Connecting diversity and process: Eukaryotic phytoplankton community dynamics across the Yangtze River using environmental DNA
Rivers are collectors of both water and environmental changes in a catchment area, and act as dispersal pathways for biodiversity. But it remains unclear whether, and how strongly, environmental changes and dispersal dynamics shape the phytoplankton communities, especially within large river ecosyst...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Ecological Indicators |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X25009586 |
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| Summary: | Rivers are collectors of both water and environmental changes in a catchment area, and act as dispersal pathways for biodiversity. But it remains unclear whether, and how strongly, environmental changes and dispersal dynamics shape the phytoplankton communities, especially within large river ecosystems. This study utilised environmental DNA (eDNA) to assess how water quality, land use, and geographical distance affect deterministic community assembly processes of eukaryotic phytoplankton across the entire Yangtze River—the world’s third–largest river—in the dry and wet season. We found significant differences in phytoplankton community composition over time and space, with more phyla detected during the dry season, and α diversity increased from upstream to downstream. Generalist species’ composition varied significantly across geographic regions, land use types, and environmental gradients during the wet season, whereas endemic species were primarily affected by local environmental conditions during the dry season. Stochastic processes dominated community assembly during both seasons, with dispersal limitation having a stronger influence than drift, particularly in the dry season. In contrast, deterministic processes had minimal effects, with α diversity showing weak responses to individual factors. By integrating eDNA–based biodiversity data with physicochemical and geospatial factors, we provide a comprehensive view of ecosystem conditions and highlight the need for region-specific conservation strategies in large, human-impacted rivers. It also indicates the predominant role of stochastic processes in shaping phytoplankton communities and suggests further investigation into the effects of hydrological factors. |
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| ISSN: | 1470-160X |