Fryxell John M, Hazell Megan, Börger Luca, Dalziel Ben D, Haydon Daniel T, Morales Juan M, McIntosh Therese, Rosatte Rick C
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1.
Proc Natl Acad Sci U S A. 2008 Dec 9;105(49):19114-9. doi: 10.1073/pnas.0801737105. Epub 2008 Dec 5.
Recent theory suggests that animals should switch facultatively among canonical movement modes as a complex function of internal state, landscape characteristics, motion capacity, and navigational capacity. We tested the generality of this paradigm for free-ranging elk (Cervus elaphus) over 5 orders of magnitude in time (minutes to years) and space (meters to 100 km). At the coarsest spatiotemporal scale, elk shifted from a dispersive to a home-ranging phase over the course of 1-3 years after introduction into a novel environment. At intermediate spatiotemporal scales, elk continued to alternate between movement modes. During the dispersive phase, elk alternated between encamped and exploratory modes, possibly linked to changes in motivational goals from foraging to social bonding. During the home-ranging phase, elk movements were characterized by a complex interplay between attraction to preferred habitat types and memory of previous movements across the home-range. At the finest temporal and spatial scale, elk used area-restricted search while browsing, interspersed with less sinuous paths when not browsing. Encountering a patch of high-quality food plants triggered the switch from one mode to the next, creating biphasic movement dynamics that were reinforced by local resource heterogeneity. These patterns suggest that multiphasic structure is fundamental to the movement patterns of elk at all temporal and spatial scales tested.
最近的理论表明,动物应根据内部状态、景观特征、运动能力和导航能力等复杂因素,在典型运动模式之间进行灵活切换。我们在时间(从分钟到年)和空间(从米到100公里)的5个数量级上,测试了这种模式在自由放养的麋鹿(Cervus elaphus)中的普遍性。在最粗略的时空尺度上,麋鹿在被引入新环境后的1至3年内,从扩散阶段转变为定居阶段。在中等时空尺度上,麋鹿继续在运动模式之间交替。在扩散阶段,麋鹿在驻留和探索模式之间交替,这可能与动机目标从觅食到社交联系的变化有关。在定居阶段,麋鹿的运动特点是对首选栖息地类型的吸引力与对整个活动范围内先前运动的记忆之间的复杂相互作用。在最精细的时间和空间尺度上,麋鹿在觅食时采用区域限制搜索,不觅食时则穿插着较不曲折的路径。遇到一片优质食物植物会触发从一种模式到另一种模式的切换,形成双相运动动态,这种动态因当地资源的异质性而得到强化。这些模式表明,多相结构对于在所有测试的时空尺度上麋鹿的运动模式至关重要。