninvasive hair sampling and genotyping, and global positioning system (GPS) tracking. We analyzed data using spatial capture‐recapture to estimate population density and dynamic occupancy models to estimate habitat use. Black bear habitat use and density were substantially higher in the Sierra Nevada than the Great Basin Desert and had strong positive relationships with the presence of conifer land cover in the transition zone. The average black bear density was >4 times higher in the mixed‐conifer forests of the Sierra Nevada (12.4 bears/100 km ² ) than in desert mountain ranges with piñon ( Pinus monophylla )‐juniper ( Juniperus spp.) woodland (2.7 bears/100 km ² ). The low‐elevation shrub and grassland portions of the study area had even lower estimated black bear density (0.6 bears/100 km ² ) and probability of use (0.03, 95% CI = 0.00–0.09). Across these spatially variable configurations in black bear density, we estimated the population size to be 418 individuals (95% CI = 239–740). Declining density towards the range edge, coupled with a relatively stable range of black bears in Nevada observed since 2000, suggests that further species range expansion into the western Great Basin may be limited by habitat quality and availability.
... As some black bears adapt to the use of exurban and even urban settings (Beckmann and Berger 2003a, b;Gould et al. 2021), incidents of conflict between humans and black bears are on the rise in the region (Humm and Clark 2021). Whereas conflicts between humans and bears have long inspired research into their underlying causes, increasing bear populations and continuing human development of previously natural habitat have given greater urgency to better understand these drivers (Beckmann and Berger 2003a;Braunstein et al. 2020;Kirby et al. 2016). ...
Article
Stable isotope analyses of hair have been used to estimate the consumption of human foods by American black bears (Ursus americanus). Consumption of human foods influences body mass and reproductive success of bears. However, the underlying factors that cause some bears to become conflict bears and resort to consuming human foods as a portion of their diet are not fully understood. We collected hair samples for stable isotope analysis from 51 black bears in Great Smoky Mountains National Park, Tennessee, USA in 2006. We used δ13C values of hairs to determine if the bears were consuming C3-based (natural foods) or C4-based (human foods) diets, and δ15N values, which increase with more meat in the diet, as a further indication of the consumption of human foods. Male bears with the heaviest tooth wear had a combination of higher δ15N and δ13C values, suggesting that they consume human foods to a greater extent than do other black bears. Based on our results, we hypothesize that tooth wear, and thus dental health, may play a role in the consumption of human foods by larger, male bears.
... In addition, it is well known that the behavior of the species may vary depending on the context (i.e. habitat, season, human influence, or prey availability; Beckmann and Berger, 2003;Frey et al., 2020), but is always limited by genetic, anatomic and morphological constraints. Thus, it would be an error to think that the prehistoric behavior of species should be the same as at present. ...
... All individual species, aside from gray fox, had significant relationships with campgrounds, and all of these relationships, aside from black bear, were negatively related. The difference between a large-bodied omnivore (black bears) and the rest of the carnivore species could be due to human food subsidies at campgrounds that draw in opportunistic wildlife, similar to urban food subsidies (Beckmann and Berger 2003;Hopkins et al. 2014). Across the United States, human-wildlife conflict is increasing and often caused by food-conditioned individuals (individuals that have learned to associate humans with food) (Baker and Timm 2017;Mazur 2010). ...
Article
Full-text available
While protected areas are often considered strongholds for wildlife populations, recent research in protected areas has highlighted that both human activity (i.e. presence) and footprint (i.e. structures) can influence wildlife. To determine how human activity and structures affect the spatiotemporal activity of wildlife on the Apostle Islands National Lakeshore, Wisconsin, United States, we monitored the carnivore community for 5 years (2014–2018) using camera traps. We found that lighthouses had a negative impact on carnivore community richness, while historical sites had a positive impact. Responses of individual carnivore species to anthropogenic structures varied depending on structure type, with most of the canids and mustelids exhibiting negative associations with campgrounds. When examining the seasonal effects of human activity and footprint (i.e., when park visitation is relatively high or low), we found that carnivore richness was lower during the high human activity season, suggesting that seasonal variation in human activity influences carnivore activity. We also compared carnivore nocturnality along a gradient of anthropogenic activity, but our results indicate that the carnivore community did not become more nocturnal with increasing anthropogenic activity as expected. However, the carnivore community did display spatial avoidance of current anthropogenic structures, especially campgrounds. Our study indicates that human footprint in the form of structures and seasonal variation in human activity can influence wildlife activity within protected areas. Based on this study, species-specific research that includes multiple representations of potential human effects (i.e., including categories of human footprint and activity) will allow for a more nuanced and cohesive understanding of the impacts of humans on the spatial and temporal distributions of wildlife species.
... Black bears often become inactive 1.5-2 h after sunset, resume activity 0.5-1 h before sunrise, and nap once or twice during the day for a total of 6-8 h of rest per day (Rogers 1987). Bears may become nocturnal to avoid humans (Beckmann et al. 2003), but the need for sleep remains. ...
Article
Full-text available
Sleep is important for memory consolidation and maintaining metabolic homeostasis, but sleep can expose animals to inclement weather and predators. Consequently, selection of sleeping sites is important. We tested three sets of hypotheses related to selection of bed sites by female American black bears (Ursus americanus) at two study sites. During 2009–2013, we outfitted 14 female black bears west of Ely, Minnesota, with Global Positioning System collars that reported bear locations every 10 min. We visited 101 bed sites, each identified from clusters of estimated locations where a bear was on site for ≥4 h on two or more occasions, and recorded bed characteristics, forest composition, canopy closure, and ground cover. We matched each bed site with a control site where we collected the same data. During 1987–1991, we outfitted three female black bears south of Ely with very high-frequency transmitter collars and walked with the bears to collect detailed behavioral data. We used the written data records to identify 62 bed sites where bears slept ≥2 h and where bed characteristics were documented. We matched each bed site with a control site approximately 6 h different when the bear was active. Of the bed sites, 132 were used during night and 31 during day. The two study areas differed in the amount of lowland habitats. At both sites, female bears chose bed sites disproportionately in lowland sites with high canopy cover and next to a tree, especially a white pine. Female bears with cubs selected upland bed sites more often than did females without cubs and also more often selected sites adjacent to a tree with coarse bark, which cubs could climb easily. Distances to roads and houses did not affect selection of bed sites by females either with or without cubs.
... Although we cannot rule out other factors, we speculate that C. chinga reduced daytime activities at CA in response to human-related disturbance, where skunks could be killed by dogs or struck by vehicles (Cunha et al., 2015). This behavioural adaptation has also been reported for other carnivore species (Lucherini et al., 1995;Grinder & Krausman, 2001;Tigas et al., 2002;Beckmann & Berger, 2003;Wang et al., 2015). ...
Chapter
Anthropogenic habitat modification is one of the most serious threats to global biodiversity, and in areas with a high urbanization level and agricultural activities, habitat loss and fragmentation are virtually inevitable. An example of this occurs in the Pampas grassland of Argentina, which is the most densely populated and most degraded region in the country. In this chapter, we explore how the behavioural ecology of the little‐studied Molina's hog‐nosed skunk, Conepatus chinga , has been affected by agricultural activities. We review the recent advances in the ecology and natural history of this mephitid and compare data collected in two grassland areas under different land uses. Information on home range characteristics, movement patterns, habitat use and selection, denning behaviour, and activity patterns was obtained by radio‐tracking skunks in a protected area (7 individuals) and a cropland area (9 individuals). Feeding ecology was also studied through the analysis of faecal samples and estimation of prey abundance. Our results confirmed that C. chinga is mainly a solitary carnivore. The home range size is greater in males than in females, the spatial overlap is largely limited to intersexual dyads, and burrows are not communal. In the Pampas grassland of Argentina, this mephitid is a nocturnal, selective predator of insects, lacking clear sexual dimorphism. That C. chinga selected for habitat patches with natural vegetation and predictable, abundant prey, and that its activity was strictly nocturnal in unprotected croplands, suggests that prey abundance and secure denning sites are important factors affecting its behavioural ecology. We conclude that although C. chinga is somewhat adaptable to human‐modified landscapes, the loss of native grasslands is likely affecting the abundance of its populations in the present‐day Argentine Pampas.
