Phillips Laura M, Aitkenhead Ian, Janion-Scheepers Charlene, King Catherine K, McGeoch Melodie A, Nielsen Uffe N, Terauds Aleks, Liu W P Amy, Chown Steven L
School of Biological Sciences, Monash University, Victoria 3800, Australia.
Iziko South African Museum, Cape Town 8001, South Africa.
Conserv Physiol. 2020 Jun 15;8(1):coaa049. doi: 10.1093/conphys/coaa049. eCollection 2020.
As global climates change, alien species are anticipated to have a growing advantage relative to their indigenous counterparts, mediated through consistent trait differences between the groups. These insights have largely been developed based on interspecific comparisons using multiple species examined from different locations. Whether such consistent physiological trait differences are present within assemblages is not well understood, especially for animals. Yet, it is at the assemblage level that interactions play out. Here, we examine whether physiological trait differences observed at the interspecific level are also applicable to assemblages. We focus on the Collembola, an important component of the soil fauna characterized by invasions globally, and five traits related to fitness: critical thermal maximum, minimum and range, desiccation resistance and egg development rate. We test the predictions that the alien component of a local assemblage has greater basal physiological tolerances or higher rates, and more pronounced phenotypic plasticity than the indigenous component. Basal critical thermal maximum, thermal tolerance range, desiccation resistance, optimum temperature for egg development, the rate of development at that optimum and the upper temperature limiting egg hatching success are all significantly higher, on average, for the alien than the indigenous components of the assemblage. Outcomes for critical thermal minimum are variable. No significant differences in phenotypic plasticity exist between the alien and indigenous components of the assemblage. These results are consistent with previous interspecific studies investigating basal thermal tolerance limits and development rates and their phenotypic plasticity, in arthropods, but are inconsistent with results from previous work on desiccation resistance. Thus, for the Collembola, the anticipated advantage of alien over indigenous species under warming and drying is likely to be manifest in local assemblages, globally.
随着全球气候变化，预计外来物种相对于本地物种将具有越来越大的优势，这是由两类物种之间持续存在的性状差异介导的。这些见解主要是基于对来自不同地点的多个物种进行的种间比较得出的。对于动物而言，在群落内部是否存在这种一致的生理性状差异，目前还知之甚少。然而，正是在群落层面上，各种相互作用才得以展现。在此，我们研究在种间水平上观察到的生理性状差异是否也适用于群落。我们聚焦于弹尾目昆虫，它是土壤动物群的重要组成部分，在全球范围内均有入侵现象，同时关注与适应性相关的五个性状：临界高温最大值、最小值和范围、抗干燥能力以及卵发育速率。我们检验了以下预测：本地群落中的外来成分比本地成分具有更高的基础生理耐受性或速率，以及更显著的表型可塑性。群落中外来成分的基础临界高温最大值、热耐受性范围、抗干燥能力、卵发育的最适温度、该最适温度下的发育速率以及限制卵孵化成功的上限温度，平均而言均显著高于本地成分。临界低温的结果则存在变数。群落中外来成分和本地成分在表型可塑性方面不存在显著差异。这些结果与先前关于节肢动物基础热耐受性极限和发育速率及其表型可塑性的种间研究一致，但与先前关于抗干燥能力的研究结果不一致。因此，对于弹尾目昆虫来说，在全球变暖及干燥的情况下，外来物种相对于本地物种的预期优势可能会在各地的本地群落中显现出来。
