MARBEC, UMR IRD-CNRS-UM-IFREMER 9190, Université Montpellier, Montpellier Cedex, France.
School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
Glob Chang Biol. 2020 Dec;26(12):6904-6915. doi: 10.1111/gcb.15389. Epub 2020 Oct 22.
Global change is increasing biotic homogenization globally, which modifies the functioning of ecosystems. While tendencies towards taxonomic homogenization in biological communities have been extensively studied, functional homogenization remains an understudied facet of biodiversity. Here, we tested four hypotheses related to long-term changes (1991-2016) in the taxonomic and functional arrangement of freshwater macroinvertebrate assemblages across space and possible drivers of these changes. Using data collected annually at 64 river sites in mainland New Zealand, we related temporal changes in taxonomic and functional spatial β-diversity, and the contribution of individual sites to β-diversity, to a set of global, regional, catchment and reach-scale environmental descriptors. We observed long-term, mostly climate-induced, temporal trends towards taxonomic homogenization but functional differentiation among macroinvertebrate assemblages. These changes were mainly driven by replacements of species and functional traits among assemblages, rather than nested species loss. In addition, there was no difference between the mean rate of change in the taxonomic and functional facets of β-diversity. Climatic processes governed overall population and community changes in these freshwater ecosystems, but were amplified by multiple anthropogenic, topographic and biotic drivers of environmental change, acting widely across the landscape. The functional diversification of communities could potentially provide communities with greater stability, resistance and resilience capacity to environmental change, despite ongoing taxonomic homogenization. Therefore, our study highlights a need to further understand temporal trajectories in both taxonomic and functional components of species communities, which could enable a clearer picture of how biodiversity and ecosystems will respond to future global changes.
全球变化正在全球范围内增加生物同质性，从而改变生态系统的功能。虽然生物群落的分类学同质化趋势已经得到广泛研究，但功能同质化仍然是生物多样性研究不足的一个方面。在这里，我们检验了四个与淡水大型无脊椎动物群落的分类和功能排列在空间上的长期变化（1991-2016 年）以及这些变化的可能驱动因素相关的假设。我们使用在新西兰大陆的 64 个河流地点每年收集的数据，将分类和功能空间β多样性的时间变化以及个别地点对β多样性的贡献与一组全球、区域、集水区和流域尺度的环境描述符联系起来。我们观察到了长期的、主要是气候驱动的分类学同质化趋势，但大型无脊椎动物群落之间存在功能分化。这些变化主要是由群落之间的物种和功能特征的更替驱动的，而不是嵌套的物种丧失。此外，在β多样性的分类和功能方面的变化率之间没有差异。气候过程控制着这些淡水生态系统中总体的种群和群落变化，但受到多种人为、地形和生物驱动环境变化的放大作用，这些因素在景观中广泛存在。群落的功能多样化可能为群落提供更大的稳定性、抵抗力和恢复力，以应对环境变化，尽管持续的分类学同质化。因此，我们的研究强调需要进一步了解物种群落的分类和功能成分的时间轨迹，这可以更清楚地了解生物多样性和生态系统将如何应对未来的全球变化。
