PDF(Pubmed)
Abstract：
Parturition and the early neonatal period are critical life history stages in ungulates with considerable implications for population growth and persistence. Understanding the changes in behaviour induced by ungulate parturition is important for supporting effective population management, but reliably identifying birth sites and dates presents a challenge for managers. Rocky Mountain bighorn sheep (Ovis canadensis canadensis) are one such highly valued and ecologically important species in montane and subalpine ecosystems of Western North America. In the face of changing patterns of anthropogenic land use, wildlife managers increasingly require site-specific knowledge of the movement and habitat selection characteristics of periparturient sheep to better inform land use planning initiatives and ensure adequate protections for lambing habitat. We used movement data from GPS collared parturient (n = 13) and non-parturient (n = 8) bighorn sheep in Banff National Park, Canada to (1) identify lambing events based on changes in key movement metrics, and (2) investigate how resource selection and responses to human use change during the periparturient period. We fit a hidden Markov model (HMM) to a multivariate characterization of sheep movement (step length, daily home range area, residence time) to predict realistic lambing dates for the animals in our study system. Leave-one-out cross validation of our model resulted in a 93% success rate for parturient females. Our model, which we parameterized using data from known parturient females, also predicted lambing events in 25% of known non-parturient ewes in a test dataset. Using a latent selection difference function and resource selection functions, we tested for postpartum changes in habitat use, as well as seasonal differences in habitat selection. Immediately following lambing, ewes preferentially selected high-elevation sites on solar aspects that were more rugged, closer to escape terrain, and further from roads. Within-home range habitat selection was similar between individuals in different reproductive states, but parturient ewes had stronger selection for low snow depth, sites closer to barren ground, and sites further from trails. We propose that movement-based approaches such as HMMs are a valuable tool for identifying critical parturition habitat in species with complex movement patterns and may have particular utility in study areas without access to extensive field observations or vaginal implant transmitters. Furthermore, our results suggest that managers should minimize human disturbance in lambing areas to avoid interfering with maternal behaviour and ensure access to a broad range of suitable habitat in the periparturient period.
摘要：
分娩和新生儿早期是有蹄类动物的关键生活史阶段，对人口增长和持久性有重要影响。了解有蹄类动物分娩引起的行为变化对于支持有效的人口管理很重要，但是可靠地确定出生地点和日期对管理者来说是一个挑战。落基山大角羊（Oviscanadensiscanadensis）是北美西部山地和亚高山生态系统中具有重要价值和生态意义的物种之一。面对人为土地利用模式的变化，野生动物管理者越来越需要特定地点的围产期绵羊的运动和栖息地选择特征知识，以更好地为土地利用规划举措提供信息，并确保对羔羊栖息地的充分保护。我们使用了班夫国家公园的GPS领产妇（n=13）和非产妇（n=8）大角羊的运动数据，加拿大(1)根据关键运动指标的变化来识别羔羊事件，(2)调查围产期资源选择和对人类使用的反应是如何变化的。我们将隐马尔可夫模型(HMM)拟合到绵羊运动的多变量表征(步长，每日家庭范围，停留时间）来预测我们研究系统中动物的真实产仔日期。我们模型的一次交叉验证对产妇的成功率为93％。我们的模型，我们使用已知产妇的数据对其进行参数化，还预测了测试数据集中25％的已知非产妇母羊的羔羊事件。使用潜在选择差异函数和资源选择函数，我们测试了产后栖息地使用的变化，以及栖息地选择的季节性差异。在羔羊之后，母羊优先选择更坚固的太阳方面的高海拔地点，更接近逃生地形，离道路更远。在不同生殖状态的个体之间，家庭范围内的栖息地选择相似，但是产妇母羊对低积雪深度的选择更强，靠近贫瘠土地的地点，和远离小径的地点。我们建议，基于运动的方法，如HMM是识别具有复杂运动模式的物种的关键分娩栖息地的有价值的工具，并且可能在研究领域具有特殊的实用性，而无需获得广泛的野外观察或阴道植入物发射器。此外，我们的结果表明，管理者应尽量减少产仔区的人为干扰，以避免干扰产妇的行为，并确保在围产期进入广泛的合适栖息地。