... This finding may be indicative of the situation black bears are forced into in modern day -one of simultaneous avoidance of competitors and, in many places, humans. In areas of high natural food availability, black bear tend to avoid humans and human-altered landscapes (Beckmann & Berger, 2003). In areas of range overlap with competing, sympatric grizzly bear, black bear's avoidance of grizzlies has been documented to result in increased temporal and spatial overlap with human activity (Apps et al., 2006;Belant et al., 2010;Ladle et al., 2018). ...
Article
Full-text available
Aim Decades of research on species distributions has revealed geographic variation in species‐environment relationships for a given species. That is, the way a species uses the local environment varies across geographic space. However, the drivers underlying this variation are contested and still largely unexplored. Niche traits that are conserved should reflect the evolutionary history of a species whereas more flexible ecological traits could vary at finer scales, reflecting local adaptation. Location North America. Methods We used mammal observations during a 5‐year period from the iNaturalist biodiversity database and a local ensemble modelling approach to explore spatial variation in American black bear (Ursus americanus) relationships with eight ecological correlates. We tested four biologically driven hypotheses to explain the patterns of local adaptation. We evaluated non‐stationarity in ecological relationships using a Stationarity Index and tested predictive performance using an independent, national‐level animal occurrence data set. Results We documented considerable spatial non‐stationarity in all eight environmental relationships, with the greatest spatial variation occurring in bear's relationship to climatic factors. Notably, the greatest variation in environmental relationships tended to occur along the current boundaries of the species' range, potentially representing the ecological limits to the species geographic range. We additionally documented that spatial variation in relationships with land cover and anthropogenic factors were best explained by niche conservatism at the subspecies level, whereas climatic relationships were better explained by local adaptation. Main Conclusions Based on these results, we propose that the current distribution of American black bear is determined by an evolutionary legacy of habitat relationships unique to each subspecies combined with more fine‐scale local adaptation to climatic conditions. This result suggests that black bears should be adaptable to climatic changes over the 21st century and that management of habitat and human‐bear relationships could be considered at the subspecies level.
... Human-altered energetic environments (additional food or heated areas in winter) have contributed to reductions in migration (e.g. [52,53]) and torpor [54]. ...
Article
Full-text available
Freezing temperatures are inherently challenging for life, which is water based. How species cope with these conditions fundamentally shapes ecological and evolutionary processes. Despite this, there is no comprehensive conceptual framework for cold-survival strategies—seasonal migration, cold resistance and torpor. Here, I propose a framework with four components for conceptualizing and quantifying cold-survival strategies. Cold-survival strategies are (i) collectively encompassed by the proposed framework, and that this full breadth of strategies should be considered in focal species or systems ( comprehensive consideration ). These strategies also (ii) exist on a spectrum, such that species can exhibit partial use of strategies, (iii) are non-exclusive, such that some species use multiple strategies concurrently ( combined use ) and (iv) should collectively vary inversely and proportionally with one another when controlling for the external environment (e.g. when considering species that occur in sympatry in their summer range), such that use of one strategy reduces, collectively, the use of others ( proportional use ). This framework is relevant to understanding fundamental patterns and processes in evolution, ecology, physiology and conservation biology.
... In red foxes in Saudi Arabia territoriality became absent as they concentrated their activities around ephemeral but rich anthropogenic food sources (Macdonald et al., 1999). Greater resource availability led to shorter hibernation times in North American black bears (Beckmann and Berger, 2003). ...
Article
Full-text available
Urban spotted hyenas (Crocuta crocuta) in Ethiopia are a prime example of large carnivores coexisting with little to no conflict with people in a human-dominated landscape, providing a valuable waste-removal service. To gain insight in how this urban lifestyle persists across generations, we studied hyena group composition at the city waste dump of Mekelle, a regional capital in northern Ethiopia. We found that hyena cubs and sub-adults foraged with adults in groups of highly variable composition. Young urban hyenas already take part in a fission-fusion dynamic that is also characteristic of hyenas in non-urban environments. They do not seem to learn from only one or few close reference adults. Social network analysis revealed no clusters among these dump-visiting hyenas. The number of counted hyenas is furthermore larger than any hyena clan in non-urban areas. All individuals were more or less equally connected to each other, and each hyena had a few connections, but to different individuals. All cubs and sub-adults were connected to each other, over a maximum of four links. Hyenas shared the abundance of food at the waste dump without overt aggression. A much larger number of urban hyenas shares this waste dump at night than would fit into a single forest fragment, such as those associated with orthodox churches where small groups of hyenas have often been observed to rest at daytime. Hyenas appear to commute from different dens and resting sites located around the city, but we have no information on their behavior and group composition away from the dump. We observed no defense of any part of the dump area by any of the foraging groups. In absence of territorial behavior at this city site, the clan concept does not seem to apply to these urban hyenas. Similar to what has been observed in other urban carnivores, individuals at the waste dump behaved as members of conflict-free foraging groups ostensibly sharing food without aggression. Perhaps this is what most strikingly defines their urbanity.
... Alt et al. (1980) and others found that among wild bears, males maintain home ranges about 4 times larger than females. Beckmann and Berger (2003) showed that urban black bears had significantly smaller home ranges in comparison to non-urban individuals. Pop et al. (2012) suggested that home range sizes were strongly affected by the previous experience of the individual bear with humans, and found that habituated bears that are relocated will first explore the unknown release site prior to dispersing to their former home range. ...
Article
Black bear (Ursus americanus) populations in California have increased in abundance and distribution despite rising trends in the urban encroachment of wildlands. As human-black bear conflicts increase, opportunities to study the relocation of black bears in an adaptive management setting are important for improving the management of this highprofile species. Habituated black bears, some tamed and made tractable through human-controlled food conditioning, were relocated to a remote region of the Klamath Mountains to analyze home range use, survival, return rates, and mortality. Relocated black bears with known outcomes demonstrated an 80% return rate, with 55% not surviving beyond five months. Female bears established home ranges significantly larger than males, and may suggest an enhanced maternal instinct in search of similar nutritional conditions prior to relocation. This study showed that the relocation of food-conditioned black bears resulted in high return rates, poor survival, and risk to public safety.
... Continual conflicts between humans and bears have become a serious problem in North America, Europe, and Asia (Beckmann and Berger 2003, Perveen and Abid 2013, Elfström et al. 2014. In Japan, Asiatic black bears (Ursus thibetanus) occupying areas in and around human settlements can damage property and threaten human safety (Yokoyama 2011). ...
