A comparison of microbial composition under three tree ecosystems using the stochastic process and network complexity...

Area of Science:

• Soil ecology
• Microbial ecology
• Forest science

Background:

• Environmental heterogeneity influences microbial community assembly via stochastic and deterministic processes.
• Understanding soil microbial dynamics during forest succession, particularly from coniferous to broad-leaved types, is crucial but limited.
• Soil microbes play a key role in regulating biogeochemical cycles.

Purpose of the Study:

• To investigate changes in soil bacterial and fungal diversity and community structure across temperate forest stands.
• To identify the ecological pathways driving soil microbial assembly patterns and their interactions during forest succession.
• To understand the impact of forest type (coniferous vs. broad-leaved) on soil physicochemical properties and microbial communities.

Main Methods:

• Regional-scale investigation of soil bacterial and fungal communities.
• Analysis of soil physicochemical properties, including pH, water content, total carbon, nitrogen, and phosphorus.
• Application of ecological processes (stochastic and deterministic) to analyze microbial community assembly.
• Co-occurrence network analysis to assess microbial interactions.

Main Results:

• Broad-leaved forest cover significantly increased soil pH, water content, total carbon, total nitrogen, and total phosphorus.
• Both bacterial and fungal alpha diversity indices correlated with soil physicochemical properties, particularly in broad-leaved forests.
• Coniferous forests showed a dominance of deterministic processes in community composition (bacteria: 69.4%; fungi: 88.9%), while broad-leaved forests showed a dominance of stochastic processes in bacterial communities (77.8%) and deterministic processes in fungal communities (52.8%).
• Dominant bacterial phyla included Proteobacteria, Acidobacteriota, Actinobacteriota, and Verrucomicrobiota; dominant fungal phyla included Ascomycota, Mortierellomycota, Basidiomycota, and Rozellomycota.
• Forest succession from coniferous to broad-leaved types promoted a complex soil bacterial and fungal network, with enhanced microbial interactions linked to nutrient changes.

Conclusions:

• Forest type significantly impacts soil physicochemical properties and microbial community assembly in temperate regions.
• The shift from coniferous to broad-leaved forests influences the balance of stochastic and deterministic processes governing microbial communities.
• Soil microbial communities are integral to ecosystem function, with their interactions responding dynamically to forest succession and nutrient availability.