Author(s): Xinyi Zhou; Xiongdong Zhou; Jiahao Zhang; Chubin Weng And Xu Mengzhen

Linked Author(s):

Keywords: The Jinsha River; The Xiangjiaba dam; Zooplankton; Environmental DNA; Community assembly

Abstract: Hydropower development has a profound impact on river ecosystems worldwide. The construction of dams significantly alters hydrological, hydrodynamic, and water quality conditions, thereby affecting the distribution and diversity of aquatic organisms. However, previous research has yet to fully understand the mechanisms by which dams drive the assembly of aquatic communities and the formation, maintenance, and variation of biodiversity. By utilizing environmental DNA (eDNA) technology, this study investigated the impact of the Xiangjiaba dam on driving the diversity and community assembly of zooplankton in the lower Jinsha River. The results indicate that the Xiangjiaba significantly alters the α-diversity of zooplankton in this region. Species richness (Chao1) and phylogenetic diversity (PD) in the downstream mainstem (DM) are significantly higher than those in the upstream mainstem (UM), and the diversity along the mainstem decreases as it approaches the dam. The dominant zooplankton groups exhibit significant differences in various water bodies, with protozoa having the highest relative abundance in the DM, while copepods dominate in the upstream tributaries (UT). Under the influence of species compositions and interaction strengths, the network structures in the DM and UT are more complex and robust compared to that in the UM, demonstrating stronger stability for the zooplankton communities. Deterministic processes are the primary drivers of zooplankton community assembly in this region, particularly driving the differentiation of communities upstream and downstream of the dam. Hydrodynamic (e. g., water depth and flow velocity) and water quality conditions (e. g., water temperature and turbidity) have significant effects on the community. Overall, the construction and operation of the Xiangjiaba dam have a complex impact on zooplankton communities: on one hand, they lead to a decrease in α-diversity in near-dam local section; on the other hand, they promote the differentiation of zooplankton communities at the river-segment scale, driving the formation and variation of zooplankton diversity at larger landscape.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2053-cd

Year: 2025