Article
Increased occurrences of bears in human settlements in search of food have led to a high incidence of human–bear interactions in Japan; therefore, a better understanding of bear occurrence in relation to bears' diet is required to establish effective management practices. In this study, we investigated the composition of the diet of Asiatic black bears (Ursus thibetanus) and the number of bear sightings in Shirakawa Village, Gifu Prefecture, Japan, during pre- and hyperphagic periods (Aug–Dec) from 2008 to 2016. In years with low numbers of sightings, bears consumed natural foods in natural areas, such as fruits of Japanese bird cherry (Prunus grayana), dogwood (Swida controversa), oak (Quercus spp.), and beech (Fagus crenata), which constituted the main part of the bears' diet in our study area. In years with a medium number of sightings, bears consumed both natural and anthropogenic foods in or near human habitations, such as Japanese chestnut (Castanea crenata) and kaki (Diospyros kaki). In the high-sighting year of 2014, bears exhibited a particularly strong preference for Japanese walnut (Juglans mandshurica) and kaki. The number of bear sightings was negatively related to the consumption rates of Japanese bird cherry, dogwood, oak, and beech, and positively related to the consumption rates of Japanese walnut, Japanese chestnut, and kaki. These findings suggest that consumption of fleshy fruits in late summer or hard mast in autumn in or near human settlements has a large effect on the risk of bear–human interactions.
... Some studies support this idea. Access to human food waste in urban areas has been linked to reduced home ranges in raccoons (Bozek, Prange, and Gehrt 2007), increased population densities in coyotes (Fedriani, Fuller, and Sauvajot 2001) and reduction in time spent foraging in black bears (Beckmann and Berger 2003). These benefits, however, are the result of the additional calories present in the food waste. ...
Article
Full-text available
Urban areas provide animals with both a unique set of challenges and resources. One of the novel resources available in urban areas is an abundance of human food waste. Although it is known that many urban-dwelling animals are consuming human food waste at some level, there is not a good understanding of the nutrients provided by this novel resource. Given that human food waste is unlikely to resemble an animal’s natural diet, there could be health consequences for an animal consuming human food waste. In some animals, nutritional imbalances can also lead to behavioral changes, making it important to understand more precisely what they are eating. To answer the question of what nutrients were available in urban food waste, we surveyed food waste in the Philadelphia–Camden urban matrix. We found that human food waste contained ∼1000% more carbohydrates than other nutrient types. Given the impact that carbohydrate-rich diets can have on human health, there may be important consequences for the animals in urban environments that consume this food waste. Therefore, it is possible that human food subsidies have cascading consequences for entire communities and their ecosystem services in cities.
... We focused our field data collection on cougar predation behavior at times when cougars most frequently encounter black bears (i.e., bear active season). Thus, we only used kill-site investigation data for cougar kills made between 1 March and 31 October of each year for these analyses (Beckmann & Berger, 2003a, 2003b. The use of seasonal data differs from another study of cougars in the area with foraging behavior from year-long data (Andreasen et al., 2021). ...
Article
Full-text available
Apex predators can shape communities via cascading top–down effects, but the degree to which such effects depend on predator life history traits is largely unknown. Within carnivore guilds, complex hierarchies of dominance facilitate coexistence, whereby subordinate species avoid dominant counterparts by partitioning space, time, or both. We investigated whether a major life history trait (hibernation) in an apex carnivore (black bears Ursus americanus) mediated its top–down effects on the spatio-temporal dynamics of three sympatric mesocarnivore species (coyotes Canis latrans, bobcats Lynx rufus, and gray foxes Urocyon cinereoargenteus) across a 15,000 km² landscape in the western USA. We compared top–down, bottom–up, and environmental effects on these mesocarnivores using an integrated modeling approach. Black bears exerted top–down effects that varied as a function of hibernation and were stronger than bottom–up or environmental impacts. High black bear activity in summer and fall appeared to buffer the most subordinate mesocarnivore (gray foxes) from competition with dominant mesocarnivores (coyotes and bobcats), which were in turn released by black bear hibernation in winter and early spring. The mesocarnivore responses occurred in space (i.e., altered occupancy and site visitation intensity) rather than time (i.e., diel activity patterns unaffected). These results suggest that the spatio-temporal dynamics of mesocarnivores in this system were principally shaped by a spatial predator cascade of interference competition mediated by black bear hibernation. Thus, certain life history traits of apex predators might facilitate coexistence among competing species over broad time scales, with complex implications for lower trophic levels.
Article
American black bear ( Ursus americanus ) populations are increasing throughout much of North America. Use of multiple harvest methods, including hunting over bait, is intended to increase harvest success rates to meet harvest and population management objectives. However, black bear population growth can be influenced by food availability, and some speculate the use of bait may inadvertently increase bear abundance through food resource supplementation. We collected hair from black bears captured from 2005–2019 and a selection of potential food items, including those used as bait from 3 study areas in Maine, USA, with different levels of human influence. We used stable isotope analysis of the black bear hair and food item samples to evaluate the contribution of different identified food groups to the diet of individual bears. We found no evidence that greater contribution of human food resources, including bait, increased the number of cubs per litter for reproductive females or that human foods comprised a greater part of the diet in years when natural food resources were less abundant. Approximately 69% of black bear harvest occurred over bait. We found the probability of reproductive‐age females to be harvested increased with average representation of human foods with high carbon enrichment (including bait) in their diet, but the relationship was weak, likely because of sampling constraints. Additionally, the probability of being harvested was greater in years when natural food resources were scarce. We conclude that bait is not available on the landscape in large enough amounts or for a sufficient amount of time in Maine to substantially influence female reproduction. Our results indicate hunting over bait is an effective tool in a state that is attempting to maintain a stable bear population via harvest, and dispels conjecture that hunting over bait may increase cub production and offset the intention of harvest.
Article
Full-text available
Garbage may cause substantial environmental perturbations, in part because of its consumption by wildlife. Such consumption may have direct health implications for animals and may also influence trophic relationships. Even in pristine Arctic ecosystems, wildlife feeding in marine environments consume garbage in the form of plastic debris transported by ocean currents. We show that Arctic wildlife in pristine terrestrial environments may also ingest garbage or food items derived from abandoned camp sites. We found the remains of a chocolate wrapper and a milk powder bag in two Arctic fox (Vulpes lagopus) scats and a piece of cloth in an Arctic wolf (Canis lupus arctos) scat collected near Nares Strait, northern Greenland, one of the most pristine terrestrial wilderness regions on Earth. Found on Washington Land and associated with long-abandoned camp sites, these three scats were among 657 Arctic fox scats and 92 wolf scats collected as part of a larger study. Our study demonstrates that these two highly opportunistic predators managed to consume garbage despite the almost complete lack of human activity in this High-Arctic region. Our results highlight that abandoned anthropogenic material in the High Arctic may function as a source of garbage for local terrestrial wildlife over extended time periods, and that garbage consumption may become a potential issue if human activity in remote Arctic regions increases.
Article
Full-text available
Over the last hundred years, many large carnivore species have suffered range contractions, population losses, and habitat alterations that may be influencing their dietary preferences. To identify shifting isotopic niches and reconstruct past and present diets from species of high conservation concern, stable isotope analysis (SIA) of δ¹³C and δ¹⁵N values of tissue from museum collections and ongoing non-invasive monitoring programs offers an effective approach. Here, we assessed the long-term alterations in the trophic structure of a generalist large carnivore over a time of population loss and recovery. Wolverine stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes were measured in hair samples collected from 44 individuals in Finland for the period 1905–2020, and potential dietary were quantified using isotopic niche metrics shifts in two study areas. We provide evidence of a long-term diet shift in Finnish wolverines, with a temporal depletion of hair’s δ¹³C (β = −0.016‰, R² = 0.46, p < 0.001). Correspondingly, there was a shift in the isotopic niches of the Historical population (before the year 2000) and Recent population (after 2000), with the niche overlap between the Historical and Recent periods being only 33% throughout Finland, and even lower in the two study areas (22% to 24%). The breadth of the isotopic niche, however, did not significantly differ between the two periods, suggesting that despite a change in diet composition, wolverines did not specialize more. The trophic level of wolverines in Finland was stable throughout the study period, with no significant change in δ¹⁵N with time (β = 0.0055‰, R² = 0.043, p = 0.17). In summary: A) the strong trophic resilience of this top predator was shown by the stability of its niche breadth and trophic level feeding regime during periods of population decline and recovery as well as during a period of major anthropogenic alterations in their environment; B) the use of SIA methods on historical and recent hairs provided a unique tool to unravel long-term changes in wolverine feeding strategies.
