UMR 6553, Univ Rennes, CNRS, ECOBIO (Ecosystèmes, Biodiversité, Évolution), Rennes, France.
INRAE, Aix-Marseille Université, UMR RECOVER, Aix-en-Provence, France.
Glob Chang Biol. 2022 Oct;28(20):5914-5927. doi: 10.1111/gcb.16338. Epub 2022 Jul 22.
Polar and alpine regions are changing rapidly with global climate change. Yet, the impacts on biodiversity, especially on the invertebrate ectotherms which are dominant in these areas, remain poorly understood. Short-term extreme temperature events, which are growing in frequency, are expected to have profound impacts on high-latitude ectotherms, with native species being less resilient than their alien counterparts. Here, we examined in the laboratory the effects of short periodic exposures to thermal extremes on survival responses of seven native and two non-native invertebrates from the sub-Antarctic Islands. We found that survival of dipterans was significantly reduced under warming exposures, on average having median lethal times (LT ) of about 30 days in control conditions, which declined to about 20 days when exposed to daily short-term maxima of 24°C. Conversely, coleopterans were either not, or were less, affected by the climatic scenarios applied, with predicted LT as high as 65 days under the warmest condition (daily exposures at 28°C for 2 h). The native spider Myro kerguelensis was characterized by an intermediate sensitivity when subjected to short-term daily heat maxima. Our results unexpectedly revealed a taxonomic influence, with physiological sensitivity to heat differing between higher level taxa, but not between native and non-native species representing the same higher taxon. The survival of a non-native carabid beetle under the experimentally imposed conditions was very high, but similar to that of native beetles, while native and non-native flies also exhibited very similar sensitivity to warming. As dipterans are a major element of diversity of sub-Antarctic, Arctic and other cold ecosystems, such observations suggest that the increased occurrence of extreme, short-term, thermal events could lead to large-scale restructuring of key terrestrial ecosystem components both in ecosystems protected from and those exposed to the additional impacts of biological invasions.
极地和高山地区正随着全球气候变化迅速变化。然而，这些变化对生物多样性的影响，特别是对这些地区占主导地位的无脊椎变温动物的影响，仍然知之甚少。短期极端温度事件的频率正在增加，预计这些事件将对高纬度变温动物产生深远影响，本地物种的恢复能力不如外来物种。在这里，我们在实验室中研究了短期极端温度暴露对来自南极岛屿的七种本地和两种非本地无脊椎动物的生存反应的影响。我们发现，在变暖暴露下，双翅目昆虫的存活率显著降低，在对照条件下的平均致死时间 (LT) 约为 30 天，而当暴露于每日短期最高温度 24°C 时，LT 下降到约 20 天。相反，鞘翅目昆虫要么不受气候情景的影响，要么受影响较小，在最温暖的条件下（每天在 28°C 下暴露 2 小时），预测 LT 高达 65 天。本地蜘蛛 Myro kerguelensis 在受到短期每日高温最大值的影响时表现出中等敏感性。我们的结果出人意料地揭示了一种分类影响，即热生理敏感性在高级分类群之间存在差异，但在代表同一高级分类群的本地和非本地物种之间没有差异。在实验条件下，一种非本地的步甲科甲虫的存活率非常高，但与本地甲虫相似，而本地和非本地的苍蝇对变暖也表现出非常相似的敏感性。由于双翅目昆虫是南极、北极和其他寒冷生态系统多样性的主要组成部分，因此这些观察结果表明，极端短期热事件的发生频率增加可能导致关键陆地生态系统组成部分的大规模重组，无论是在免受生物入侵额外影响的生态系统中，还是在暴露于这些影响的生态系统中。
