Losing seasonal patterns in a hibernating omnivore? Diet quality proxies and faecal cortisol metabolites in brown bears in areas with and without artificial feeding

Sergiel, Agnieszka; Barja, Isabel; Navarro-Castilla, Álvaro; Zwijacz‐Kozica, Tomasz; Selva, Nuria

doi:10.1371/journal.pone.0242341

Cited by 16 publications

(24 citation statements)

References 86 publications

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“…Bras , ov city was visited by 629,132 tourists in 2017 and by 659,311 tourists in 2018 [38], which may help explain the large number of HBCs registered. Although during the winter season, brown bears generally hibernate [55], and food intake is low [78], in Brașov, a rather high rate of HBC is recorded, due to the active presence of humans through winter tourism, the area being one of the main centres of winter tourism in Romania. Here, the ski season opens in the second half of December and closes at the end of March or in the beginning of April.…”

Section: Discussionmentioning

confidence: 99%

Patterns of Human–Brown Bear Conflict in the Urban Area of Brașov, Romania

Cimpoca

Voiculescu

2022

Sustainability

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Human–bear conflicts are increasing in number due to deforestation, urban expansion, tourism, and habitat invasion by humans. Our study was conducted in Brașov, a picturesque city in central Romania. Brașov is surrounded by forests and has significant tourist traffic, but also much uncollected garbage and many garbage containers, which attract brown bears. We recorded human–bear conflicts in four districts (Răcădău, the Historic Centre, Noua, and Gară) between 2004 and 2018, finding 55 cases in total, of which in 19 cases involving people, 4 people were killed and 32 were injured. In 36 cases, there were no human victims. We mapped the locations of human–bear conflicts and garbage containers, then analysed their space–time location and human victims in terms of behavioural factors. The altitudes at which brown bears were identified ranged from 580 to 790 m, whereas bears were found in the city at distances of between 100 and 2600 m from the forest. The highest frequency of human–bear conflicts occurred during summer and autumn, and the most common behavioural factor was human outdoor activities. This study provides an important background for understanding human–bear conflicts and will help local authorities develop effective strategies to reduce human–bear conflicts and mitigate risk.

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Section: Discussionmentioning

confidence: 99%

Patterns of Human–Brown Bear Conflict in the Urban Area of Brașov, Romania

Cimpoca

Voiculescu

2022

Sustainability

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“…Bears exhibit a roam-to-mate behavior (Steyaert et al 2012), thus both sexes increase their home ranges, and consequently road crossings during mating. Home ranges decrease during post-mating for both male and females without cubs (Dahle and Swenson 2003) and re-increase during hyperphagia (de Gabriel Hernando et al 2020), when individuals become again more mobile in order to locate suitable resources, store fat and ultimately prepare for denning and reproduction (Ordiz et al 2016;Sergiel et al 2020). However, the two sexes do not cross roads equally (Sawaya et al 2014) and crossing intensity changes seasonally (Guthrie 2012).…”

Section: Discussionmentioning

confidence: 99%

Exploring 15 years of brown bear (Ursus arctos)-vehicle collisions in northwestern Greece

Psaralexi¹,

Lazarina²,

Mertzanis³

et al. 2022

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Road networks provide several benefits to human societies; however, they are also one of the major drivers of fragmentation and habitat degradation. Their negative effects include wildlife-vehicle collisions which are associated with increased barrier effects, restricted gene flow, and increased local extinction risk. Large carnivores, such as the brown bear (Ursus arctos), are vulnerable to road mortality while they also put human safety at risk in every collision. We recorded approximately 100 bear-vehicle collisions during the last 15 years (2005–2020) in northwestern Greece and identified common aspects for collisions, i.e., spatial, or temporal segregation of collision events, road features, and age or sex of the involved animals. We recorded collisions in both the core distribution area of brown bears, as well as at the periphery, where few individuals, mostly males, disperse. According to our findings, there are four collision hotspots which include ca. 60% of total collisions. Bear-vehicle collisions occurred mostly in periods of increased animal mobility, under poor light conditions and low visibility. In most cases, we deem that a collision was unavoidable at the time of animal detection, because the driver could not have reacted in time to avoid it. Appropriate fencing, in combination with the retention of safe passages for the animals, can minimize collisions. Therefore, such mitigation measures, wildlife warning signs and other collision prevention systems, such as animal detection systems, should be adopted to decrease the number of bear-vehicle collisions and improve road safety.

