1. Arctic freshwaters support biota adapted to the harsh conditions at these latitudes, but the climate is changing rapidly and so are the underlying environmental filters. Currently, we have limited understanding of broad-scale patterns of Arctic riverine biodiversity and the correlates of α- and β-diversity.
2. Using information from a database set up within the scope of the Arctic Council's Conservation of Arctic Flora and Fauna Circumpolar Biodiversity Monitoring Plan, we analysed patterns and correlates of α- and β-diversity in benthic diatom and macroinvertebrate communities across northern Norway, Sweden, and Finland. We analysed variation in total β-diversity and its replacement and richness difference components in relation to location of the river reach and its drainage basin (Baltic Sea in the south, the Barents Sea in the east and the north, and the Norwegian Sea in the west), in addition to climate and environmental variables.
3. In both macroinvertebrates and diatoms, the replacement and richness difference components showed wide variation. For macroinvertebrates, the richness difference component was the more important, whereas for diatoms, the replacement component was the more important in contributing to variation in β-diversity. There was no significant difference in β-diversity between the three main drainage basins, but species composition differed among the drainage basins.
4. Based on the richness difference component of β-diversity, climate variables were most strongly associated with community variation in macroinvertebrates. In diatoms, both environmental and climate variables were strongly correlated with community compositional variation. In both groups, there were also significant differences in α-diversity among the three main drainage basins, and several taxa were significant indicators of one of these drainage basins. Alpha diversity was greater in areas with a continental climate, while the oceanic areas in the west harboured greatly reduced flora and fauna.
5. The correlates of biodiversity were relatively similar in macroinvertebrates and diatoms. Climate variables, in particular temperature, were the most strongly associated with biodiversity patterns in the Arctic rivers of Fennoscandia. Sedimentary geology may be associated with increased productivity and, to a lesser extent, with sensitivity to acidification. There was considerable variation in community composition across Arctic Fennoscandia, indicating the necessity of protecting several stream reaches or even whole catchments within each region to conserve total riverine biodiversity. Furthermore, it is likely that the predicted changes in temperature in Arctic areas will influence riverine diversity patterns across Fennoscandia.

中文翻译：

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北极 Fennoscandia 河流硅藻和大型无脊椎动物 α 和 β 多样性的生态相关性

1. 北极淡水支持适应这些纬度恶劣条件的生物群，但气候正在迅速变化，潜在的环境过滤器也在迅速变化。目前，我们对北极河流生物多样性的广泛模式以及α-和β-多样性的相关性了解有限。
2. 利用在北极理事会北极动植物保护北极圈极地生物多样性监测计划范围内建立的数据库中的信息，我们分析了挪威北部、瑞典和瑞典北部底栖硅藻和大型无脊椎动物群落 α 和 β 多样性的模式和相关性芬兰。我们分析了总 β 多样性及其替代和丰富度差异分量与河流河段及其流域（南部波罗的海、东部和北部的巴伦支海以及挪威海的流域）位置的变化。西），除了气候和环境变量。
3. 在大型无脊椎动物和硅藻中，替换和丰富度差异成分表现出很大的变化。对于大型无脊椎动物，丰富度差异成分更为重要，而对于硅藻，替代成分对β多样性变化的贡献更为重要。三个主要流域之间的β多样性没有显着差异，但流域之间的物种组成存在差异。
4. 基于 β 多样性的丰富度差异分量，气候变量与大型无脊椎动物群落变异的相关性最强。在硅藻中，环境和气候变量都与群落组成变化密切相关。在两组中，三个主要流域的α多样性也存在显着差异，其中几个分类群是其中一个流域的重要指标。大陆性气候地区的阿尔法多样性更大，而西部海洋地区的动植物群大大减少。
5. 在大型无脊椎动物和硅藻中，生物多样性的相关性相对相似。气候变量，特别是温度，与芬诺斯坎迪亚北极河流中的生物多样性模式最密切相关。沉积地质可能与生产力提高有关，并且在较小程度上与酸化敏感性有关。整个北极 Fennoscandia 的群落组成存在相当大的差异，这表明有必要保护每个区域内的几个河流河段甚至整个集水区，以保护整个河流生物多样性。此外，北极地区预测的温度变化很可能会影响整个芬诺斯坎迪亚的河流多样性模式。