Body size determines soil community assembly in a tropical forest

Area of Science:

• Ecology
• Soil Science
• Biodiversity Studies

Background:

• Tropical forests host immense biodiversity, but the drivers of soil community assembly across body sizes remain underexplored.
• Understanding the balance between environmental selection and neutral processes is key to explaining biodiversity patterns.

Purpose of the Study:

• To investigate the influence of neutral processes versus environmental selection on tropical soil biota assembly across a wide range of body sizes.
• To identify key environmental drivers and the role of body size in shaping soil community structure.

Main Methods:

• Conducted a comprehensive census of soil biota in a 12-hectare tropical forest plot using DNA metabarcoding.
• Analyzed 19 taxonomic groups, from microbes to mesofauna, to assess community composition and distribution patterns.

Main Results:

• Soil community assembly across 19 taxonomic groups was predominantly stochastic, indicating the prominence of neutral processes.
• Weak but significant influences of aluminum, topography, and plant species on bacterial, protist, and fungal communities were identified.
• Body size correlated with assembly processes; soil mesofauna exhibited more stochastic assembly than microbial communities.

Conclusions:

• Neutral processes play a dominant role in tropical soil community assembly at this scale.
• Body size is a critical factor determining the relative importance of neutral processes and environmental selection in soil ecosystems.
• Future spatial models of tropical soil food webs must incorporate body size to accurately reflect community assembly rules.