Data from: Strong divergence in trait means but not in plasticity across hatchery and wild populations of sea-run brown trout Salmo trutta

There is ample evidence that organisms adapt to their native environment when gene flow is restricted. However, evolution of plastic responses across discrete environments is less well examined. We studied divergence in means and plasticity across wild and hatchery populations of sea-run brown trout (Salmo trutta) in a common garden experiment with two rearing environments (hatchery and a nearly natural experimental stream). Since natural and hatchery environments differ, this arrangement provides an experiment in contemporary adaptation across the two environments. A QST-FST approach was used to investigate local adaptation in survival and growth over the first summer. We found evidence for divergent selection in survival in one year and in body length in both years and rearing environments. In general, the hatchery populations had higher survival and larger body size in both environments. QST in body size did not differ between the rearing environments and constitutive divergence in the means was in all cases stronger than divergence in the plastic responses. These results suggest that in this system constitutive changes in mean trait values are more important for local adaptation than increased plasticity. In addition, ex-situ rearing conditions induce changes in trait means that are adaptive in the hatchery, but potentially harmful in the wild, suggesting that hatchery rearing is likely to be a sub-optimal management strategy for trout populations facing selection in the stream environment.已有充分研究证实，当基因流受限之时，生物会逐步适应其原生栖息环境。然而，针对不同离散环境下的可塑性响应演化，相关研究仍相对不足。本研究依托设置两种饲养环境（孵化场环境与近自然实验溪流）的共同花园实验（common garden experiment），针对野生与孵化场养殖的溯河褐鳟（Salmo trutta）种群，探究其性状均值与可塑性层面的分化情况。鉴于自然环境与孵化场环境存在显著差异，该实验设计可用于探究两种环境下的当代适应性演化过程。本研究采用QST-FST分析方法，探究了首个夏季内存活率与生长性状的本地适应性特征。研究结果显示，某一年份的存活率以及两年间各饲养环境下的体长均存在歧化选择信号。总体而言，孵化场养殖种群在两种饲养环境中均展现出更高的存活率与更大的个体体长。不同饲养环境下的体型QST值并无显著差异，且所有场景中，性状均值的组成型分化均强于可塑性响应层面的分化。上述结果表明，在本研究体系中，相较于可塑性提升，性状均值的组成型改变对本地适应性的贡献更为显著。此外，迁地饲养条件会诱导性状均值发生改变：这类改变在孵化场环境中具有适应性，但在野生环境中却可能产生危害。这表明，对于溪流环境中存在选择压力的鳟鱼种群而言，孵化场养殖或许并非最优的管理策略。