Scale-dependent effects of climate and geographic distance on bacterial diversity patterns across northern China's grasslands

Abstract

Patterns of variation in plant and animal diversity along precipitation gradients have been extensively studied, but much less is known about how and to what extent precipitation affects the biogeographic distribution of microbial diversity in arid areas across large spatial scales. Here we collected soils from 54 sites along a 3700 km transect covering a wide range of grassland ecosystems with distinct aridity gradients. We quantified the bacterial community diversity and the effects of climate, edaphic parameter and geographic distance on the bacterial community structure using high-throughput 16S rRNA gene sequencing. Of the 35 phyla detected, 6 were dominant: Actinobacteria, Acidobacteria, Alphaproteobacteria, Deltaproteobacteria, Bacteroidetes and Planctomycetes. Aridity was a major factor influencing bacterial diversity, community composition and taxon abundance. Although the pattern of bacterial species richness is markedly different from that of plant species richness, most soil bacteria were endemic to particular bioregions like macro-organisms. Community similarity significantly declined with environmental distance and geographic distance (r = -0.579 and -0.773, respectively). Geographic distance (historical contingencies) contributed more to bacterial community variation (36.02%) than combined environmental factors (24.06%). Overall, our results showed that geographic distance and climatic factors concurrently govern bacterial biogeographic patterns in arid and semi-arid grassland.

Differentiations of determinants for the community compositions of bacteria, fungi, and nitrogen fixers in various steppes

“…Firstly, most of bacterial species were homogeneously shared by the desert, typical, and meadow steppes and the unique species in specific steppe were very few. Although it has been reported that soil characteristics were important factors in shaping soil bacterial communities (Griffiths et al, 2011;Lauber et al, 2009), climate conditions and plantation could also cause some shifts of bacterial communities (Leff et al, 2018;Wang et al, 2015), interestingly, these factors did not show clear influence on the bacterial compositions in the steppes in the current work. The question is which factor would be more important in relation to the distributions of bacterial compositions between the steppes.…”

“…The geographic locations of the steppes follow the order of meadow, typical, and desert steppes from the east to the west of Inner Mongolia. This would imply a possible interpretation, the desert and typical steppes, and typical and meadow steppes were adjacent; they possessed high bi‐shared microbial communities (Wang et al, ). Furthermore, few bi‐shared microbial communities that detected between these two ecosystems might also be linked to the transitions of a few grass species and climate conditions between them (Yan et al, ).…”

Soil organic matter availability and climate drive latitudinal patterns in bacterial diversity from tropical to cold temperate forests

“…Whether the processes and factors that control the spatial patterns of macro-organisms, such as contemporary environmental conditions and historical contingencies, also apply to micro-organisms remains unclear (Ge et al, 2008;Martiny et al, 2006;Ramette & Tiedje, 2007). Recent studies have documented a wide range of biotic and abiotic factors that influence microbial diversity and community structure such as soil pH (Chu et al, 2010;Fierer & Jackson, 2006;Lauber, Hamady, Knight, & Fierer, 2009), vegetation (Peay, Baraloto, & Fine, 2013), temperature , and aridity (Wang et al, 2015). However, as noted by Ge et al (2008) and de Vries et al (2012), most studies have documented the variation and potential patterns of microbial diversity under certain ecological variation or gradient.…”

Fungal community reveals less dispersal limitation and potentially more connected network than that of bacteria in bamboo forest soils

“…According to Vellend's conceptual synthesis of community ecology (Vellend, ), dispersal refers to the movement of organisms across space; selection represents the changes in community structure caused by deterministic fitness differences between taxa; drift reflects stochastic changes in the relative abundances of different taxa; diversification produces new genetic variation. There is increasing awareness that all of these processes operate in combination to assemble the community; however, their relative importance varies across different spatial scales (Martiny, Eisen, Penn, Allisona, & Horner‐Devine, ; Wang et al., ) and habitat types (Wang et al., , ). Recently, evidence has shown that the relative importance of the individual drivers of microbial community assembly also varies between different taxa (Brown & Jumpponen, ).…”