Integration of species traits in direct gradient analysis generates insights into how communities are assembled and may respond to environmental changes. We investigated phytoplankton trait‐environment relationships for over 300 taxa during the open‐water season across 75 north‐temperate lakes and reservoirs in Alberta, Canada. An innovative, data‐driven approach was applied using iterative model selection for RLQ optimization to reveal key monthly associations. Fourth‐corner analysis then tested the significance of relationships using spatially and phylogenetically constrained null models derived by Moran spectral randomization. Both local‐ and regional‐scale drivers of succession were found with evidence of deterministic filtering by traits increasing in mid‐summer. Trait associations to land‐use and water quality highlighted potential anthropogenic cross‐scale interactions, such as logging and pasture development affecting phytoplankton via allochthonous nutrient inputs. Biogeographic factors (e.g., elevation and habitat size) and associated temperature and chemical gradients (e.g., pH and bicarbonate) were also linked to multiple morphological, physiological, and behavioral traits, including potential toxin production. Several correlated traits emphasized importance of trait syndromes corresponding to distinct taxonomic groups (e.g., cyanobacteria and green algae). However, rather than clustering species with shared ecological preferences or roles, our study builds on past trait‐based approaches to phytoplankton by testing for explicit trait associations with a range of environmental factors. Thus, we provide a novel, quantitative means of revealing environmental constraints on communities and translating their compositional changes under climate and other human influences into functional impacts on freshwater ecosystems.

中文翻译：

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量化人类改变景观中浮游植物性状-环境关联的季节性演替

直接梯度分析中物种特征的整合产生了关于社区如何组装以及如何应对环境变化的见解。我们在加拿大艾伯塔省的75个北温带湖泊和水库的淡水季节调查了300多个分类单元的浮游植物性状与环境的关系。一种创新的，数据驱动的方法通过迭代模型选择应用于RLQ优化，以揭示关键的月度关联。然后，第四角分析使用了由Moran光谱随机化推导的空间和系统发育约束的空模型来检验关系的重要性。发现了地方和区域尺度的继承驱动因素，并有证据表明仲夏特征增加了确定性的过滤作用。性状与土地利用和水质的联系突出了潜在的人为跨尺度相互作用，例如伐木和牧场发展通过异源养分输入影响浮游植物。生物地理因素（例如海拔和栖息地面积）以及相关的温度和化学梯度（例如pH和碳酸氢盐）也与多种形态，生理和行为特征相关，包括潜在的毒素产生。几个相关的性状强调了对应于不同分类组（例如，蓝细菌和绿藻）的性状综合症的重要性。但是，我们的研究不是基于具有共同的生态偏好或角色的物种来聚类，而是通过测试与一系列环境因素的显式性状关联，建立在过去基于特征的浮游植物方法上。因此，