Microbial Life History Mediates the Drought-Induced Decrease in Wood Decomposition in Subtropical Forests

Area of Science:

• Forest Ecology
• Biogeochemistry
• Microbial Ecology

Background:

• Wood decomposition is vital for forest carbon cycling.
• Drought impacts microbial communities and wood decomposition processes.
• Understanding microbial strategies, wood traits, and microclimate interactions under drought is crucial.

Purpose of the Study:

• To investigate how drought affects wood decomposition rates.
• To determine the roles of microbial strategies (fungal K/r-strategies) and wood traits in regulating decomposition under drought.
• To compare the drought sensitivity of fungal and bacterial communities in wood decomposition.

Main Methods:

• A throughfall exclusion experiment simulating drought (35% and 70% rainfall reduction).
• Analysis of wood decomposition rates (CO2 efflux) across 12 tree species.
• Assessment of fungal and bacterial community composition (Basidiomycota, Ascomycota) and fungal K/r-strategies.

Main Results:

• Drought significantly reduced wood CO2 efflux rates.
• Wood traits (density, carbon reduction) and fungal K/r-strategies were primary drivers of reduced decomposition.
• Higher abundance of Basidiomycota and lower Ascomycota correlated with faster decomposition.
• Fungal K/r-strategies positively correlated with wood CO2 efflux under all drought levels, while bacterial strategies did not.

Conclusions:

• Fungi exhibit greater drought sensitivity than bacteria in wood decomposition.
• Shifts in fungal communities and wood traits are key regulators of decomposition under drought.
• Findings improve predictions of forest carbon cycling and climate-biosphere feedbacks.