5. Conclusions
In summary, the present study systematically investigated the
biogeographic patterns, environmental adaptations, assembly processes,
and co-occurrence patterns of abundant and rare bacteria in the
sediments of the Yarlung Tsangpo River. The present work linked abundant
and rare bacterial community traits, including phylogenetic clustering,
environmental thresholds, and phylogenetic signals of ecological
preferences to different environmental conditions, and revealed the
factors mediating community assembly processes. We found that abundant
taxa had stronger environmental adaptation and exhibited ubiquitous
distribution, whereas rare taxa were more sensitive to environmental
changes and exhibited restricted distribution. Forest area and TN were
the major factors mediating the balance of stochastic and deterministic
assembly processes in the abundant and rare subcommunities,
respectively. Although the rare taxa were less connected and located
more peripherally within the co-occurrence network compared with
abundant taxa, both played important roles in maintaining network
stability. These results expand our understanding of the mechanisms
underlying the maintenance of microbial diversity and predicting
microbial responses to environmental perturbation caused by climate
change and human activities in the Yarlung Tsangpo River.