Plant Functional Traits Define Microbial Response to Nutrient Availability in Tropical Rainforest Soil

Area of Science:

• Ecology
• Soil Science
• Biogeochemistry

Background:

• Global nutrient inputs are imbalanced, with high nitrogen (N) and low phosphorus (P) potentially altering plant traits and soil microbial communities.
• Understanding how these nutrient imbalances affect plant-microbe interactions and soil functions in tropical rainforests is crucial but remains underexplored.

Purpose of the Study:

• To investigate nutrient-induced shifts in plant functional traits and soil microbial communities in phosphorus-limited tropical rainforests.
• To examine the relationship between plant traits and microbial composition under varying soil N and P levels.
• To determine how vegetation regulates microbial responses to nutrient enrichment.

Main Methods:

• Spatial multivariate analyses across 160 km² of tropical rainforest.
• A 14-year in situ nutrient addition experiment.
• Characterization of plant functional traits and soil microbial community composition.

Main Results:

• Elevated soil N increased P limitation, leading to conservative plant economics (higher leaf N:P ratios, dry matter content).
• This shift correlated with increased abundance of bacterial r-strategists and arbuscular mycorrhizal/saprotrophic fungi.
• P addition promoted plant acquisition economics (higher leaf P, specific leaf area) and increased bacterial K-strategists and ectomycorrhizal fungi.

Conclusions:

• Vegetation traits selectively influence soil microbiomes for efficient P acquisition in P-limited tropical soils.
• These plant-microbe interactions can accelerate nutrient cycling and impact soil carbon sequestration.
• Models predicting microbial dynamics under changing nutrient conditions should incorporate plant traits.