Disentangling the effects of climate change on nature is one of the main challenges facing ecologists nowadays. Warmer climates forces strong effects on lake biota for fish, leading to a reduction in size, changes in diet, more frequent reproduction, and stronger cascading effects. Space-for-time substitution studies (SFTS) are often used to unravel climate effects on lakes biota; however, results from continental lakes are potentially confounded by biogeographical and evolutionary differences, also leading to an overall higher fish species richness in warm lakes. Such differences may not be found in lakes on remote islands, where natural fish free lakes have been subjected to stocking only during the past few hundred years. We studied 20 species-poor lakes located in two remote island groups with contrasting climates, but similar seasonality: the Faroe Islands (cold; 6.5 ± 2.8 °C annual average (SD) and the Azores Islands (warm; 17.3 ± 2.9 °C)). As for mainland lakes, mean body size of fish in the warmer lakes were smaller overall, and phytoplankton per unit of phosphorus higher. The δ¹³C carbon range for basal organisms, and for the whole food web, appeared wider in colder lakes. In contrast to previous works in continental fresh waters, Layman metrics of the fish food web were similar between the two climatic regions. Our results from insular systems provide further evidence that ambient temperatures, at least partially, drive the changes in fish size structure and the cascading effects found along latitude gradients in lakes.

中文翻译：

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岛屿湖泊中的食物网和鱼类大小模式部分支持大陆湖泊中与气候相关的特征

消除气候变化对自然的影响是当今生态学家面临的主要挑战之一。温暖的气候对鱼类的湖泊生物区系产生强烈影响，从而导致尺寸减小，饮食变化，繁殖更加频繁以及连锁效应更强。时空替代研究（SFTS）通常用于揭示气候对湖泊生物区系的影响。但是，大陆湖泊的结果可能会因生物地理和进化差异而混淆，这也导致温暖湖泊中鱼类物种丰富度总体较高。在偏远岛屿的湖泊中可能找不到这种差异，因为这些地区的天然无鱼湖泊仅在过去的数百年中才进行放养。我们研究了位于两个偏远岛屿群中的20个物种贫乏的湖泊，这些湖泊的气候条件相反，但季节性相似：法罗群岛（寒冷；年平均（6.5±2.8°C）和亚速尔群岛（温暖； 17.3±2.9°C））。至于大陆湖泊，总体而言，温度较高的湖泊中鱼类的平均体型较小，而每单位磷中的浮游植物较高。δ在较冷的湖泊中，基础生物和整个食物网的¹³ C碳范围显得更宽。与先前在大陆淡水中所做的工作相比，在两个气候区域之间，鱼类食物网的Layman度量相似。我们从岛屿系统获得的结果进一步证明，环境温度至少部分地驱动了鱼类尺寸结构的变化以及沿湖泊纬度梯度发现的级联效应。