river system Rivers 9 Ecosystems 5 Biodiversity 3 China 3 river water 3 seasonal variation 3 Aquatic ecosystems 2 Aquatic organisms 2 Monitoring 2 Nutrients 2 River pollution 2 Species richness 2 Water temperatures 2 anthropogenic effect 2 assessment method 2 biodiversity 2 bioindicator 2 Alveolata 1 Anisoptera (dragonflies) 1 Annual cycle 1 Anthropogenic pressures 1 Aquatic carbon indicators 1 Aquatic communities 1 Aquatic habitat 1 Aquatic habitats 1 Aquatic life 1 Assembly 1 Assembly process 1 Bacteria 1