有蹄类昼夜活动时空动态——以岩羊(Pseudois nayaur)为例

调整时间分配和空间利用是有蹄类应对食物资源和环境胁迫周期性波动的常见生存策略。为探索高山有蹄类对这种波动的行为响应和策略，于2018年6月-2019年8月利用红外相机对四川王朗国家级自然保护区内的岩羊（Pseudois nayaur）种群进行了调查，并利用Wilcoxon秩和检验初步分析了它们的昼夜活动时空动态（所涉及分析的数据监测时间为2018年7月底至2019年8月初）。基于前人的研究结论和观点，预测岩羊的昼夜活动在不同季节和不同空间类型将呈现显著差异。结果表明，岩羊的行为基本符合预测：（1）岩羊夏季昼间和冬季夜间较多出现在林缘（夏季昼间：43.64±3.39；冬季夜间：10.00±0.26）和林内（夏季昼间：34.21±3.21，P=0.065；冬季夜间：8.40±0.64，P=0.026），可能与躲避极端气温有关；（2）岩羊在食物较匮乏的冬季，夜间的活动强度均显著高于其他季节（冬季：23.00±0.73；春季：2.00±0.39；夏季：4.80±1.36；秋季：15.00±1.31），且在昼间选择易于觅食的草甸生境内活动（林缘：31.79±3.54，草甸：22.79±3.16；P=0.081）。有趣的是，岩羊冬季夜间更多选择林缘（10.00±0.26），而非预期的林内生境（8.40±0.64，P=0.026）。岩羊在夜宿地附近（林缘）活动强度最大可能是权衡食物和环境胁迫的结果。因为，夜间集中在距离夜宿地和觅食地都比较近的环境中活动，无疑是一种经济的选择。随着近年来气候变化的加剧，高山生态系统受到的威胁越来越明显。基于本研究的发现，建议更多关注高山物种的生存状况和高山生态系统的健康程度，为认识和评价气候变化对生物多样性的影响提供参考。

A preliminary analysis on the spatio-temporal dynamic of ungulate's circadian activities: a case study of Bharal (Pseudois nayaur)

To cope with periodic fluctuations of food resources and environmental stress, it is a common strategy of ungulates by adjusting their time allocation and space use accordingly. In order to investigate alpine ungulates'' responses and strategies to these fluctuations, we deployed 29 camera-traps in the habitat of Bharal (Pseudois nayaur), in Wanglang National Nature Reserve, Sichuan Province, from June 2018 to August 2019. We analyzed the spatio-temporal dynamic of Bharal''s circadian activities by using Wilcoxon rank sum test in R 3.5.3. According to habitat selection theory and pertinent research, we predicted that Bharal would represent different behavior patterns at the circadian rhythm in facing varied space and time. The results showed that the behavior of Bharal was generally consistent with our predictions. In the first place, during summer daytime and winter night, Bharal was more active in forest edge (summer daytime: 43.64±3.39; winter night: 10.00±0.26) and forest interior (summer daytime: 34.21±3.21, P=0.065; winter night: 8.40±0.64, P=0.026), a possible response to the stress of extreme temperatures in the open meadows. In the second place, during the winter with limited food availability, the night activity intensity of Bharal was significantly higher than that in other seasons (winter: 23.00±0.73; spring: 2.00±0.39; summer: 4.80±1.36; autumn: 15.00±1.31). While in the daytime, more activities were observed in meadow (forest edge: 31.79±3.54, meadow: 22.79±3.16; P=0.081). Different from our expectations, we found Bharal was most active within forest edge (10.00±0.26), than forest interior (8.40±0.64, P=0.026) during winter night. Facing severe environment conditions (low temperature and scarce food), Bharal need to invest more time in foraging and feeding to maintain their energy balance. As a consequence, we believe Bharal chose space close to both food and shelter during winter night when food shortage incompatible, which is the most likely explanation for their behavior pattern during winter night. With the rapid changes of global climate during the past decades, the alpine ecosystems have been seriously threatened. Therefore, we suggest government agencies, societies and researchers pay more attentions to the survival condition of alpine fauna and flora and the stability of the ecosystems. Thereby, there''s no doubt about that further researches will provide us increasing knowledge to understand and evaluate the impacts of climate changes on biodiversity.