Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke- Str. 17, 10315 Berlin, Germany.
Institute for Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195 Berlin, Germany.
Biol Lett. 2020 Sep;16(9):20200351. doi: 10.1098/rsbl.2020.0351. Epub 2020 Sep 23.
Many migratory species have shifted their geographic distribution in response to climate change, yet the underlying mechanisms are poorly understood, particularly for mammals. We hypothesized that generational shifts are underlying the observed colonization of hibernation sites further north in a migratory bat, the common noctule (. To evaluate our hypothesis, we collected long-term data on the migratory status and demography of common noctules in a recently colonized hibernation area. Based on isotopic data of 413 individuals, we observed a significant decline in the proportion of long-distance migrants from 2004 to 2015 for both sexes and across all age groups. Demographic data collected between 2007 and 2016 from 3394 individuals demonstrated that subadult males were more abundant during the early colonization stage, followed by a gradual shift to a more balanced age and sex composition. Our results suggest that the colonization of hibernacula at higher latitudes is promoted by generational shifts, involving mostly first-year males. Generational shifts seem to be a likely mechanism for distribution changes in other bats and potentially also in other mammals.
许多迁徙物种为了应对气候变化已经改变了它们的地理分布，但其中的潜在机制还不太清楚，特别是对于哺乳动物。我们假设，在迁徙蝙蝠——普通夜鹰（Common Noctule）中，代际更替是导致其在冬眠地进一步向北迁徙的原因。为了验证我们的假设，我们收集了一个新被占领的冬眠地区中普通夜鹰的迁徙状况和种群动态的长期数据。基于 413 个个体的同位素数据，我们观察到 2004 年至 2015 年间，两性和所有年龄段的长距离迁徙者的比例都显著下降。2007 年至 2016 年间，我们从 3394 个个体中收集的种群动态数据表明，在早期的殖民阶段，亚成体雄性更为丰富，随后逐渐向更平衡的年龄和性别结构转变。我们的研究结果表明，代际更替（主要涉及第一年的雄性）促进了高纬度冬眠地的殖民化。代际更替似乎是其他蝙蝠，以及其他哺乳动物分布变化的一个可能机制。
