Biodiv Sci ›› 2020, Vol. 28 ›› Issue (12): 1570-1580.DOI: 10.17520/biods.2019390

• Original Papers • Previous Articles    

Beta diversity of stream bacteria in Hengduan Mountains: The effects of climatic and environmental variables

Mingjia Li1,2, Kaiyuan Wu1,3, Fanfan Meng1,2, Ji Shen1,2, Yongqin Liu2,4, Nengwen Xiao5,*(), Jianjun Wang1,2,*()   

  1. 1. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008
    2. University of Chinese Academy of Sciences, Beijing 100049
    3. School of Environment and Civil Engineering, Jiangnan University, Wuxi, Jiangsu 214122
    4. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101
    5. Chinese Research Academy of Environmental Sciences, Beijing 100021
  • Received:2019-12-07 Accepted:2020-03-08 Online:2020-12-20 Published:2020-05-25
  • Contact: Nengwen Xiao,Jianjun Wang

Abstract:

Understanding community composition variation (beta-diversity) along environmental and spatial gradients is a central interest in ecology and conservation biology. Although bacterial elevational patterns are somewhat established, their underlying processes were understudied. To better understand the patterns behind beta diversity, we investigated aquatic bacterial community composition in individual streams in Nujiang and Lancang rivers located in the Hengduan Mountains of the Tibetan Plateau. Using Baselga’s approach of beta diversity partitioning based on the Sørensen dissimilarity index, we explored the elevational patterns of turnover and nestedness through linear models and measured the relative importance of environmental, climatic, and spatial factors on bacterial beta diversity with multiple regression on distance matrices and variation partitioning analyses. Our results showed bacterial community composition differed between the Lancang and Nujiang rivers. Total beta diversity and turnover component increased with increasing elevational distance, and total beta diversity was driven by turnover component. Climatic and environmental factors were important predictors of total beta diversity and turnover component in the two catchments, and all the significant correlations were positive. The highest correlation factors were elevation distance (R 2 = 0.408, P < 0.001) and mean annual temperature (R 2 = 0.417, P < 0.001). The variation partitioning results suggest nestedness component was heavily affected by dispersal limitation while total beta diversity and turnover were mainly affected by environmental filtering. Moreover, harsher climate conditions will increase total beta diversity and turnover, and form stronger environmental filtering processes that impact the bacterial species composition. Our research shows that the conservation of bacterial diversity in the stream of Hengduan Mountains in Tibet needs to target the whole multiple sites, rather than a few richest sites of biodiversity.

Key words: beta diversity, turnover, nestedness, elevation gradient, climate, environmental filtering