Deterministic processes dominate soil microbial community assembly in subalpine coniferous forests on the Loess Plateau

Abstract

Microbial community assembly is influenced by a continuum (actually the trade-off) between deterministic and stochastic processes. An understanding of this ecological continuum is of great significance for drawing inferences about the effects of community assembly processes on microbial community structure and function. Here, we investigated the driving forces of soil microbial community assembly in three different environmental contexts located on subalpine coniferous forests of the Loess Plateau in Shanxi, China. The variation in null deviations and phylogenetic analysis showed that a continuum existed between deterministic and stochastic processes in shaping the microbial community structure, but deterministic processes prevailed. By integrating the results of redundancy analysis (RDA), multiple regression tree (MRT) analysis and correlation analysis, we found that soil organic carbon (SOC) was the main driver of the community structure and diversity patterns. In addition, we also found that SOC had a great influence on the community assembly processes. In conclusion, our results show that deterministic processes always dominated assembly processes in shaping bacterial community structure along the three habitat contexts.

Lake-depth related pattern of genetic and morphological diatom diversity in boreal Lake Bolshoe Toko, Eastern Siberia

“…In general, the phylogenetic diversity of sampled lake communities allows, in contrast to solely abundance-based diversity metrics, the incorporation of historical and evolutionary components of community structure [28] helping to explain current spatial patterns. We used the net relatedness index (NRI) to infer whether co-occurring sequence types within two specific diatom genera in within-lake locations differed in observed and expected mean phylogenetic diversity [30].…”

“…This signal is interpreted as environmental filtering, which arises from the adaptation of taxa to specific niche conditions. Environmental filtering has been reported for microbial communities [28,78,79], however patterns of clustering of closely-related sequence types might also result from differential dispersal or adaptive radiation events [78]. Adaptive radiation is simply defined as the divergence of closely related taxa into ecologically distinct lineages [80].…”

“…In general, genetic and morphological investigations of diatoms from water or sediment samples show a good overlap between the overall taxa composition, although genetic studies show stronger differences in the relative abundance of sequence reads per sample and indicate higher diversity as well as assigning taxa to a higher taxonomic level depending on the completeness of the reference database [22,24,27]. Besides retrieving taxonomic community compositions by metabarcoding, phylogenetically informative genetic markers also provide an estimation of the phylogenetic diversity [28], which is limited in short barcodes but can be sufficient to display phylogenetic patterns within genera [29]. In general, phylogenetic diversity analyses allow the assessment of whether communities are phylogenetically clustered, which is mostly caused by environmental filtering or if they are phylogenetically over dispersed, which can be a result of biotic interactions [30,31].…”

Experimental and computational approaches to unravel microbial community assembly

“…In the last few years, the study of community assembly in natural ecosystems has shifted its focus from a descriptive “who is there?” approach, to elucidating the relative contribution of stochastic vs. deterministic processes on community assembly (e.g. [97] , [98] , [99] ). Both approaches are indeed pertinent to increase our understanding of the particular ecosystem under investigation.…”

Short-Term Thinning Influences the Rhizosphere Fungal Community Assembly of Pinus massoniana by Altering the Understory Vegetation Diversity

“…Certainly, both deterministic processes (environmental selection) and stochastic processes (ecological drift and dispersal) influence fungal community assembly ( Li et al, 2019 ). However, at a fine scale, the limitation of fungal community assembly is mainly due to deterministic processes ( Xun et al, 2019 ; Zhao et al, 2019 ). Fungi present high abundance in soil microbial community, and they can be classified into different functional groups according to the trophic mode ( Hawksworth and Lucking, 2017 ).…”