Microorganisms are essential to grassland soil ecosystems and critical in biogeochemical cycles. Microbial communities can be classified into different ecological groups according to common life-history traits, which greatly benefits the understanding of processes in highly heterogeneous microbial communities. Yet, the understanding of climate-dependent life history strategies and driving mechanisms of microbial community assembly in riparian grasslands is very limited.

Researchers from Wuhan Botanical Garden investigated the differences in the life history strategies of abundant and rare bacteria in the Qinghai-Tibet Plateau riparian grassland soils under distinct climate conditions and their impact on the composition, assembly processes and functionality of the microbial communities.

The results showed that the abundant bacteria of the Qinghai-Tibet Plateau grassland soils in the Lhasa and Nyang watersheds exhibited distinct life history strategies due to pronounced differences in climate. The abundant bacteria in the humid and warm climate of the Nyang River watershed were more characterized by r strategy (Proteobacteria-dominated), while the abundant bacteria in the arid and harsh climate of the Lhasa River were more characterized by K strategy (Acidobacteria-dominated). Different life history strategies of these bacterial communities resulted in distinct community compositions, assembly processes, coexistence patterns, and ecological roles of soil bactereia in the two differing riparian grasslands.

The community assembly and niche width results suggested that the bacteria community in the Lhasa region were more susceptible to environmental selection than those in the Nyang region. Moreover, the competition potential within bacterial communities was higher, and abundant bacteria had stronger cooperation potential and greater metabolic capacity in the Lhasa region than those in the Nyang region.

It is the first study to investigate the life history strategies of abundant vs. rare bacteria. It reveals that differences in life history strategies of abundant bacteria are much more significant than of rare bacteria.

This research enlightens the life history strategies of bacteria with different abundances in the context of global climate change and how they maintain biogeochemical cycles in riparian grassland ecosystems.

This work was supported by the Starting Research Fund and Opening Research Fund from the Key Laboratory of Aquatic Botany and Watershed Ecology, Chinese Academy of Sciences. The relevant results have been published in Science of the Total Environment entitled “The unique climate shapes distinct life-history traits of abundant bacteria in Tibetan plateau grassland soil”.