Biodiv Sci ›› 2023, Vol. 31 ›› Issue (4): 22500.  DOI: 10.17520/biods.2022500

Special Issue: 青藏高原生物多样性与生态安全

• Original Papers: Animal Diversity • Previous Articles     Next Articles

Protozoan community diversity and its impact factor in the middle reaches of the Yarlung Zangbo River in the wet season

Qing Yang1,2, Xiaodong Li1,2, Shengxian Yang1,2, Xin Chao1,2, Huiqiu Liu1,2, Sang Ba1,2,*()   

  1. 1. Laboratory of Tibetan Plateau Wetland and Watershed Ecosystem, School of Ecology and Environment, Tibet University, Lhasa 850000
    2. Center for Carbon Neutrality in the Third Pole of the Earth, Tibet University, Lhasa 850000
  • Received:2022-08-30 Accepted:2022-11-20 Online:2023-04-20 Published:2023-04-20
  • Contact: *E-mail:


Aim: The Yarlung Zangbo River is an important water system in China, and as a high-altitude river in the Tibetan Plateau, its special environmental conditions make its aquatic ecosystem valuable to study. In recent years, studies on the aquatic ecology of the Yarlung Zangbo River have gradually increased, but studies focusing on protozoa are rare. The aim of this study was to explore the community dynamics of protozoa in the middle Yarlung Zangbo River and its driving factors, and to provide basic data and decision-making references for further studies on the Yarlung Zangbo River as well as for the monitoring and conservation of the Tibetan Plateau water environment.

Methods: 18S rDNA high-throughput sequencing technology was used to study the protozoa diversity, and the physicochemical factors were measured on site of water bodies at 28 sample sites in the middle reaches of the Yarlung Zangbo River (Qushui County to Pai Town) in July 2021 (wet season). The α diversity of community was analyzed by Shannon diversity index, Simpson diversity index, Pielou evenness index and richness index; the β diversity of community was analyzed by Jaccard difference index; analysis of the interspecific relationships was analyzed by co-occurrence networks; the influence of physicochemical factors on the diversity of the protozoan community was studied by correlation and bioenvironmental (BIOENV) analysis.

Results: Cercozoa, Ciliophora and Dinoflagellata were dominant on both mainstream and tributary reaches. With regard to community diversity, Shannon diversity was significantly different between the mainstream and tributary reaches; β diversity was dominated by the turnover component in both reaches, and there was a significant distance-decay trend in the protozoan community in both reaches. Protozoan species interactions were dominated by synergism. Electrical conductivity (EC), water temperature (WT), turbidity (TUR), and total nitrogen (TN) were the main environmental factors affecting α diversity of protozoan communities; WT and altitude (ALT) were the main environmental factors affecting β diversity of protozoan communities. The main environmental factors affecting the protozoan communities in the tributaries were pH, WT and ALT combinations, while the main environmental factor affecting the protozoan communities in the mainstream was EC.

Conclusion: Protozoan community diversity in the study area is spatially variable in two reaches of the mainstream and tributaries, β diversity is dominated by turnover components, and community similarity has a clear trend of geographical decay. The mainstream protozoan community is the most stable and sensitive to environmental changes. The dynamic changes in protozoan community diversity are the result of the combined influence of multiple environmental factors.

Key words: Yarlung Zangbo River, protozoa, β diversity decomposition, geographical pattern, physicochemical factors