Detection of the horizontal spatial structure of soil fungal communities in a natural forest

Abstract

Soil microbes are considered to be a key determinant of the aboveground plant community. They are not distributed uniformly in the environment, and their activity, abundance, and ecosystem functioning could vary across localities, characterized by high b-diversity. Investigating factors that contribute to high b-diversity can help infer the possible mechanisms of microbial community assembly, and predict the scale and extent of impacts that soil microbes have on the plant community. Because soil systems consist of multiple horizons (i.e., vertical stratification) associated with different soil properties, complete understanding of high b-diversity requires consideration of both horizontal and vertical spatial structures of soil microbial communities. We studied the community composition of soil fungi from the O-and A-horizons in a Castanopsis-dominated temperate forest, and compared horizontal spatial autocorrelation in species composition between the two soil horizons (O-versus A-horizons). Pyrosequencing analysis yielded 67,129 sequencing reads, summed across all the 48 forest soil samples. Clustering analysis resulted in 597 molecular operational taxonomic units (OTUs), 68 % of which were identified as fungi, represented by four phyla. The Mantel test revealed that the O-horizon communities are spatially clustered, and the observed high b-diversity was driven not only by changes in OTUs present, but also by high turnover in identities of OTUs in soil samples. Furthermore, Mantel correlogram analysis showed that the O-horizon communities resembled each other in composition within the range of 50 m, whereas the A-horizon communities lacked such horizontal autocorrelation. These differences in the scale patchiness could arise from two processes: (1) that environmental conditions could show higher heterogeneity in finer scale at the A-horizon than at the O-horizon; and/or (2) dispersal could be more frequent at the O-horizon than the A-horizon. The present study suggests that either environmental filtering (i.e., the niche-based process) or dispersal limitation (i.e., neutral process) could characterize the observed patterns of spatial clustering in the soil fungal community.

Host plant phylogeny and abundance predict root‐associated fungal community composition and diversity of mutualists and pathogens

“…Spatial distance explained a small, but statistically significant component of variance in RAF community composition after accounting for phylogenetic distance among hosts. The fine‐scale spatial structure we observed in RAF community composition corroborates similar findings for Neotropical soil fungi (Peay et al, ), subtropical RAF (Toju, Sato, & Tanabe, ), temperate RAF (Kadowaki et al, ), and temperate soil fungi (Bahram et al, ). The presence of spatial structure could indicate dispersal limitation (Peay et al, ).…”

Distribution patterns of plant communities and their associations with environmental soil factors on the eastern shore of Lake Taihu, China

“…Quantifying the variation in species diversity and community composition with location provided the opportunity to infer possible mechanisms of vegetation community assembly (Kadowaki et al 2014;Reid, Reid, and Thoms 2016;Yamaji et al 2016). Similar results were found in lowlands, temperate forests, arid grasslands, beech forests, and natural forest (Peres-Neto et al 2006;Dwirek, Kauffman, and Baham 2006).…”

Distribution patterns of microbial communities in ultramafic landscape: a metagenetic approach highlights the strong relationships between diversity and environmental traits

“…() in alpine systems and by Kadowaki et al . () in mixed Japanese forests. Thus, all these elements could explain the combined effect of edaphic variables and plant community composition on the bacterial and fungal community variation.…”