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<p>Large carnivores such as the brown bear (<i>Ursus arctos</i>) are keystone species whose persistence is increasingly threatened by habitat fragmentation, human encroachment, and climate change. Among the most vulnerable demographic groups are females with dependent cubs, whose survival strategies remain poorly understood in human-dominated landscapes. We investigated the fine-scale spatial and temporal ecology of female brown bears with cubs compared to solitary adults in the Alborz–Hyrcanian region of northern Iran. Using 22 camera-trap stations over 3,461 trap-nights in Kiasar National Park and Dodangeh Wildlife Sanctuary, we recorded 381 independent bear detections, including 40 events involving females with 57 cubs. Temporal activity analyses based on the Delta (Δ) overlap index revealed broadly bimodal activity patterns in both groups, with peaks in the morning (04:00–08:00) and late afternoon (16:00–20:00). However, females with cubs showed sharper declines in activity after the morning peak and markedly reduced temporal overlap with most native large mammals (Δ difference = 0.2–0.6), and especially with domestic livestock (Δ = 0.65 vs. 0.79 for solitary bears), indicating active avoidance during peak grazing periods. MacKenzie occupancy models indicated that females with cubs had approximately 28% lower occupancy (ψ = 0.565) and 34% lower detection probability than solitary bears, consistent with smaller and more selective home ranges. Generalized linear models identified co-occurrence with solitary bears and domestic livestock as positive predictors of female presence with cubs, whereas red deer presence was negatively associated; solitary bear occurrence was best predicted by wild boar abundance and greater distance from villages. This study suggests that female brown bears with cubs use spatial and temporal strategies to reduce competitive and human-related risks, often within smaller, more selective areas that may overlap with livestock. While further research is needed, identifying and prioritizing these critical maternal habitats for protection along with implementing seasonal livestock restrictions could be key to improving cub survival and long-term population viability in increasingly fragmented landscapes.</p>

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Spatiotemporal patterns of brown bears with cubs compared to lone bears

  • 期刊论文

  • 发表日期：

    2025年11月8日

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  • Mehdi Tizrouyan,
  • Farid Salmanpour,
  • Kaveh Ateni Mofrad,
  • Panteha Ardani,
  • Eshagh Sadati,
  • Omid Hedayatpour,
  • Mohsen Yasari,
  • Amirhosein Gohardehi,
  • Mahan Salmanpour

摘要

Large carnivores such as the brown bear (Ursus arctos) are keystone species whose persistence is increasingly threatened by habitat fragmentation, human encroachment, and climate change. Among the most vulnerable demographic groups are females with dependent cubs, whose survival strategies remain poorly understood in human-dominated landscapes. We investigated the fine-scale spatial and temporal ecology of female brown bears with cubs compared to solitary adults in the Alborz–Hyrcanian region of northern Iran. Using 22 camera-trap stations over 3,461 trap-nights in Kiasar National Park and Dodangeh Wildlife Sanctuary, we recorded 381 independent bear detections, including 40 events involving females with 57 cubs. Temporal activity analyses based on the Delta (Δ) overlap index revealed broadly bimodal activity patterns in both groups, with peaks in the morning (04:00–08:00) and late afternoon (16:00–20:00). However, females with cubs showed sharper declines in activity after the morning peak and markedly reduced temporal overlap with most native large mammals (Δ difference = 0.2–0.6), and especially with domestic livestock (Δ = 0.65 vs. 0.79 for solitary bears), indicating active avoidance during peak grazing periods. MacKenzie occupancy models indicated that females with cubs had approximately 28% lower occupancy (ψ = 0.565) and 34% lower detection probability than solitary bears, consistent with smaller and more selective home ranges. Generalized linear models identified co-occurrence with solitary bears and domestic livestock as positive predictors of female presence with cubs, whereas red deer presence was negatively associated; solitary bear occurrence was best predicted by wild boar abundance and greater distance from villages. This study suggests that female brown bears with cubs use spatial and temporal strategies to reduce competitive and human-related risks, often within smaller, more selective areas that may overlap with livestock. While further research is needed, identifying and prioritizing these critical maternal habitats for protection along with implementing seasonal livestock restrictions could be key to improving cub survival and long-term population viability in increasingly fragmented landscapes.