Similar community assembly mechanisms underlie similar biogeography of rare and abundant bacteria in lakes on Yungui Plateau, China

Abstract

The revolution of molecular techniques in the field of microbial ecology not only allows an in-depth exploration of abundant bacteria, but also confirms the existence of “rare biosphere.” However, the mechanisms underlying the assembly process of abundant and rare bacteria in plateau lakes are still poorly understood. In the present study, distribution of abundant and rare bacteria in 21 lakes on Yungui Plateau, China and the relative importance of deterministic and neutral factors to their biogeographic patterns were examined. Results surprisingly showed that similar biogeographic patterns of rare and abundant taxa were generally shaped via similar assembly mechanisms. For both bacterial groups, deterministic process strongly influenced the distribution, while neutral process was not at play. In addition, they both exhibited a weak distance–decay relationship. Nevertheless, environmental drivers of rare and abundant taxa and their importance were not exactly the same. Water physicochemical property was the most dominant driver shaping the biogeographic pattern of rare taxa, followed by lake morphology and watershed land-use, while for abundant taxa, watershed land-use was the most dominant driver and lake morphology did not play a significant role. This study suggested that rare bacteria in high-altitude aquatic ecosystems might experience equally low extinction risk and respond to environmental changes in a similar manner to abundant ones, but their ecological niches and functions were not identical. To fully understand the assembly mechanism of bacterial community, it is necessary to differentiate the community by traits of taxa.