Abstract: Carnivores is a key functional group in the ecosystem.Under the situation of global decline of large mammal populations,determining the interspecific interaction and co-existing mechanism between sympatric predators is essential to help us understand the underlying mechanisms driving ecosystem changes and species population dynamics.The spatial and temporal niches are the two most critical dimensions shaping an animal's ecological niche,and the interaction relationship of spatiotemporal niche between sympartric species is the basis to understand species co-existence.In this study,we took the Wolong National Nature Reserve in central Qionglai Mountains,Sichuan Province,as our study area.We collected spatiotemporal data of snow leopard(Panthera uncia,occurrence locations n=198) and red fox(Vulpes vulpes,n=68) from camera-trapping and fecal DNA surveys to construct species distribution models and conduct analysis on their daily activity patterns for both species.The results showed that,the area of overlapped suitable habitats of snow leopard and red fox in the study region was 404.08 km²,which mainly located in the high-altitude area in the northwest part of the reserve,accounting for 77.74% and 80.79% of the total habitat area of snow leopard and red fox respectively.These two species had great overlap on vertical distributions as well and both showed a distribution peak approximately at 4 300 m above sea level,whereas the mean elevation of snow leopard was slightly higher than that of red fox,and the range of red fox's vertical distribution spanned slightly wider than that of snow leopard.The daily activity patterns of snow leopard(number of independent detections n=351) and red fox(n=155) were both bimodal.Snow leopards tended to be crepuscular,while red foxes were more nocturnal,with high level of overlap between the two species(Δ=0.68).At sites where snow leopards were present or where snow leopards had been previously detected within two weeks,red foxes increased their nocturnality,thus reducing the temporal overlap with snow leopards,although their daily activity pattern was not significantly changed.The results of this study preliminarily revealed the spatiotemporal niche relationship between snow leopard and red fox,which will provide examples and basic information for us to better understand the co-existing mechanism of apex predators and meso-predators in alpine ecosystems,and provide supports for the fine management of these carnivore populations in the nature reserves.

Key words: Apex predator, Meso-carnivore, Ecological niche, Interspecific relationship, Camera-trapping, Species distribution model, Daily activity pattern

摘要： 食肉动物是生态系统中关键的功能类群，探究顶级捕食者和次级捕食者的种间作用和共存机制有助于我们深入理解生态系统变化和物种种群动态变化的驱动机制，是目前全球大型兽类种群衰退背景下的重要议题。在动物物种生态位的诸多维度中，空间与时间生态位是其中最为关键的两个维度，了解同域分布物种之间在时、空生态位上的相互关系是探究物种共存机制的基础。本研究以邛崃山脉中部的卧龙国家级自然保护区为研究区域，使用红外相机技术与粪便DNA技术在区内的高山生境开展野外调查，收集雪豹（Panthera uncia，分布点数量n=198）与赤狐（Vulpes vulpes，n=68）的分布数据，分别使用MaxEnt物种分布模型和日活动模式分析来探究区内雪豹和赤狐在时、空生态位上的相互作用关系。结果显示，在空间上，研究区域内雪豹和赤狐的潜在适宜分布区重叠面积404.08 km²，主要集中在保护区西北部的高海拔区域，分别占二者适宜栖息地总面积的77.74%和80.79%，重叠程度较高；在垂直分布上，区内雪豹分布的平均海拔较赤狐稍高，赤狐的海拔分布范围较雪豹稍广，但两物种在垂直方向上的重叠程度也较高，均在海拔4 300 m左右出现分布高峰。在时间生态位上，雪豹（独立探测数n=351）与赤狐（n=155）的日活动模式均为双峰型，雪豹偏向晨昏性而赤狐更偏向夜行性，整体上二者日活动节律重叠度较高（Δ=0.68）；在有雪豹活动的位点上以及两周内曾有雪豹活动的情况下，赤狐会加强夜间活动，降低其日活动节律与雪豹之间的重叠程度，但其日活动模式未有显著改变。本研究的结果初步揭示了雪豹与赤狐的时空生态位关系，将为深入理解高山生态系统中顶级捕食者与次级捕食者的共存机制提供实例与基础信息，同时也将为保护区针对这些食肉动物种群的精细化管理提供支持。

关键词: 顶级捕食者, 中级食肉动物, 生态位, 种间关系, 红外相机, 物种分布模型, 日活动节律