Article
Full-text available
In the Southern Appalachian region of the United States, harvest data has indicated the occurrence of low deer densities while exposing a trend of declining white-tailed deer (Odocoileus virginianus) populations over the past several decades in northern Georgia. A triumvirate of increasing fawn predator populations reside in the Southern Appalachian Mountains including coyotes (Canis latrans), black bears (Ursus americanus) and bobcats (Lynx rufus). This region is also characterized by a homogenous landscape composed of mature forests and sparse understory vegetation, likely lacking adequate cover to offer fawns refugia from predators. Our objectives were to estimate survival and cause-specific mortality rates of fawns while assessing a possible link between mortality risk, intrinsic fawn characteristics (i.e., birth mass, Julian birth date, sibling status), and landscape features within fawn usage areas. During 2018–2020, we radio-collared 71 fawns within the Chattahoochee National Forest of northern Georgia, USA and monitored survival to 12 weeks of age. We observed low fawn survival (cumulative = 0.157, 95% CI = 0.091–0.273; vaginal implant transmitter = 0.196, 95% CI = 0.096–0.403) with predation as the leading cause of all known mortalities (45 of 55 mortalities; 82%) due primarily to coyotes (n = 22), black bears (n = 12), and bobcats (n = 7). Relationships between landscape features and fawn predation risk were minimal with only one informative covariate. Increasing amounts of early successional land cover within fawn usage areas decreased fawn mortality risk within the first 20 days of life, but elevated mortality risk thereafter. All fawns with any amount of early successional land cover in their usage areas died of predation (n = 13) at various time intervals, suggesting limited areas of potential fawning cover may be targeted by predators. However, fawn predation risk seemed to be high regardless of landscape covariates due to the limited number of surviving fawns. Coyote-caused mortality occurred over a longer period at a consistently higher magnitude than all other forms of mortality, indicating possible delayed prey-switching behavior and coyote predation as an important factor of fawn survival. The low recruitment of fawns influenced by high predation rates and homogenous habitat conditions is likely the cause of deer population declines in the region.
Article
Full-text available
Climate change and urbanisation are among the most pervasive and rapidly growing threats to biodiversity worldwide. However, their impacts are usually considered in isolation, and interactions are rarely examined. Predicting species' responses to the combined effects of climate change and urbanisation, therefore, represents a pressing challenge in global change biology. Birds are important model taxa for exploring the impacts of both climate change and urbanisation, and their behaviour and physiology have been well studied in urban and non-urban systems. This understanding should allow interactive effects of rising temperatures and urbanisation to be inferred, yet considerations of these interactions are almost entirely lacking from empirical research. Here, we synthesise our current understanding of the potential mechanisms that could affect how species respond to the combined effects of rising temperatures and urbanisation, with a focus on avian taxa. We discuss potential interactive effects to motivate future in-depth research on this critically important, yet overlooked, aspect of global change biology. Increased temperatures are a pronounced consequence of both urbanisation (through the urban heat island effect) and climate change. The biological impact of this warming in urban and non-urban systems will likely differ in magnitude and direction when interacting with other factors that typically vary between these habitats, such as resource availability (e.g. water, food and microsites) and pollution levels. Furthermore, the nature of such interactions may differ for cities situated in different climate types, for example, tropical, arid, temperate, continental and polar. Within this article, we highlight the potential for interactive effects of climate and urban drivers on the mechanistic responses of birds, identify knowledge gaps and propose promising future research avenues. A deeper understanding of the behavioural and physiological mechanisms mediating species' responses to urbanisation and rising temperatures will provide novel insights into ecology and evolution under global change and may help better predict future population responses.
Article
Full-text available
Introduction To sustain black bear (Ursus americanus) populations, wildlife managers should understand the coupled socio-ecological systems that influence acceptance capacity for bears. Method In a study area encompassing a portion of New York State, we spatially matched datasets from three sources: human-bear conflict reports between 2006 and 2018, estimates of local bear density in 2017–2018, and responses to a 2018 property owner survey (n=1,772). We used structural equation modeling to test hypothesized relationships between local human-bear conflict, local bear density, and psychological variables. Results The final model explained 57% of the variance in acceptance. The effect of bear population density on acceptance capacity for bears was relatively small and was mediated by a third variable: perception of proximity to the effects of human-bear interactions. The variables that exerted a direct effect on acceptance were perception of bear-related benefits, perception of bear-related risks, perceived proximity to effects of human-bear interactions, and being a hunter. Perception of bear-related benefits had a greater effect on acceptance than perception of bear-related risks. Perceived proximity to effects of human-bear interactions was affected by local bear density, but also was affected by social trust. Increased social trust had nearly the same effect on perceived proximity as decreased bear density. Social trust had the greatest indirect effect on acceptance of any variable in the model. Discussion Findings suggest wildlife agencies could maintain public acceptance for bears through an integrated approach that combines actions to address bear-related perceptions and social trust along with active management of bear populations.
Article
Full-text available
Background Human-induced changes to ecosystems transform the availability of resources to predators, including altering prey populations and increasing access to anthropogenic foods. Opportunistic predators are likely to respond to altered food resources by changing the proportion of food they hunt versus scavenge. These shifts in foraging behavior will affect species interactions through multiple pathways, including by changing other aspects of predator behavior such as boldness, innovation, and social structure. Methods To understand how foraging behavior impacts predator behavior, we conducted a controlled experiment to simulate hunting by introducing a prey model to captive coyotes ( Canis latrans ) and compared their behavior to coyotes that continued to scavenge over one year. We used focal observations to construct behavioral budgets, and conducted novel object, puzzle box, and conspecific tests to evaluate boldness, innovation, and response to conspecifics. Results We documented increased time spent resting by hunting coyotes paired with decreased time spent active. Hunting coyotes increased boldness and persistence but there were no changes in innovation. Our results illustrate how foraging behavior can impact other aspects of behavior, with potential ecological consequences to predator ecology, predator-prey dynamics, and human-wildlife conflict; however, the captive nature of our study limits specific conclusions related to wild predators. We conclude that human-induced behavioral changes could have cascading ecological implications that are not fully understood.
Article
Full-text available
Foraging by wildlife on anthropogenic foods can have negative impacts on both humans and wildlife. Addressing this issue requires reliable data on the patterns of anthropogenic foraging by wild animals, but while direct observation by researchers can be highly accurate, this method is also costly and labor‐intensive, making it impractical in the long‐term or over large spatial areas. Camera traps and observations by guards employed to deter animals from fields could be efficient alternative methods of data collection for understanding patterns of foraging by wildlife in crop fields. Here, we investigated how data on crop‐foraging by chacma baboons and vervet monkeys collected by camera traps and crop guards predicted data collected by researchers, on a commercial farm in South Africa. We found that data from camera traps and field guard observations predicted crop loss and the frequency of crop‐foraging events from researcher observations for crop‐foraging by baboons and to a lesser extent for vervets. The effectiveness of cameras at capturing crop‐foraging events was dependent on their position on the field edge. We believe that these alternatives to direct observation by researchers represent an efficient and low‐cost method for long‐term and large‐scale monitoring of foraging by wildlife on crops. Understanding anthropogenic foraging by researcher observation is costly and labor‐intensive. We investigated whether camera traps and crop guard records could give the same insights as researcher observation into patterns of crop‐foraging by baboons and vervet monkeys. Camera and guard data predicted data from researchers for baboons, and to an extent, vervets, and therefore present a viable alternative to researcher observation allowing for large‐scale and long‐term monitoring of crop‐foraging.
