Mori Tomoki, Mori Saki N, Izumiyama Shigeyuki
Institute for Mountain Science Shinshu University Minami-minowa, Kami-Ina Japan.
Present address: Research Center for Wildlife Management Gifu University Gifu Japan.
Ecol Evol. 2024 Jul 9;14(7):e11562. doi: 10.1002/ece3.11562. eCollection 2024 Jul.
Foraging plays a vital role in the survival of wildlife, and shifts in food availability can impact species fitness and survival. Ursids are known to consume a wide variety of foods and are known to be opportunistic omnivores. Consequently, seasonal shifts in diet, which correspond to temporal and spatial shifts in the availability of food resources, have long captivated researchers studying the foraging behavior of Ursidae. Nevertheless, comprehensive dietary studies encompassing both the population and individual levels remain scarce. In this study, we investigated the dietary patterns of Asiatic black bears () at both the population and individual levels, using data collected through GPS collars and field surveys of individual bear scat samples in Nagano Prefecture, Japan, from 2016 to 2020. From early April to late June, bears mainly foraged on green vegetation. During this period, male and large-bodied female bears showed a strong preference for green vegetation. Small-bodied female bears also ate mostly green vegetation but tended to consume more fruit than other bears towards the end of this period. From June to October, bears' diets included a substantial amount of fruit, with notable peaks in fruit consumption in late June and early September. During the summer months, female bears often incorporated social insects into their diet compared to the population-level trend. In mid-September, the consumption of seeds from the Fagaceae family surged, becoming the primary dietary component during this period. This trend was consistently observed across the population. These findings underscore the importance conducting in-depth dietary analyses that take into account individual characteristics such as sex, age, and body weight.
觅食对野生动物的生存起着至关重要的作用，食物可获得性的变化会影响物种的适应性和生存。熊科动物已知会食用多种食物，是机会主义杂食动物。因此，与食物资源可获得性的时空变化相对应的季节性饮食变化，长期以来一直吸引着研究熊科动物觅食行为的研究人员。然而，涵盖种群和个体层面的全面饮食研究仍然稀缺。在本研究中，我们利用2016年至2020年在日本长野县通过GPS项圈收集的数据以及对单个熊粪便样本的实地调查，在种群和个体层面上调查了亚洲黑熊的饮食模式。从4月初到6月底，熊主要以绿色植物为食。在此期间，雄性和体型较大的雌性熊对绿色植物表现出强烈的偏好。体型较小的雌性熊也大多以绿色植物为食，但在这段时间结束时，它们比其他熊更倾向于食用更多的水果。从6月到10月，熊的饮食中包含大量水果，6月下旬和9月初水果消费量出现显著峰值。在夏季，与种群层面的趋势相比，雌性熊经常将社会性昆虫纳入它们的饮食中。9月中旬，壳斗科种子的消费量激增，成为这一时期的主要饮食成分。这一趋势在整个种群中都得到了一致观察。这些发现强调了进行深入饮食分析的重要性，这种分析要考虑到性别、年龄和体重等个体特征。
