Abstract Understanding the effects of climate change on ecosystem structure and stability is challenging, especially in high latitude regions that are predicted to experience the largest increases in ambient temperature. Global warming is likely to be a key driver of ecosystem change in freshwater lakes. Increased temperature can positively or negatively affect lake community composition through the loss of cold-adapted taxa and the arrival of temperate or eurytopic taxa. Here, we analyse the likely effects of temperature-induced changes in taxonomic richness and compositional turnover of environmentally-sensitive chironomids (Diptera: Chironomidae) across three regions - northern North America, Norway, and Russia - using existing datasets. Structural parameters (beta diversity, compositional disorder, and network skewness) were applied to model-simulated and empirical chironomid datasets across a large spatial temperature gradient. The analyses of empirical datasets showed changes in community structure across temperature gradients, suggesting varying states of ecosystem stability or instability. The comparison with null models enabled assessment as to whether these stresses agreed with expected patterns due to covarying summer temperature conditions or whether they deviated from expectations suggesting additional stress on the ecosystems. For all three regions, lakes in the mid-temperature range showed most evidence of relative ecosystem stability, with greater beta diversity, compositional disorder, and skewness, unanticipated by the modelled simulations. This is most likely due to more diverse habitats across the ecotone boundaries and additional factors that can influence ecosystem structures. Thus, we show that structural changes typical for ecosystem stability can be detected through changes in community structure across temperature gradients. This is important for understanding how lakes may change under current and future climate change.

中文翻译：

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作为高纬度湖泊摇蚊群落稳定性指标的结构变化指标

摘要 了解气候变化对生态系统结构和稳定性的影响具有挑战性，特别是在预计环境温度升高幅度最大的高纬度地区。全球变暖可能是淡水湖泊生态系统变化的主要驱动因素。温度升高可以通过冷适应类群的丧失和温带或深地类群的到来对湖泊群落组成产生积极或消极的影响。在这里，我们使用现有数据集分析了温度引起的环境敏感摇蚊科（双翅目：摇蚊科）的分类丰富度变化和成分转换的可能影响 - 北美北部、挪威和俄罗斯。结构参数（β多样性、成分紊乱、和网络偏度）被应用于跨大空间温度梯度的模型模拟和经验摇蚊数据集。对经验数据集的分析表明，随着温度梯度的变化，群落结构发生了变化，表明生态系统稳定或不稳定的不同状态。与空模型的比较能够评估这些压力是否与由于夏季温度条件共变导致的预期模式一致，或者它们是否偏离了对生态系统造成额外压力的预期。对于所有三个区域，中等温度范围内的湖泊显示出相对生态系统稳定性的大部分证据，具有更大的 Beta 多样性、成分紊乱和偏度，这是建模模拟未预料到的。这很可能是由于跨生态带边界的栖息地更加多样化，以及可能影响生态系统结构的其他因素。因此，我们表明，生态系统稳定性的典型结构变化可以通过跨温度梯度的群落结构变化来检测。这对于了解湖泊在当前和未来气候变化下如何变化很重要。