Article
Management of free-ranging wildlife may include the capture of animals, with the implication that the capture process is optimized, both logistically and economically and in a way that avoids animal suffering, injury or accidental mortality. Studies targeting the optimization of trapping techniques are scarce, especially when focusing on large European mammals. Therefore, to fill this knowledge gap, we aimed to evaluate key factors that help determine brown bear capture success. This was done by analysing a complete data set from 23 years of capturing free-living Eurasian brown bears in Croatia by using Aldrich-type foot snares. Results showed significantly higher capture efficiency when traps were located at permanent feeding sites when compared to temporary feeding sites. Also, the use of a trail trap design was significantly more efficient in capturing bears than using a cubby set. Finally, results showed that trapping was more efficient when we bait the traps more frequently and when we implemented longer trap-sessions, with at least 14 days.
Article
Full-text available
In temperate regions of the world, food resources are seasonally limited, which causes some wildlife species to seek out nutrient‐rich resources to better meet their caloric needs. Animals that utilize high‐quality resources may reap fitness benefits as they prepare for mating, migration, or hibernation. American black bears (Ursus americanus) are omnivores that consume both plant and animal food resources to meet macronutrient needs. Black bears capitalize on high‐quality food resources, such as soft mast in summer and hard mast during autumn, but we know less about the importance of resource quality during spring. Therefore, we sought to understand the relationship between the spatiotemporal variation in the availability of food and resource selection of black bears during spring. We also aimed to infer potential changes in foraging tactics, from opportunistic foraging to more active selection. Although black bears are described as opportunistic omnivores, we hypothesized they select areas with high‐quality forage when available. We instrumented 7 black bears with GPS collars in 2017 and 2018 and estimated fine‐scale resource selection with integrated step‐selection functions. We found evidence that black bear movements were influenced by forage quality of vegetative food resources. However, we failed to find evidence that black bears actively alter their movements to take advantage of seasonal neonate elk. Although black bears represent a substantial cause of mortality for neonate elk, we found that black bears likely feed on neonates encountered opportunistically while traveling between patches of high‐quality forage. Few studies have shown evidence of an omnivorous species capitalizing on spatiotemporal variation in forage quality, yet our data suggest this may be an important strategy for species with diverse diets, particularly where resources are seasonally limited.
Article
Urbanization creates novel ecological spaces where some species thrive. Geographical urbanization promotes human–wildlife conflict; however, we know relatively little about the drivers of biological urbanization, which poses impediments for sound wildlife management and conservation action. Flying-foxes are extremely mobile and move nomadically in response to flowering resources, but are now increasingly found in urban areas, for reasons that are poorly understood. To investigate the mechanisms behind flying-fox urbanization, we examined the movement of 99 satellite tracked grey-headed flying-foxes (Pteropus poliocephalus) over 1 year in urban versus non-urban environments. We found that tracked individuals preferentially visited major-urban roosts, exhibited higher fidelity to major-urban roosts, and foraged over shorter distances when roosting in major-urban areas. In contrast to other colonial species, there were no density-dependent effects of colony size on foraging distance, suggesting that at a landscape scale, flying-foxes distribute themselves across roosts in an ideal-free manner, minimizing competition over urban and non-urban foraging resources. Yet, males consistently foraged over shorter distances than females, suggesting that at a local scale foraging distances reflect competitive inequalities between individuals. Overall, our study supports the hypothesis that flying-fox urbanization is driven by increased spatiotemporal availability of food resources in urban areas; however, unlike in other species, it is likely a consequence of increased urban visitation by nomadic individuals rather than a subset of the population becoming “urban residents” per se. We discuss the implications of the movement behavior we report for the conservation and management of highly mobile species.
Chapter
Full-text available
This chapter explores three aspects of conflictive brown bear behaviour in the Cantabrian Mountains. Firstly, we argue the reasons of why bears approach humanised areas, what constitutes habituation and what their causes and consequences are. Secondly, we present the problem of bears and human garbage. We revise the worldwide literature of the effect of garbage on bears and present the results of a field study undertaken in 2019 in the municipalities of Somiedo (Asturias) and Villablino (León). These show that bears have easy access to garbage containers, many of which are very close to wild habitat in areas of very low night-time illumination. However, until 2019, we knew of almost no cases of bears coming to visit containers frequently, but over the past two years a few bears with this habit have appeared, reminding us that this is a significant problem affecting the majority of bear populations. We make a few suggestions of how to reduce the presence of bears in towns and villages and go over the importance of the prevention and aversive conditioning in order to dissuade bears conditioned to garbage. Finally, we summarise the characteristics of the brown bear attacks on humans in Spain which have occurred since 1989. A total of seven attacks have occurred (aggressive encounters with physical contact) in the Cantabrian Mountains and one in the Pyrenees, all of which were caused by sudden encounters, produced light to moderate injuries and lasted just a few seconds until the bear fled. All of these attacks in the Cantabrian Mountains have occurred in the eastern subpopulation, which may derive from genetic differences affecting bear behaviour between the two Cantabrian nuclei.
Article
Archived serum samples taken between 1997 and 2017 from 170 American black bears (Ursus americanus) in the Lake Tahoe area between California and Nevada, US, were tested for Toxoplasma antibodies to assess the seroprevalence of this agent. Samples were screened using a commercial porcine Toxoplasma (enzyme-linked immunosorbent assay [ELISA]) modified with Protein A/G peroxidase and compared to a traditional fluorescent antibody test. Results were analyzed to determine if there were differences in seroprevalence based on the test used, sex of bears, or habitat usage (urban-suburban vs. wildland). No significant differences in seroprevalence were attributable to any of these parameters. The overall seropositivity for bears was 36% (62/170), with urban-suburban bears scoring lower (31%; 37/119) than rural-wildland bears (40%; 18/45). Our results strongly support the use of a Protein A/G-modified ELISA for determining Toxoplasma exposure in black bears. We found somewhat lower levels of Toxoplasma antibodies in black bears from this region than in several reports from populations in the eastern US.
Article
Full-text available
We compiled and analyzed 24 years (1972-1995) of verified incidents of mountain lions killing domestic animals (n = 2,663) to examine trend, distribution, and types of conflicts in California. To model the relationships between mountain lion depredation and various human activity and habitat factors, we tested 2 predictive models. Domestic sheep depredation in counties was significantly (P < 0.05) related to amount of suitable mountain lion habitat. We hypothesize that increasing domestic sheep depredation may reflect regional increases in the distribution and abundance of mountain lions. A regression model of percent pet depredation indicated a significant (P < 0.05) association with average annual new house development (1979-1993). Counties with significant pet depredation are in the same regions where public safety problems have occurred and reflect a radiation of human activity into mountain lion habitat. Mountain lion depredation data may be a useful index of regional mountain lion activity. Livestock and pet depredation problems are increasing in different regions of the state for different reasons; pet depredations are increasing the most rapidly. Pet depredation may be a useful indicator of mountain lion proximity to humans.
