Geologically younger ecosystems are more dependent on soil biodiversity for supporting function.

Area of Science:

• Soil ecology
• Ecosystem science
• Biogeochemistry

Background:

• Soil biodiversity provides essential metabolic functions for organic matter decomposition and nutrient cycling.
• Soil development over geological timescales may alter the reliance of ecosystem functions on biodiversity.
• Factors like plant cover, soil carbon, and microbial biomass accumulate with soil age.

Purpose of the Study:

• To investigate the relationship between soil biodiversity and ecosystem function across diverse ecosystems with varying soil ages.
• To determine how soil age influences the dependence of soil functions on soil biodiversity.
• To identify factors that mediate the biodiversity-function relationship over time.

Main Methods:

• Analysis of within-site soil biodiversity and function relationships.
• Global survey of 87 ecosystems spanning centuries to millennia of soil age.
• Statistical correlation of biodiversity-function relationships with soil age and environmental variables.

Main Results:

• A negative correlation was found between soil age and the strength of the soil biodiversity-function relationship.
• Geologically younger ecosystems show a stronger dependence of function on biodiversity compared to older ecosystems.
• Increased plant cover, soil carbon, and microbial biomass, especially in wetter conditions, reduce the critical need for biodiversity to maintain functions.

Conclusions:

• Soil biodiversity plays a more critical role in ecosystem functioning in younger, less developed soils.
• Environmental factors like plant cover and microbial biomass can compensate for reduced biodiversity's impact on function in older soils.
• The importance of soil biodiversity for ecosystem function is particularly pronounced in drier, geologically younger ecosystems with low microbial biomass.