Reusch Christine, Gampe Jutta, Scheuerlein Alexander, Meier Frauke, Grosche Lena, Kerth Gerald
Applied Zoology and Nature Conservation, Zoological Institute and Museum University of Greifswald Greifswald Germany.
Max Planck Institute for Demographic Research (MPIDR) Rostock Germany.
Ecol Evol. 2019 Jul 2;9(14):7957-7965. doi: 10.1002/ece3.5292. eCollection 2019 Jul.
Long-lived animals with a low annual reproductive output need a long time to recover from population crashes and are, thus, likely to face high extinction risk, if the current global environmental change will increase mortality rates. To aid conservation of those species, knowledge on the variability of mortality rates is essential. Unfortunately, however, individual-based multiyear data sets that are required for that have only rarely been collected for free-ranging long-lived mammals. Here, we used a five-year data set comprising activity data of 1,445 RFID-tagged individuals of two long-lived temperate zone bat species, Natterer's bats () and Daubenton's bats (), at their joint hibernaculum. Both species are listed as being of high conservation interest by the European Habitats Directive. Applying mixed-effects logistic regression, we explored seasonal survival differences in these two species which differ in foraging strategy and phenology. In both species, survival over the first winter of an individual's life was much lower than survival over subsequent winters. Focussing on adults only, seasonal survival patterns were largely consistent with higher winter and lower summer survival but varied in its level across years in both species. Our analyses, furthermore, highlight the importance of species-specific time periods for survival. Daubenton's bats showed a much stronger difference in survival between the two seasons than Natterer's bats. In one exceptional winter, the population of Natterer's bats crashed, while the survival of Daubenton's bats declined only moderately. While our results confirm the general seasonal survival pattern typical for hibernating mammals with higher winter than summer survival, they also show that this pattern can be reversed under particular conditions. Overall, our study points toward a high importance of specific time periods for population dynamics and suggests species-, population-, and age class-specific responses to global climate change.
年繁殖率低的长寿动物需要很长时间才能从种群崩溃中恢复过来，因此，如果当前的全球环境变化导致死亡率上升，它们很可能面临高灭绝风险。为了帮助保护这些物种，了解死亡率的变异性至关重要。然而，不幸的是，对于自由放养的长寿哺乳动物，很少收集到为此所需的基于个体的多年数据集。在这里，我们使用了一个五年数据集，该数据集包含两种长寿温带蝙蝠物种，纳氏鼠耳蝠（）和道氏鼠耳蝠（）在它们共同的冬眠地1445个带有射频识别标签个体的活动数据。这两个物种都被欧洲栖息地指令列为具有高度保护价值。应用混合效应逻辑回归，我们探究了这两种在觅食策略和物候上存在差异的物种的季节性生存差异。在这两个物种中，个体生命中第一个冬天的存活率远低于随后几个冬天的存活率。仅关注成年个体，季节性生存模式在很大程度上与冬季存活率较高和夏季存活率较低一致，但在这两个物种中，其水平在不同年份有所变化。此外，我们的分析强调了特定物种的生存时间段的重要性。道氏鼠耳蝠在两个季节之间的生存差异比纳氏鼠耳蝠大得多。在一个特殊的冬天，纳氏鼠耳蝠的种群数量崩溃，而道氏鼠耳蝠的存活率仅适度下降。虽然我们的结果证实了冬眠哺乳动物典型的一般季节性生存模式，即冬季存活率高于夏季，但它们也表明这种模式在特定条件下可能会逆转。总体而言，我们的研究指出了特定时间段对种群动态的高度重要性，并表明了对全球气候变化的物种、种群和年龄组特异性反应。
