St. Petersburg Federal Research Center of the Russian Academy of Sciences, Institute of Limnology RAS, Laboratory of Hydrobiology, 9, Sevastyanova st., St. Petersburg 196105, Russia.
University of Public Service, Faculty of Water Sciences, Bajcsy-Zsilinszky utca 12-14, H-6500 Baja, Hungary.
Sci Total Environ. 2022 Feb 10;807(Pt 2):150891. doi: 10.1016/j.scitotenv.2021.150891. Epub 2021 Oct 9.
Although metacommunity dynamics of lentic phytoplankton are relatively well-documented, studies on the role of environmental and spatial processes in shaping phytoplankton communities of large rivers are still scarce. Here, we examined six phytoplankton data sets, which were collected in 1978-2017 from large river-scale segments (mean spatial extent 1117 km) in the Danube River. Our aim was to elucidate role of climatic, spatial and temporal predictors in variation of phytoplankton beta diversity using variance partitioning for compositions of species and functional groups sensu Reynolds. We hypothesised that phytoplankton beta diversity (measured as average distance to group centroid) would be positively related to both climatic heterogeneity and spatial extent used as a proxy for dispersal limitation. Additionally, we tested alternative dispersal models to evaluate different spatial processes structuring phytoplankton community. Our results revealed that spatial variables were more important than climatic factors in controlling both species and functional group composition. Climatic heterogeneity showed significant positive relationship with beta diversity. In contrast, there was no significant relationship between beta diversity and spatial extent, suggesting that spatial effect on beta-diversity was attenuated by anthropogenic disturbance. The better performance of non-directional model compared to model of water directionality suggested that spatial dynamics of phytoplankton metacommunity was in large part regulated by differences in the regional species pools. Spatial and temporal variables outperformed environmental (including climatic) factors in explaining phytoplankton metacommunity structure, indicating that phytoplankton exhibited strong biogeographical patterns. Thus, dispersal limitation interfered with species-sorting processes in determining phytoplankton community structure. In conclusion, our findings revealed that the development of a more reliable bioassessment program of the Danube River should be based on separation into basin regions.
尽管池塘浮游植物的后生动物群动态已得到相对充分的记录，但关于环境和空间过程在塑造大型河流浮游植物群落方面的作用的研究仍然很少。在这里，我们检查了六个浮游植物数据集，这些数据集是 1978-2017 年从多瑙河大河流域段（平均空间范围为 1117 公里）收集的。我们的目的是阐明气候、空间和时间预测因子在浮游植物β多样性变化中的作用，方法是使用方差分解来分析物种和功能组的组成，方法是 Reynolds。我们假设浮游植物β多样性（以组质心的平均距离衡量）与气候异质性和作为扩散限制替代物的空间范围呈正相关。此外，我们测试了替代扩散模型，以评估不同的空间过程对浮游植物群落结构的影响。我们的结果表明，空间变量比气候因素更能控制物种和功能组的组成。气候异质性与β多样性呈显著正相关。相比之下，β多样性与空间范围之间没有显著关系，这表明空间对β多样性的影响因人为干扰而减弱。非定向模型的性能优于水方向模型，这表明浮游植物后生动物群的空间动态在很大程度上受到区域物种库差异的调节。空间和时间变量在解释浮游植物后生动物群结构方面优于环境（包括气候）因素，这表明浮游植物表现出强烈的生物地理格局。因此，扩散限制干扰了物种分类过程，从而决定了浮游植物群落结构。总之，我们的研究结果表明，开发更可靠的多瑙河生物评估计划应基于流域区域的分离。