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“…Diet composition, food availability and abundance are the most influential factors identifiable through FGs in free-ranging Asiatic black (Malcolm et al, 2014), brown (Sergiel et al, 2020a), American black (Stetz et al, 2013;Wasser et al, 2004) and grizzly bears (Stetz et al, 2013;von der Ohe et al, 2004;Wasser et al, 2004). Characteristically, diets composed solely of coarse plant matter such as grasses gave rise to higher levels of FG when compared to mixed diets of proteins and berries, an effect which was more pronounced as seasons progressed towards winter (Sergiel et al, 2020a;Stetz et al, 2013;von der Ohe et al, 2004). Whilst this was initially attributed to high fibre content corresponding to decreased intestinal reabsorption of steroid hormones due to increased gut transition times (Lewis et al, 1997;von der Ohe et al, 2004), Stetz et al (2013) concluded this effect more likely related to nutritional impacts on circulating GCs.…”

Section: Measuring Long-term Stress In Free-ranging Bearsmentioning

confidence: 99%

Evaluation of physiological stress in free‐ranging bears: current knowledge and future directions

et al. 2022

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Stress responses, which are mediated by the neurogenic system (NS) and hypothalamic–pituitary–adrenal (HPA) axis help vertebrates maintain physiological homeostasis. Fight‐or‐flight responses are activated by the NS, which releases norepinephrine/noradrenaline and epinephrine/adrenaline in response to immediate stressors, whilst the HPA axis releases glucocorticoid hormones (e.g. cortisol and corticosterone) to help mitigate allostatic load. There have been many studies on stress responses of captive animals, but they are not truly reflective of typical ranges or the types of stressors encountered by free‐ranging wildlife, such as responses and adaptation to environmental change, which are particularly important from a conservation perspective. As stress can influence the composition of age and sex classes of free‐ranging populations both directly and indirectly, ecological research must be prioritised towards more vulnerable taxa. Generally, large predators tend to be particularly at risk of anthropogenically driven population declines because they exhibit reduced behavioural plasticity required to adapt to changing landscapes and exist in reduced geographic ranges, have small population sizes, low fecundity rates, large spatial requirements and occupy high trophic positions. As a keystone species with a long history of coexistence with humans in highly anthropogenic landscapes, there has been growing concern about how humans influence bear behaviour and physiology, via numerous short‐ and long‐term stressors. In this review, we synthesise research on the stress response in free‐ranging bear populations and evaluate the effectiveness and limitations of current methodology in measuring stress in bears to identify the most effective metrics for future research. Particularly, we integrate research that utilised haematological variables, cardiac monitors and Global Positioning System (GPS) collars, serum/plasma and faecal glucocorticoid concentrations, hair cortisol levels, and morphological metrics (primarily skulls) to investigate the stress response in ursids in both short‐ and long‐term contexts. We found that in free‐ranging bears, food availability and consumption have the greatest influence on individual stress, with mixed responses to anthropogenic influences. Effects of sex and age on stress are also mixed, likely attributable to inconsistent methods. We recommend that methodology across all stress indicators used in free‐ranging bears should be standardised to improve interpretation of results and that a wider range of species should be incorporated in future studies.

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Losing seasonal patterns in a hibernating omnivore? Diet quality proxies and faecal cortisol metabolites in brown bears in areas with and without artificial feeding

Cited by 16 publications

References 86 publications

Patterns of Human–Brown Bear Conflict in the Urban Area of Brașov, Romania

Patterns of Human–Brown Bear Conflict in the Urban Area of Brașov, Romania

Exploring 15 years of brown bear (Ursus arctos)-vehicle collisions in northwestern Greece

Evaluation of physiological stress in free‐ranging bears: current knowledge and future directions

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