Chapter
Full-text available
Article
Full-text available
Aerial locations of radio-instrumented grizzly bears (Ursus arctos) were used to analyze effects of human activity associated with developments and primary roads on grizzly bear habitat use in Yellowstone National Park. Grizzly bear occupancy of habitat near human facilities was reduced, efficient foraging strategies were disrupted, and cohorts tending to be subordinate or security-conscious were displaced into habitat nearer developments by more dominant cohorts, particularly during summer and fall. Adult females and subadult males residing closer to developments were management-trapped at a higher rate than animals of the same class residing farther away. Adult females and subadults bore a disproportionate part of costs associated with avoiding roads and developments. For this reason and because adult females are generally thought to operate under considerable energetic duress in the Yellowstone area, avoidance of developments and roads may have resulted in higher mortality and lower productivity among the adult female cohort.
Article
Full-text available
Data on home range, activity and behavior of a single coyote (Canis latrans) in Lincoln, Nebraska, were obtained by radiotelemetry and direct observations during spring and summer 1976. Its home range was 7.4 km2. Seventy percent of the coyote's locations were in a well-developed, 14-ha residential area where he had abundant food, protective cover, little harassment by humans and interactions with at least 12 dogs. The coyote was most active from 0030 to 0600 hr and 1730 to 2130 hr.
Article
Full-text available
Managers trying to preserve populations of endangered carnivores are often forced to choose between restoring habitat to allow larger breeding populations or reduce risks of mortality to increase survival rates. We modelled the viability of a metapopulation of the Iberian lynx (Lynx pardinus) under several scenarios (habitat restoration, anti-poaching, reduction in road kills) in a real landscape to evaluate their relative effects. Increasing carrying capacity was highly effective when performed on the local populations that acted as sources but had no effect when carried out in the sinks. Realistic scenarios consisting of partial removal of the human-related mortality (assuming additive effects of causes) predicted high risk of extinction. When combined, the effects of both management options are highly dependent on where they are carried out. If the sinks are the only targets of carrying capacity enlargement, a complete removal of human-caused mortality is required, whereas increases in the carrying capacity of sources are always effective. The metapopulation risk of extinction decreases dramatically (from 45.5% to 2.1% in 100) if connectivity among source populations can be improved. According to our work, only a detailed knowledge of the spatial and demographic structure of the populations, combined with simulations of realistic situations, can help managers to select the a priori optimal strategy, which probably combines different management options.
Article
Full-text available
Models on the distribution of animals are invaluable in understanding how individuals and, ultimately, populations respond to ecological processes. Rarely, have they been applied to conservation issues at a landscape level. We capitalized on the distribution of a previously unavailable novel food resource, found at the juxtaposition of urban and wildland areas, to test the generality of ideal-free distribution (IFD) models using a mammalian carnivore, the black bear (Ursus americanus). The primary question we addressed was whether an increase in the prevalence of individuals in a geographical region reflects a population increase or a landscape level redistribution. Combining spatial and temporal data sets with empirically obtained information spanning 12–15 years, we contrasted demographic, life-history, and reproductive parameters between individuals at urban–wildland interface (ex-perimental) and wildland (control) areas at the interface of the Sierra Nevada Range and Great Basin Desert in western North America. Bears were expected to respond to natural versus artificially clumped resources according to an IFD model. Evidence only partially supported this idea because individuals in urban areas had densities 3 times the historical values from the same area, sex ratios were 4.25 times more skewed toward males, bears had 30% larger body mass, home ranges were reduced by 90% for males and 70% for females, and bears entered dens significantly later than wildland conspecifics. However, females in urban-interface areas gave birth to 3 times the number of cubs, although only half as many dispersed successfully relative to wildland females. Further, urban-interface females had a higher proportion (0.57) of potential reproductive years, in which they had young, compared with wildland females (0.29). We present evidence suggesting that bears in Nevada and in the Lake Tahoe basin conform primarily to an ideal-despotic distribution model. Our findings on population reallocation, rather than demographic increase, reem-phasize how knowledge about correlates of individual performance and distribution over time helps to understand the extent to which humans change ecosystems, whether their actions are intentional or not.
Article
Full-text available
Few studies have reported the effects of multiple human activities on grizzly bears, Ursus arctos. We document the degree of grizzly bear response to various human developments as a function of multiple interacting variables based on observed median distances to roads, trails and development features in a landscape where human presence is widespread. Female grizzly bears remained further than males from paved roads regardless of habitat quality or time of day. Males were found closer to paved roads when within or adjacent to high quality habitat and during the period of least human activity. The combination of traffic volume and highway configuration, however, overrides a bear’s attraction to high quality habitats for high-speed, high-volume, highways. Avoidance of busy transportation corridors was strongest in the adult segment of the population. Bears were found closer to trails during the human inactive period when within high quality habitat and further from trails when distant to high quality habitat. Our data indicated an inverse relationship between the sexes in response to vehicles and traffic noise compared to the response to human settlement and encountering people. Female bears were found further away than males in relation to vehicles and traffic noise, yet found closer than males to human settlement and places where people may be encountered. Those males that were more willing to exploit high quality habitat near roads, did so at night and where hiding cover was present. Adult females were the most risk-averse cohort, choosing to avoid humans instead of seeking out high quality habitats. Adult female grizzly bears were influenced most by human activities and development. Management agencies must maintain access to high quality habitat, especially for adult females, and create new opportunities to support the reproductive potential of the population.
Article
Full-text available
Rabies was confirmed as the cause of death of one African wild dog (Lycaon pictus) in the Serengeti region, Tanzania. One adult African wild dog in the same pack showed central nervous signs consistent with rabies infection. Inactivated rabies vaccine was administered intramuscularly to African wild dogs in two packs, by dart or by hand following anesthesia. These individuals comprised all known adults in the Serengeti National Park. In a limited study of seroprevalence of rabies antibody carried out at the time of vaccination, 3 of 12 African wild dogs sampled in the Serengeti had rabies serum neutralizing antibody titers before vaccination. Paired serum samples from two individuals sampled after vaccination showed increased antibody titers.
Article
Full-text available
Canine distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti-Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.
Article
Black Bears (Ursus americanus) are usually active during daylight but are known to shift to crepuscular and nocturnal activity when daylight activities are disrupted. The principle factors currently thought to promote this shift are the presence of Brown Bears (U. arctos) and humans. I examined the extent of diurnal, crepuscular and nocturnal activity of Black Bears in an estuary and stream during salmon spawning migration at Bag Harbour, Haida Gwaii, off coastal British Columbia. A predominance of daylight activity was predicted as there are no Brown Bears on Haida Gwaii and only minimal human disturbance in the remote area. Results show that during daylight, there was low but consistent foraging activity in the stream but no daylight foraging on the estuary even when salmon were abundant. Bears were intolerant of each other during daylight and would rarely forage within visual range of each other. Use of night-viewing goggles show that most foraging on the stream and all foraging on the estuary occurred during darkness with peak activity four to six hours after sunset. Up to six bears foraged simultaneously in the shallows in close proximity to each other with few agonistic interactions. High foraging success during darkness occurred because salmon showed reduced evasive responses to shoreline disturbance compared with daylight. These observations suggest that occasional nocturnal activity by Black Bears on the mainland of western North America might be the result of preferred foraging periods rather than disturbance with diurnally active competitors.
