Through the eye of a Gobi khulan – application of camera collars for ecological research of far-ranging species in remote and highly variable ecosystems

The Mongolian Gobi-Eastern Steppe Ecosystem is one of the largest remaining natural drylands and home to a unique assemblage of migratory ungulates. Connectivity and integrity of this ecosystem are at risk if increasing human activities are not carefully planned and regulated. The Gobi part supports the largest remaining population of the Asiatic wild ass (Equus hemionus; locally called “khulan”). Individual khulan roam over areas of thousands of square kilometers and the scale of their movements is among the largest described for terrestrial mammals, making them particularly difficult to monitor. Although GPS satellite telemetry makes it possible to track animals in near-real time and remote sensing provides environmental data at the landscape scale, remotely collected data also harbors the risk of missing important abiotic or biotic environmental variables or life history events. We tested the potential of animal born camera systems (“camera collars”) to improve our understanding of the drivers and limitations of khulan movements. Deployment of a camera collar on an adult khulan mare resulted in 7,881 images over a one-year period. Over half of the images showed other khulan and 1,630 images showed enough of the collared khulan to classify the behaviour of the animals seen into several main categories. These khulan images provided us with: i) new insights into important life history events and grouping dynamics, ii) allowed us to calculate time budgets for many more animals than the collared khulan alone, and iii) provided us with a training dataset for calibrating data from accelerometer and tilt sensors in the collar. The images also allowed to document khulan behaviour near infrastructure and to obtain a day-time encounter rate between a specific khulan with semi-nomadic herders and their livestock. Lastly, the images allowed us to ground truth the availability of water by: i) confirming waterpoints predicted from other analyses, ii) detecting new waterpoints, and iii) compare precipitation records for rain and snow from landscape scale climate products with those documented by the camera collar. We discuss the added value of deploying camera collars on a subset of animals in remote, highly variable ecosystems for research and conservation.

蒙古戈壁-东部草原生态系统是现存规模最大的自然干旱生态系统之一，同时也是独特的迁徙有蹄类动物类群的栖息地。若不对日益增长的人类活动进行审慎规划与监管，该生态系统的连通性与完整性将面临威胁。戈壁区域支撑着现存规模最大的亚洲野驴（Equus hemionus；当地俗称“khulan”）种群。每头khulan的活动范围可达数千平方公里，其移动尺度在陆生哺乳动物中位居前列，这使得对其开展监测的难度极大。尽管GPS卫星遥测技术可实现动物的近实时追踪，遥感技术亦能提供景观尺度的环境数据，但远程采集的数据仍存在遗漏关键非生物、生物环境变量以及生命史事件的风险。我们评估了动物佩戴式摄像项圈（camera collars）在深化我们对khulan活动驱动因素与限制条件认知方面的应用潜力。我们在一头成年雌性khulan身上部署摄像项圈后，于一年内获取了共计7881张影像。其中超半数影像拍摄到了其他khulan，另有1630张影像清晰捕捉到了佩戴项圈的khulan个体，可将记录到的动物行为划分为若干主要类别。这批khulan影像为我们带来了三方面的价值：i）为我们理解关键生命史事件与群体动态提供了全新视角；ii）使我们得以计算远多于佩戴项圈的单一个体的时间预算；iii）为我们提供了用于校准项圈上加速度计与倾斜传感器数据的训练数据集。这些影像还使我们得以记录khulan在人工基础设施附近的行为，并统计得到特定khulan与半游牧牧民及其牲畜之间的日间相遇率。最后，我们还可通过这批影像对水源可获得性进行实地验证：i）证实了通过其他分析预测得到的水源点；ii）发现了全新的水源点；iii）将景观尺度气候产品中记录的雨雪降水数据与摄像项圈采集的相关记录进行了对比。我们讨论了在偏远且环境高度多变的生态系统中，为部分动物个体部署摄像项圈对科研与保护工作的附加价值。