UMR 5023, LEHNA, Biodiversité et Plasticité dans les Hydrosystèmes, Bât Forel RDC, 6 rue Raphaël Dubois, Université Lyon 1, 69100 Villeurbanne, France.
UMR 5023, LEHNA, Biodiversité et Plasticité dans les Hydrosystèmes, Bât Forel RDC, 6 rue Raphaël Dubois, Université Lyon 1, 69100 Villeurbanne, France.
Sci Total Environ. 2017 Dec 1;599-600:1912-1921. doi: 10.1016/j.scitotenv.2017.05.057. Epub 2017 May 21.
Understanding natural temporal changes in Mediterranean rivers with contrasting flow regimes in relation to those of temperate rivers may prove helpful in predicting effects of climate change on aquatic biodiversity.
We aimed to compare temporal variability in taxonomic and trait compositions of nearly natural rivers in two climatic regions with varying flow regimes to address the effects of future climate changes on aquatic biodiversity in reference conditions.
We analysed taxonomic and biological trait compositions using the Foucard multivariate method to compare within-site temporal variability levels and the evolution of within-date spatial variability patterns. In addition, we assessed the effects of temporal variability levels on taxonomic and functional diversity and on community specialization.
Our results reveal (i) highly fluctuating environments of the Mediterranean region, particularly in intermittent rivers, which lead to higher levels of temporal variability in both taxonomic and trait compositions of benthic invertebrate assemblages, with marked synchrony in Mediterranean streams linked to contrasting flow characteristics; (ii) higher degrees of taxonomic richness associated with higher levels of functional diversity in Mediterranean rivers relative to temperate rivers, (iii) higher temporal stability for functional diversity and trait compositions of benthic invertebrate assemblages than for taxonomic richness and compositions; and (iv) a recovery of all diversity metrics following drying events in intermittent sites.
This study offers insight into a rarely addressed question concerning the temporal variability of trait compositions in benthic invertebrate assemblages among rivers differing in terms of flow regimes. It suggests that temperate rivers will experience higher levels of temporal variability in terms of taxonomic and trait compositions under future climatic change scenarios, even in sites that will remain perennial, resulting in higher levels of taxonomic and functional diversity. This lack of temporal stability in least-disturbed situations should be taken into account when developing bioassessment tools based on reference conditions.
了解具有不同流动模式的地中海河流与温带河流的自然时间变化，可能有助于预测气候变化对水生生物多样性的影响。
我们旨在比较两个气候区具有不同流动模式的近自然河流中分类和特征组成的时间变异性，以解决未来气候变化对参考条件下水生生物多样性的影响。
我们使用 Foucard 多变量方法分析分类和生物特征组成，以比较站点内时间变异性水平和日期内空间变异性模式的演变。此外，我们评估了时间变异性水平对分类和功能多样性以及群落特化的影响。
我们的结果表明：（i）地中海地区的环境波动很大，特别是间歇性河流，导致底栖无脊椎动物群落的分类和特征组成的时间变异性水平更高，与对比鲜明的流动特征相关的地中海溪流具有明显的同步性；（ii）与温带河流相比，地中海河流的分类丰富度与功能多样性的相关性更高；（iii）与分类丰富度和组成相比，功能多样性和底栖无脊椎动物群落特征组成的时间稳定性更高；（iv）在间歇性站点发生干涸事件后，所有多样性指标都得到了恢复。
这项研究提供了一个关于在流动模式不同的河流中底栖无脊椎动物群落特征组成的时间变异性的很少被关注的问题的见解。它表明，即使在保持常年流动的地点，温带河流在未来的气候变化情景下，在分类和特征组成方面将经历更高水平的时间变异性，从而导致更高水平的分类和功能多样性。在基于参考条件的生物评估工具的开发中，应该考虑到在最不受干扰的情况下缺乏时间稳定性的情况。
