Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China.
Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia.
Nat Ecol Evol. 2023 Mar;7(3):347-354. doi: 10.1038/s41559-022-01967-w. Epub 2023 Jan 23.
Many studies have documented the average body size of animals declining over time. Compared to mean body size, less is known about long-term changes in intraspecific trait variation (ITV), which is also important to understanding species' ability to cope with environmental challenges. On the basis of 393,499 specimen records from 380 species collected in North America between 1880 and 2020, we found that body size ITV increased by 9.59% for mammals (n = 302) and 30.67% for birds (n = 78); human-harvested species had higher probability of ITV increase. The observed increasing ITV in many species suggests possible niche expansion and potential buffering effects against downsizing but it risks increased maladaptation to rapidly changing environments. The results demonstrate that trait mean and variance do not necessarily respond in similar ways to anthropogenic pressures and both should be considered.
许多研究都记录了动物的平均体型随时间缩小的现象。与平均体型相比，种内特征变异（Intraspecific trait variation，ITV）的长期变化知之甚少，但这对于了解物种应对环境挑战的能力也很重要。本研究基于 1880 年至 2020 年间在北美采集的 380 个物种的 393499 个样本记录，发现哺乳动物（n=302）和鸟类（n=78）的体型 ITV 分别增加了 9.59%和 30.67%；人类采集的物种 ITV 增加的可能性更高。许多物种 ITV 的增加表明可能存在生态位扩张和潜在的缓冲效应，以对抗体型缩小，但这也可能导致对快速变化的环境的适应不良风险增加。结果表明，特征的平均值和方差不一定会以相似的方式对人为压力做出反应，两者都应加以考虑。