Article
Coyotes (Canis latrans) are common residents of many urban areas in North America, but little is known about how they have adapted to urbanization. With increasing urban sprawl, it is important to understand how and why animals are using urban landscapes. We studied radiocollared coyotes in Tucson, Arizona, USA, from October 1996 to December 1998 to determine home range size, habitat use, and nocturnal movement patterns in 7 habitat patch types: natural, commercial, parks, vacant, residential, washes, and roads. Home ranges of resident coyotes averaged 12.6 km2 (range = 1.7 to 59.7 km2). Home ranges encompassed a smaller portion of natural patches and a larger proportion of park and residential areas than were available in the study area. Coyotes used habitat patch types within the home ranges in proportion to their availability, except during the dispersal season, when coyotes selected natural areas and washes and avoided park and residential areas. We used radiolocation data from 120 nighttime observation sessions of 11 animals to determine nocturnal movement patterns. Rates of movement peaked at 2300 and 0500 hr. Rates of movement did not differ among habitat patch types. Individuals moved minimum distances of 1.3 to 6.2 km during the night. Coyotes were most active at night from 2200 to 2400 hr. Disturbances associated with urbanization are multi-scaled and widespread; therefore, wildlife biologists and managers should study habitat use by urban wildlife at multiple scales.
Article
We studied factors affecting the chronology of denning by 104 female black bears (Ursus americanus) from three areas in Maine from 1982 to 1988. At two areas in northern Maine, entry into dens followed an alternate-year pattern with most bears denning in mid to late October when beechnuts (Fagus grandifolia) were scarce, and in mid to late November the next year when nuts were abundant. This pattern may have occurred for greater-than-or-equal-to 11 years and has not been reported previously for a black bear population. From 1986 to 1988, patterns of habitat use reflected another behavioral response to beechnut crops; bears used hardwood forests more during autumns when nuts were abundant. Annual variation in den entry was not strongly associated with weather patterns during autumn. Where beech trees were less common in central Maine, den entry and habitat use varied less among years. Pregnant females tended to den earlier than other females. Den emergence was similar among reproductive classes, generally occurring during April within 7 days of the final snow melt. Denning periods for individuals ranged from 134 to 197 days. We concluded that black bears generally remain active in autumn until a negative energy balance occurs, but we hypothesized that pregnant females may den after they store adequate fat reserves for reproduction.
Article
Four parameters out of the five investigated were found useful for studying white-tailed deer (Odocoileus virginianus) movements by triangulation with an automatic radio-tracking system. These were total area, greatest linear dimension, mean activity radius and distribution of activity radii, and appearance of the map. Random plots, which simulated deer movements, were used to determine the effects of varying the location of the animal's range in relation to the triangulation stations. Results show an increase in size of range and a loss in accuracy of location as the plots were moved out. An "hour-glass-shaped" area of about 3,300 acres is considered to be within acceptable accuracy with a 0.5-mile base line and a ±0.5° resolution. Point locations were obtained at 1-min intervals for selected time periods for three deer. These data were then sampled at intervals of 2, 3, 4, 5, 6, 10, 15, 30, and 60 min. Values for total area and greatest dimension decreased and the mean activity radius increased as the sampling interval became longer. A sufficient number of point locations can be maintained by using a short sampling interval or long observation period. Comparisons of home range size were made among individual deer and between a winter and an early spring period using the above four parameters. Spring ranges were significantly larger than winter ranges and movements in spring were longer with less concentration of activity. The differences between winter and spring behavior are probably related to higher spring temperatures and the disappearance of snow.
Article
The Yellowstone grizzly bear (Ursus arctos horribilis) population may be extirpated during the next 100-200 years unless mortality rates stabilize and remain at acceptable low levels. Consequently, we analyzed relationships between Yellowstone grizzly bear mortality and frequency of human habituation among bears and size of the whitebark pine (Pinus albicaulis) seed crop. During years of large seed crops, bears used areas within 5 km of roads and 8 km of developments half as intensively as during years of small seed crops because whitebark pine's high elevation distribution is typically remote from human facilities. On average, management trappings of bears were 6.2 times higher, mortality of adult females 2.3 times higher, and mortality of subadult males 3.3 times higher during years of small seed crops. We hypothesize that high mortality of adult females and subadult males during small seed crop years was a consequence of their tendency to range closest (of all sex-age cohorts) to human facilities; they also had a higher frequency of human habituation compared with adult males. We also hypothesize that low mortality among subadult females during small seed crop years was a result of fewer energetic stressors compared with adult females and greater familiarity with their range compared with subadult males; mortality was low even though they ranged close to humans and exhibited a high frequency of human habituation. Human-habituated and food-conditioned bears were 2.9 times as likely to range within 4 km of developments and 3.1 times as often killed by humans compared with nonhabituated bears. We argue that destruction of habituated bears that use native foods near humans results in a decline in the overall ability of bears to use available habitat; and that the number and extent of human facilities in occupied grizzly bear habitat needs to be minimized unless habituated bears are preserved and successful ways to manage the associated risks to humans are developed.
Article
Microscopic examination of decalcified, sectioned, and stained teeth of three wild known-age black bears (Ursus americanus) shows that the layers present in the cementum may be used for age determination. The data also reveal that the primary factor governing seasonal changes in cementum production, which in turn result in the formation of annuli, may not be denning.
Article
Conventional approaches to studying large mammal habitat selection using radio telemetry may not be feasible in urban environments because of public opposition to trapping, risk of catching nontarget species, restrictions of observer movements, and limited spatial scales. Therefore, I evaluated use of public sightings for determining habitat selection of urban coyotes (Canis latrans) in Seattle, Washington. I used telephone interviews to document coyote sightings from 1988 to 1989. To examine biases in public sightings, I used radio telemetry to investigate habitat selection of coyotes in 1990. Both methods of data collection showed that coyotes were associated (P < 0.05) with forest habitat. Telemetry data revealed that coyotes moved shorter distances (P < 0.001) and remained closer (P = 0.004) to forest habitat during daylight than during night. Public sightings were farther from forest habitat (P < 0.05) than were telemetry data collected during daylight and, to a lesser degree, during night. Public sightings occurred mostly during daylight (93%, P < 0.001) and during summer (63%, P < 0.001), and were biased toward habitats where people were concentrated and coyotes easily seen. However, bootstrap sampling showed that the association between coyotes and forest habitat was unchanged (P greater-than-or-equal-to 0.08) by replacing 20% of actual public sightings with random locations, which suggested that small amounts of random error did not obscure the most important habitat association. In addition, the association between coyotes and forest habitat was the same (P > 0.8) for bootstrap samples of 20, 60, and 108 public sightings, which suggested that small datasets may reveal important habitat associations. Usefulness of public sighting information will depend on identifying sources of bias and research objectives.
Article
The ability of bears (Ursus spp.) to accumulate fat reserves before winter denning is essential to winter survival and successful reproduction. We conducted an experiment to determine if the digestive ability of black bears (U. americanus) changes seasonally. Six captive bears were fed commercial dog food rations and the digestibilities of gross energy and crude protein were determined in August and again in November. Bears showed significantly higher digestion of gross energy and significantly lower digestion of crude protein in November than in August. We suggest that a systemically mediated increase in fat and carbohydrate assimilation, at the expense of protein assimilation, occurs in the fall, and that this is an adaptation facilitating rapid weight gain before denning.
Article
We assessed the effects of increasing human activity on brown bear Ursus arctos use of a salmon spawning stream by comparing observations (865 h) collected 1988–1990 to those (293 h) from 1992 when human activities extended a week later into the fall feeding period (26 August–12 October). We classified individual adult bears according to their tolerance of people as ‘habituated’, or ‘non-habituated’; sub-adults were considered a third behavioural class. In 1992, non-habituated adults (n = 14 of 22 total adults) reduced their activity in apparent response to an extended lodge season, by delaying their use of the river by 17 days. In contrast, habituated adult bear activity remained similar among years, and sub-adult activity increased > four-fold in 1992. We suggest that the human-induced decrease in non-habituated adult activity may have allowed the increased levels of sub-adult activity.
