Xu Kai, Xiao Wenhong, Hu Dazhi, Holyoak Marcel, Ji Chengpeng, Zhang Juntao, Ma Duifang, Xiao Zhishu
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Integr Zool. 2024 Dec 17. doi: 10.1111/1749-4877.12935.
Spatiotemporal interactions between predators and prey are central to maintaining sustainable functioning ecosystems and community stability. For wild ungulates and their predators, livestock grazing is an important anthropogenic disturbance causing population declines and modifying their interactions over time and space. However, it is poorly understood how fine-scale grazing affects the spatiotemporal responses of predators, prey, and their interactions. Two opposing hypotheses describe a dichotomy of possible effects. The human shield hypothesis states that people can protect prey because predators avoid areas with high human-induced mortality risk, whereas in the human competitor hypothesis, humans compete for prey and negatively impact predators through reduced prey availability. We used camera-trapping data from the Gansu Qilianshan National Nature Reserve in Northwest China to measure occupancy, daily activity patterns, and spatiotemporal interactions between snow leopards (Panthera uncia), the dominant predator, and their ungulate prey in areas with contrasting grazing intensities. The results of grazing were consistent with both the human-shield and human-competitor hypotheses, affecting spatiotemporal patterns and interactions of predators and prey. For the primary prey species, blue sheep (Pseudois nayaur), their spatial and temporal patterns were affected by grazing, which led to a reduction in interaction frequencies with snow leopards. For secondary prey, grazing led to reduced interaction frequencies with snow leopards for white-lipped deer (Przewalskium albirostris) and red deer (Cervus yarkandensis), but increased frequencies for alpine musk deer (Moschus chrysogaster). Our results indicate how both competition among livestock and prey and predator or prey avoidance of grazed areas can impact populations and predator-prey interactions. Our findings are relevant to grazing management and snow leopard conservation.
捕食者与猎物之间的时空相互作用对于维持生态系统的可持续功能和群落稳定性至关重要。对于野生有蹄类动物及其捕食者而言，牲畜放牧是一种重要的人为干扰因素，会导致种群数量下降，并随着时间和空间的变化改变它们之间的相互作用。然而，目前人们对精细尺度的放牧如何影响捕食者、猎物的时空反应及其相互作用了解甚少。两种相反的假说描述了可能产生的二分效应。“人类盾牌”假说认为，人类可以保护猎物，因为捕食者会避开人类导致死亡率风险高的区域；而在“人类竞争者”假说中，人类与猎物竞争，并通过减少猎物可利用性对捕食者产生负面影响。我们利用中国西北甘肃祁连山国家级自然保护区的相机陷阱数据，测量了不同放牧强度区域内，作为主要捕食者的雪豹（Panthera uncia）及其有蹄类猎物的占有率、日常活动模式和时空相互作用。放牧结果与“人类盾牌”和“人类竞争者”假说均相符，影响了捕食者和猎物的时空模式及相互作用。对于主要猎物物种岩羊（Pseudois nayaur），其时空模式受到放牧影响，这导致了与雪豹的互动频率降低。对于次要猎物，放牧导致白唇鹿（Przewalskium albirostris）和马鹿（Cervus yarkandensis）与雪豹的互动频率降低，但使高山麝（Moschus chrysogaster）与雪豹的互动频率增加。我们的研究结果表明，牲畜与猎物之间的竞争以及捕食者或猎物对放牧区域的回避，是如何影响种群数量以及捕食者 - 猎物之间的相互作用的。我们的研究结果与放牧管理和雪豹保护相关。
