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Activity patterns of the Asiatic black bear in the Russian Far East based on camera-trap data
Sergey A. Kolchin, Aleksey Yu. Oleynikov, Evgeniia V. Volkova, Galina P. Salkina
Ursus 2025 (36e6), 1-16, (27 May 2025) https://doi.org/10.2192/URSUS-D-23-00024R1
KEYWORDS: activity patterns, Asiatic black bear, camera-trapping, daily activity, Russia, seasonal activity, Sikhote-Alin Mountains, Ursus thibetanus ussuricus
Species’ activity patterns are driven by the need to meet basic requirements such as food, social interactions, movement, and rest. A variety of biotic and abiotic factors often influence these behaviors. From 2011 to 2021 we used camera-trap data to describe and compare the seasonal and daily activity patterns of the relatively poorly studied Asiatic black bear (Ursus thibetanus) across 2 study areas on the western and eastern macro slopes of the Sikhote-Alin Ridge (Russia) with differing climate characteristics. We analyzed data from 2,396 independent photo-records, including 225 near denning trees during hibernation. We used a Relative Abundant Index (RAI) for seasonal activity analysis and kernel density estimator based on the time of independent photographic events to calculate the proportion of diurnal, crepuscular, and nocturnal activity of each study area and period. Bears were active on average from 2 April to 3 November on the western macro slope and from 24 March to 8 November on the eastern one, which amounted to 59% and 63% of the year, respectively. Males stayed in dens for 5 months, whereas females with cubs used denning sites for up to 6.5 months. Winter activity was observed on the milder eastern slope (RAI = 0.09) during nut- and acorn-abundant seasons. The mean RAI during the active period for all sexes and ages (Apr–Oct) was 2.6, peaking in September (RAI = 4.8) and August (RAI = 4.3), correlating with feeding and fruit ripening. We compared daily activity patterns for different types of camera-trap locations and found that there were no significant differences (activity overlap coefficient Δ4 varied from 0.81 to 0.93). Daily activity varied across calendar seasons, peaking from 07:00 hours to 19:00 hours. Diurnal activity was predominant (79.73%), with notable crepuscular activity in autumn (19.96%) and winter (21.74%). Nocturnal activity did not differ significantly between seasons. Significant overlap in daily activity was observed between warm and cold seasons (Δ4 = 0.78). The indicators we obtained can be used as a basis for further monitoring the well-being of the Asiatic black bear population at the northern border of the range.
Denning black bear response to anthropogenic disturbance and implications for cub survival in Florida
Darcy Doran-Myers, Kaili Gregory, Conor P. McGowan, Vanessa Hull, Brian K. Scheick
Ursus 2025 (36e7), 1-20, (27 May 2025) https://doi.org/10.2192/URSUS-D-24-00011R1
KEYWORDS: American black bear, anthropogenic, cub, den, disturbance, Florida, hibernation, management, prescribed fire, research, survival, Ursus americanus
Open Access Article
Wildlife research and management can be disruptive to wildlife. By advancing our understanding of the impacts of these activities, we can reduce adverse effects, improve decision-making, and enhance the outcomes of research and management. During 2017–2019, we observed the responses of denning female American black bears (Ursus americanus) to 3 types of routine research and management activities in Florida, USA: (1) a low-level, nonintrusive human approach near the natal den (n H 44); (2) a high-level, intrusive human approach involving cub handling (n H 42); and (3) a prescribed burn within 1 km of the den during the denning season (n H 11). We measured responses (flight distance, time away, and postdisturbance denning behavior) using Global Positioning System collars programmed to record a location every 2 hours. We observed minimal response from bears to low-level human disturbances. In contrast, all bears fled after high-level human disturbances, with responses ranging from staying nearby throughout the disturbance and quickly returning to cubs, to fleeing several kilometers and abandoning cubs. On average, bears fled approximately 380 m from the den and returned to their cubs 7 hours postdisturbance. After returning, most bears relocated their cubs to a new den site, on average 125 m away. Responses to prescribed fire ranged from no measurable response and no den relocation to den site abandonment with cub mortality. Through generalized linear modeling, we found that adult female time away was positively associated with cub age. We found that annual cub survival was negatively associated with fire exposure in the den and with continued denning at a disturbed den site following high-level disturbance. In areas where bears are easily displaced from dens, these results provide insights that may improve bear research and habitat management decisions.