# Fungal Community Assembly in Standing Deadwood: Stochastic vs. Deterministic Processes Across Decay Stages*

## TL;DR

This study explores how fungal communities change in deadwood over time, finding that randomness plays a bigger role in later decay stages.

## Contribution

The study introduces a model linking key fungal biomarkers to decay stages and highlights the role of wood chemistry in community assembly.

## Key findings

- Fungal diversity increases up to decay class III and then declines.
- Stochastic processes dominate fungal assembly in later decay stages.
- Chemical properties of deadwood strongly influence fungal community structure.

## Abstract

A growing body of evidence suggests that fungi play an essential role in the decomposition process of deadwood. However, the dynamic pattern of fungal community assembly in deadwood remains poorly understood. Here, we employed a ‘space‐for‐time’ substitution approach in the local forest to track shifts in the deadwood mycobiota during decay. The results indicated that fungal community diversity increased from decay classes I to III, then decreased from decay classes III to IV. A high degree of structural similarity in fungal communities could occur between decay classes I and II, or decay classes III and IV. Fungal community assembly in decay classes III and IV was more governed by stochastic processes than in decay classes I and II. Moreover, we identified the six most important biomarkers and established a model that associates these biomarkers with decay classes using a random forest analysis. The chemical properties of deadwood substrates were determined to be the important driver of fungal community assembly and diversity. Our work provides novel insights into changes and the generation of fungal communities within deadwood.

Pinus massoniana
, a key conifer in southern China, often succumbs to pests and strong winds, leaving abundant standing deadwood. However, under local field conditions, the mechanism of fungal community assembly within this deadwood remains poorly investigated. This study reveals the dynamics and drivers of these communities within
Pinus massoniana
deadwood during decomposition.