Human‐assisted introductions of exotic species are a leading cause of anthropogenic change in biodiversity; however, context dependencies and interactions with co‐occurring stressors impede our ability to predict their ecological impacts. The legacy of historical sportfish stocking in mountainous regions of western North America creates a unique, natural quasiexperiment to investigate factors moderating invasion impacts on native communities across broad geographic and environmental gradients. Here we synthesize fish stocking records and zooplankton relative abundance for 685 mountain lakes and ponds in the Cascade and Canadian Rocky Mountain Ranges, to reveal the effects of predatory sportfish introduction on multiple taxonomic, functional and phylogenetic dimensions of prey biodiversity. We demonstrate an innovative analytical approach, combining exploratory random forest machine learning with confirmatory multigroup analysis using multivariate partial least‐squares structural equation models, to generate and test hypotheses concerning environmental moderation of stocking impacts. We discovered distinct effects of stocking across different dimensions of diversity, including negligible (nonsignificant) impacts on local taxonomic richness (i.e. alpha diversity) and trophic structure, in contrast to significant declines in compositional uniqueness (i.e. beta diversity) and body size. Furthermore, we found that stocking impacts were moderated by cross‐scale interactions with climate and climate‐related land‐cover variables (e.g. factors linked to treeline position and glaciers). Interactions with physical morphometric and lithological factors were generally of lesser importance, though catchment slope and habitat size constraints were relevant in certain dimensions. Finally, applying space‐for‐time substitution, a strong antagonistic (i.e. dampening) interaction between sportfish predation and warmer temperatures suggests redundancy of their size‐selective effects, meaning that warming will lessen the consequences of introductions in the future and stocked lakes may be less impacted by subsequent warming. While both stressors drive biotic homogenization, our results have important implications for fisheries managers weighing the costs/benefits of stocking—or removing established non‐native populations—under a rapidly changing climate.

中文翻译：

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气候变暖减缓了引进的野鱼对猎物生物多样性的多个方面的影响。

由人类协助引进外来物种是生物多样性人为改变的主要原因。但是，上下文相关性以及与同时发生的压力源的相互作用阻碍了我们预测其生态影响的能力。北美西部山区的历史性鲑鱼种群的遗留下来的遗产创造了独特的自然准实验，以调查在广泛的地理和环境梯度上缓和入侵对当地社区的影响的因素。在这里，我们综合了喀斯喀特山脉和加拿大落基山脉的685个高山湖泊和池塘的鱼类种群记录和浮游动物的相对丰度，以揭示捕食性运动鱼类的引入对猎物生物多样性的多个分类学，功能和系统发育维度的影响。我们展示了一种创新的分析方法，将探索性随机森林机器学习与使用多元偏最小二乘结构方程模型进行的确认性多组分析相结合，以生成和检验与种群影响的环境调节有关的假设。我们发现，在不同的多样性维度上，种群具有明显的影响，包括对当地生物分类学丰富度（即α多样性）和营养结构的影响（微不足道）（与之相比），在组成上的独特性（即β多样性）和体型显着下降的情况下。此外，我们发现，与气候以及与气候相关的土地覆盖变量（例如与林木位置和冰川相关的因素）的跨尺度相互作用，减轻了种群影响。与物理形态学和岩性因素的相互作用通常不太重要，尽管集水坡度和生境大小限制在某些方面是相关的。最后，应用时空替代，在运动鱼捕食和温度升高之间强烈的拮抗（即减弱）相互作用表明它们的大小选择效应是多余的，这意味着温度升高将减轻将来引入的后果，并且放养的湖泊可能受后续变暖影响较小。尽管两个压力源都推动了生物同质化，但我们的结果对渔业管理者在快速变化的气候下权衡放养的成本/收益（或去除已建立的非本地种群）的影响具有重要意义。鲑鱼捕食和温度升高之间的相互作用表明它们的大小选择效应是多余的，这意味着温度升高将减轻将来引入鱼类的后果，而随后的温度升高对放养湖泊的影响较小。尽管两个压力源都推动了生物同质化，但我们的结果对渔业管理者在快速变化的气候下权衡放养的成本/收益（或去除已建立的非本地种群）的影响具有重要意义。鲑鱼捕食和温度升高之间的相互作用表明它们的大小选择效应是多余的，这意味着温度升高将减轻将来引入鱼类的后果，而随后的温度升高对放养湖泊的影响较小。尽管两个压力源都推动了生物同质化，但我们的结果对渔业管理者在快速变化的气候下权衡放养的成本/收益（或去除已建立的非本地种群）的影响具有重要意义。