Ungulate movement in an extreme seasonal environment: year-round movement patterns of high-arctic muskoxen
Ungulate movement in an extreme seasonal environment: year-round movement patterns of high-arctic muskoxen
复制标题
极端季节性环境下的有蹄类动物运动：高北极麝牛的全年运动模式
作者：
N. Schmidt;F. M. Beest;J. Mosbacher;Mikkel Stelvig;Lars H. Hansen;J. Nabe‐Nielsen;C. Grøndahl
目前缺乏关于自由放养麝牛Ovibos moschatus运动行为的详细知识。量化个人运动的变化和驱动这种模式的变量对于了解他们如何满足基本要求并为管理提供信息非常重要。由于麝牛存在于营养贫乏的系统中，具有极端的气候和季节性变化，预计个体运动模式在很大程度上取决于环境条件和其中的季节变化。我们分析了在格陵兰东北部（74°28′N，20°34′W）Zackenberg周围漫游的14只成年雌性麝牛的高分辨率位置数据。我们评估了多个外在条件在解释小时速度、转弯角度和活动变化方面的相对重要性（赤池变量权重）。我们发现，一天中的时间，环境温度和土地覆盖类型是最重要的协变量，解释全年细尺度运动和活动模式的变化。移动速度始终较低的土地覆盖类型，更密集的植被。白天较长时，移动速度与环境温度呈正相关，而在日照时间很少或没有日照时，移动速度与温度呈负相关。在运动和活动模式的昼夜高峰观察到的一年中的大部分时间（包括仲冬月份与24小时黑暗），除了在高夏季（24小时的日光），当个人的运动和活动保持持续高。地形的变化（海拔和坡度）只解释了一小部分的麝牛运动模式的变化，在该地区的麝牛观察。对位移模式的分析表明，混合的运动行为。我们的结论是，麝牛在高北极格陵兰岛采取主要是游牧运动的行为，但这样做的一个相当小的地理区域（约5000平方公里），他们的运动和活动模式主要是针对寻找合适的觅食补丁，避免寒冷的压力，在恶劣的冬季天气。
Detailed knowledge on movement behaviour of free-ranging muskoxen Ovibos moschatus is currently lacking. Quantifying variation in individual movement and the variables driving such patterns is important to understand how they meet their basic requirements and to inform management. Because muskoxen exist in nutrient-poor systems with extreme climatic and seasonal variability, individual movement patterns are expected to be largely dependent on environmental conditions and the seasonal variation therein. We analysed high-resolution location data of 14 adult female muskoxen roaming around Zackenberg in northeast Greenland (74°28′N, 20°34′W). We assessed the relative importance (Akaike variable weights) of multiple extrinsic conditions in explaining variation in hourly speed, turning angles, and activity. We found that time of day, ambient temperature, and land cover types were the most important covariates explaining variation in fine-scale movement and activity patterns throughout the year. Movement speeds were consistently lower in land cover types with more dense vegetation. Speed of movement was positively correlated with ambient temperature when the days were long, while negatively related with temperature in periods with few or no hours of daylight. Diurnal peaks in movement and activity patterns were observed most of the year (including mid-winter months with 24-h darkness), except during high-summer (24-h of daylight), when individual movement and activity remained continuously high. The topographic variation (elevation and slope) explained only a small part of the variation in muskox movement patterns in the areas where the muskoxen were observed. Analyses of displacement patterns revealed a mixture of movement behaviours. We conclude that muskoxen in high-arctic Greenland adopt a largely nomadic movement behaviour, but do so within a rather small geographical area (app. 5000 km2), and that their movement and activity patterns are largely directed at finding suitable foraging patches and avoiding cold-stress during harsh winter weather.