Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK.
Department of Biosciences, College of Science, Swansea University, Swansea, SA2 8PP, UK.
Ecol Lett. 2018 Jul;21(7):1001-1009. doi: 10.1111/ele.12965. Epub 2018 Apr 15.
Demographic senescence is increasingly recognised as an important force shaping the dynamics of wild vertebrate populations. However, our understanding of the processes that underpin these declines in survival and fertility in old age remains limited. Evidence for age-related changes in foraging behaviour and habitat use is emerging from wild vertebrate studies, but the extent to which these are driven by within-individual changes, and the consequences for fitness, remain unclear. Using longitudinal census observations collected over four decades from two long-term individual-based studies of unmanaged ungulates, we demonstrate consistent within-individual declines in home range area with age in adult females. In both systems, we found that within-individual decreases in home range area were associated with increased risk of mortality the following year. Our results provide the first evidence from the wild that age-related changes in space use are predictive of adult mortality.
人口老龄化正日益被视为塑造野生动物种群动态的重要力量。然而，我们对于支撑这些老年时期生存和生育能力下降的过程的理解仍然有限。来自野生动物研究的证据表明，在觅食行为和栖息地利用方面存在与年龄相关的变化，但这些变化在多大程度上是由个体内部变化驱动的，以及对适应性的影响仍不清楚。利用两个长期基于个体的未管理有蹄类动物研究在过去四十年中收集的纵向普查观测数据，我们证明了成年雌性个体的家域面积随年龄的增长而持续下降。在这两个系统中，我们发现个体的家域面积减少与下一年的死亡率增加有关。我们的研究结果提供了野生环境中第一个证据，表明与年龄相关的空间利用变化可以预测成年动物的死亡率。
