Tropical forest type influences community assembly processes in arbuscular mycorrhizal fungi

Abstract

Aim Plant community assembly in tropical rain forest has been shown to be largely governed by stochastic processes, but as arbuscular mycorrhizal (AM) fungi display limited host preference, they may not follow the same stochastic assembly pattern. Here, we determined the relative importance of environmental and spatial drivers responsible for the community assembly process of AM fungi in two types of tropical rain forest: semideciduous rain forest and dense ombrophilous forests. Location Atlantic rain forest in north‐eastern Brazil, South America. Taxon Arbuscular mycorrhizal fungi (Glomeromycotina). Methods We collected root samples from eight protected areas of Atlantic forest along a 700 km transect in north‐eastern Brazil. We measured the relative importance of deterministic and stochastic processes by redundancy analysis (RDA) and variation partitioning in comparison with null expectations using ad hoc generated neutral communities. Furthermore, we accessed species associations from co‐occurrence data, at different scales using a Bayesian approach of Hierarchical Modelling of Species Communities. Results Overall, the extent to which stochastic and deterministic processes affected community assembly depended on the forest type and the spatial scale. Specifically, we found that abiotic and biotic predictors of AM fungal community assemblages are related to environmental homogeneity in tropical rain forests. Main conclusions The results of the study show that dynamics in community assembly was clearly different between the two forest types, and that the difference most likely is due to differences in responses to environmental variables.

Different Responses of Arbuscular Mycorrhizal Fungal Community Compositions in the Soil and Roots to Nitrogen Deposition in a Subtropical Cunninghamia lanceolata Plantation in China

“…Stochastic processes are reported to dominantly drive plant community assemblies in tropical forests [64], but community assemblies of AM fungi were not always separately governed by stochasticity in natural or disturbed ecosystems [65]. Our results showed that stochasticity was a primary driver of community assemblies of AM fungi in soil and roots.…”

“…Such an alteration in ecological processes governing AM fungi could be explained by environmental conditions and/or biotic interactions [66]. For example, Pereira et al [65] provided evidence that stochasticity strongly drives AM fungal community assembly in tropical forests and found that environmental factors and species-species interactions exerted deterministic selection on AM fungi. Nitrogen enrichment may result in environmental selection in AM fungal communities and thus enhance the relative importance of determinism.…”

Host plant richness and environment in tropical forest transformation systems shape arbuscular mycorrhizal fungal richness

“…Clearly, further studies are required to cover AMF richness in the hyperdiverse tropical rain forests. Nevertheless, we identified typical taxonomic structures of the AMF communities with the highest abundance of species in the genus Glomus and lower abundances of other fungal genera or families ( Lovelock and Ewel, 2005 ; Davison et al., 2015 ; Vasar et al., 2017 ; Maciel Rabelo Pereira et al., 2020 ). Our plantation roots exhibited one unique AMF species (OTU25, Glomus sp.).…”

Local Community Assembly Mechanisms and the Size of Species Pool Jointly Explain the Beta Diversity of Soil Fungi

“…Deterministic processes refer to the biological and environmental selection mechanisms that influence communities, while stochastic processes emphasize dispersal and ecological drift [ 48 – 50 ]. Previous studies have explored the mechanisms underlying community assembly of individual soil functional groups of fungi in specific ecosystems [ 51 – 53 ]. For example, Wang et al studied EcM fungal communities of five common pine plant species in Inner Mongolia, China, and the results showed that both deterministic and stochastic processes jointly drove the community association of EcM fungi, but the stochastic process was dominant [ 52 ].…”