Article
The conservation of wild dogs depends on the persistence of small populations because African wild dog ( Lycaon pictus) populations are low in density, are limited by range loss, and are often restricted to parks containing fewer than 100 adults. Although major limiting factors for wild dog populations have been identified, including interspecific competition and diseases, such factors have not been translated into extinction risk. To assess wild dog extinction risks, we used individual-based simulations constructed from data from a 6-year field study in the Selous Game Reserve, Tanzania. Our simulations predicted that extinction risk for wild dogs was extremely sensitive to competition with lions. Extinction rates ( for periods as short as 20 years) rose sharply to near 1.0 when lion populations exceeded moderate densities (approximately 110–140 lions/1000 km2). This prediction is remarkably consistent with, and highlights, ecological processes that may be responsible for recent patterns of extinction among wild dog populations. Infectious diseases that kill adults, such as rabies, also reduced population persistence if they increased mortality by ≥0.3 and occurred at average intervals of ≤10 years. In contrast, diseases killing only pups, such as canine parvovirus, had weaker effects on persistence. Although persistence declined sharply for mean litter sizes ≤6, persistence was unaffected by increasing mean litter size above its normal range (i.e., 8–12 in Selous). Increasing mean pack size from typical levels reduced extinction risk, but reproductive suppression may set an upper limit on pack size. Although the risk of extinction for 20- to 100-year time frames was appreciable for many realistic ecological and demographic conditions, even low immigration rates substantially increased persistence probabilities. Active management to mitigate the effects of interspecific competition, facilitate dispersal among populations, or augment population size appears essential for wild dog conservation. Resumen: La conservación de perros silvestres depende de la persistencia de poblaciones pequeñas debido a que las poblaciones del perro silvestre africano ( Lycaon pictus) exhiben baja densidad, estan limitados por la périda del rango de distribución y se encuentran frecuentemente restringidos a parques que contienen poco menos de 100 adultos. A pesar de que los factores limitantes principales para las poblaciones de perros silvestres han sido identificadas (e.g., competencia interspecífica y enfermedades), estos factores no han sido traducidos en términos de riesgos de extinción. Para evaluar los riesgos de extinción e perros silvestres, utilizamos simulaciones basadas en individuos, construídas en base a datos de un estudio de campo de seis años en la Reserva Selous Game, en Tanzania. Nuestras simulaciones predicen que el riesgo de extinción para perros silvestres fué extremadamente sensitiva a la competencia con leones. Las tasas de extinción ( por períodos tan cortos como 20 años) se incrementaron rápidamente hasta acercarse a 1.0 cuando las poblaciones de leones excediéron densidades moderadas (∼110–140 leones/1000 km2). Esta predicción es remarcablemente consistente con, y resalta a procesos ecológicos que pueden ser responsables de patrones recientes de extinción entre poblaciones de perros silvestres. Enfermedades infecciosas que aniquilan adultos, como lo es la rabia, también reducen la persistencia poblacional si la mortalidad se incrementa por ≥0.3 y ocurre a intervalos promedio de ≤10 años. En contraste, las enfermedades que atacan solo a cachorros, como lo es el parvovirus canino, tuvo un efecto dénil en la persistencia. Aunque la persistencia disminuye marcadamente en camadas con una media ≤6, la persistencia no fue afectada al incrementarse el tamaño de la camada por arriba de su rango normal (i.e., 8–12 en Selous). Un incremento promedio en el tamaño de la manada por arriba de su tamaño típico redujo el riesgo de extinción, sin embargo, la supresión reproductiva puede establecer un limite máximo en el tamaño de la manada. A pesar de que el riesgo de extinción para bloques de tiempo de 20 a 100 años fue apreciable para varias condiciones ecológicas y demográficas realistas, aún una tasa de inmigración baja incrementa sustaincialmente la probabilidad de persistencia. Un manejo activo para mitigar los efectos de la competencia interspecífica facilita la dispersión entre poblaciones, el aumento en al tamaño poblacional parece ser esencial para la conservación de perros silvestres.
Article
The increase of recreational activities in winter wildlife habitats is of concern because wildlife populations are under considerable stress during winter. To assess the effects of winter activities on black bears Ursus americanus, denning ecology was studied for three winters in the Sierra Nevada and Sweetwater Mountains in Nevada and California. Fourteen bears in the Sierra entered 31 dens earlier and were more selective in their choice of den sites than five Sweetwater bears using 10 dens. Bears at both sites abandoned dens and cubs in response to investigator disturbance, and all but one bear remained active after abandonment. High overlap between bear denning sites and potential winter recreation areas indicated a high potential for den abandonment due to human disturbance. Bear denning areas should be protected from human disturbance during winter.
Article
Thesis (Ph. D.)--University of California, Los Angeles, 1988. Vita. Includes bibliographical references (leaves 76-81). Microfilm. s
Article
Our global impact is finally receiving the scientific attention it deserves. The outcome will largely determine the future course of evolution. Human-modified ecosystems are shaped by our activities and their side effects. They share a common set of traits including simplified food webs, landscape homogenization, and high nutrient and energy inputs. Ecosystem simplification is the ecological hallmark of humanity and the reason for our evolutionary success. However, the side effects of our profligacy and poor resource practices are now so pervasive as to threaten our future no less than that of biological diversity itself. This article looks at human impact on ecosystems and the consequences for evolution. It concludes that future evolution will be shaped by our awareness of the global threats, our willingness to take action, and our ability to do so. Our ability is presently hampered by several factors, including the poor state of ecosystem and planetary knowledge, ignorance of human impact, lack of guidelines for sustainability, and a paucity of good policies, practices, and incentives for adopting those guidelines in daily life. Conservation philosophy, science, and practice must be framed against the reality of human-dominated ecosystems, rather than the separation of humanity and nature underlying the modern conservation movement. The steps scientists can take to imbed science in conservation and conservation in the societal process affecting the future of ecosystems and human well-being are discussed.
Changing dynamics of a population of black bears (Ursus americanus): causes and consequences
  • J P Beckmann
Beckmann, J. P. (2000). Changing dynamics of a population of black bears (Ursus americanus): causes and consequences. PhD thesis, University of Nevada, Reno.
Nevada black bears: ecology, management, and conservation. Nevada Department of Wildlife
  • Goodrich J. M.
Goodrich, J. M. (1993). Nevada black bears: ecology, management, and conservation. Nevada Department of Wildlife. Biol. Bull. No. 11: 1–34.
Wildlife radiotelemetry
  • M D Samuel
  • M R Fuller
Samuel, M. D. & Fuller, M. R. (1994). Wildlife radiotelemetry. In Research and management techniques for wildlife and habitats: 370-418. Bookhout, T. A. (Ed.). Bethesda, MD: Wildlife Society.
A test of radiotelemetry triangulation accuracy in heterogeneous environments
  • Hupp J. W.
Hupp, J. W. & Ratti, J. T. (1983). A test of radiotelemetry triangulation accuracy in heterogeneous environments. Proc. Int. Wildl. Biotele. Conf. 4: 31-46.
Natural Resources Conservation Service, Water and Climate Center
USDA (2002). Natural Resources Conservation Service, Water and Climate Center. Portland: United States Department of Agriculture.
Ecology conservation and management of two western Great Basin black bear populations
  • J M Goodrich