DATASET.xlsxUrbanization drives adaptation to cyanobacterial blooms in zooplankton grazers

Understanding how species and populations respond to urbanization is a crucial topic of contemporary evolutionary biology and has substantial practical relevance for biodiversity conservation. Eutrophication and subsequent cyanobacterial blooms due to rapid urbanization are reshaping aquatic ecosystems and altering biological evolution. In an integrated multivariate approach that addresses morphological and life history traits, we tested the hypotheses that zooplankton grazers inhabiting more urbanized waters had become more tolerant to urban cyanobacterial blooms through adaptive evolution. We also quantified the relative importance of phenotypic plasticity, evolution of mean trait values (constitutive evolution), and evolution of phenotypic plasticity to total trait changes under urbanization using a reaction norm approach. We found that urban grazers have genetically adapted to urban cyanobacterial bloom, which is due primarily to selection for reduced cyanobacteria-induced phenotypic plasticity in urban eutrophic conditions. The evolution of plasticity has been instrumental in driving alterations across multiple traits. Our experiment provides strong support for contemporary adaptive evolution under urbanization, and highlighted the importance of quantifying genetic variation in phenotypic plasticity when evaluating drivers and mechanism of population evolution in cities.

探究物种与种群对城市化的响应机制，是当代进化生物学的核心议题，同时对生物多样性保护具有重要的现实意义。快速城市化引发的水体富营养化（eutrophication）及后续蓝藻水华（cyanobacterial blooms），正在重塑水生生态系统（aquatic ecosystems）并改变生物演化进程。本研究采用涵盖形态学性状（morphological traits）与生活史性状（life history traits）的整合多元分析方法（integrated multivariate approach），验证了如下假说：栖息于城市化程度更高水域的浮游动物牧食者（zooplankton grazers）已通过适应性进化（adaptive evolution）获得了对城市蓝藻水华的更强耐受能力。本研究同时采用反应规范分析法（reaction norm approach），量化了表型可塑性（phenotypic plasticity）、性状均值进化（即组成型进化（constitutive evolution））以及表型可塑性进化对城市化背景下总性状变化的相对贡献度。研究结果表明，城市生境中的牧食性浮游动物已对城市蓝藻水华产生了遗传适应性，这一适应主要源于城市富营养化环境下针对蓝藻诱导的表型可塑性降低的选择作用。表型可塑性的进化在驱动多性状改变的过程中发挥了关键作用。本实验为城市化背景下的当代适应性进化提供了强有力的支持，并强调了在评估城市种群演化的驱动因素与机制时，量化表型可塑性遗传变异（genetic variation）的重要性。