The establishment of widespread non-native species and the loss of native species driven by multiple anthropogenic disturbances have led to a dramatic reconfiguration of current biodiversity. Trends towards homogenization or differentiation of fish fauna due to the impact of both introductions and extirpations on the taxonomic facet of biodiversity have been observed worldwide, while such effects on the phylogenetic facet have seldom been quantified. Here, we measured the spatio-temporal changes in taxonomic and phylogenetic dissimilarities of fish assemblages among 12 mainstream reaches of the Lancang River against the background of large-scale cascaded dam construction. We found that both the taxonomic and phylogenetic structures of fish assemblages exhibited heterogeneity due to the reduction in the distribution area of common native species and imbalanced invasion by non-native species, which resulted from habitat fragmentation caused by the large-scale cascaded dam construction. Furthermore, changes in taxonomic and phylogenetic dissimilarities were highly correlated. Patterns of fish assemblage based on both taxonomic and phylogenetic structures showed clear spatio-temporal differences due to the imbalance of regional changes, namely, small changes upstream and large changes downstream. This study revealed that taxonomic and phylogenetic dissimilarities could increase in dam-fragmented habitats via imbalanced native species loss and non-native species invasion. Therefore, the risk of a generally positive interpretation of taxonomic and phylogenetic differentiation is highlighted, which should be highly important to ecologists and conservationists.

中文翻译：

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大型梯级大坝建设推动澜沧江鱼类群落分类和系统发育分化

广泛存在的非本地物种的建立和多种人为干扰导致本地物种的丧失，导致了当前生物多样性的巨大重构。由于引入和灭绝对生物多样性分类学方面的影响，鱼类群的同质化或分化趋势已在世界范围内观察到，而这种对系统发育方面的影响很少被量化。在这里，我们测量了大型梯级大坝建设背景下澜沧江 12 个干流河段鱼类群落分类学和系统发育差异的时空变化。我们发现，由于大规模梯级大坝建设导致栖息地破碎化，常见本地物种分布面积减少和非本地物种入侵不平衡，鱼类组合的分类学和系统发育结构均表现出异质性。此外，分类学和系统发育差异的变化高度相关。由于区域变化的不平衡，即上游小变化和下游大变化，基于分类和系统发育结构的鱼类组合模式表现出明显的时空差异。这项研究表明，通过不平衡的本地物种损失和非本地物种入侵，大坝破碎栖息地的分类学和系统发育差异可能会增加。所以，