Biodiversity and multifunctionality in a microbial community: a novel theoretical approach to quantify functional...

Area of Science:

• Ecology
• Microbiology
• Bioinformatics

Background:

• Ecosystems exhibit limited multifunctional redundancy, meaning they struggle to maintain multiple functions as biodiversity declines.
• Understanding microbial community multifunctionality is crucial for predicting ecosystem stability and function.

Purpose of the Study:

• To develop a novel theoretical approach for evaluating multifunctional redundancy in microbial communities.
• To define and validate orthologue richness as an index of community multifunctionality (MF).
• To quantify the relationship between species richness (SR) and MF and estimate biodiversity loss thresholds.

Main Methods:

• Utilized the Microbial Genome Database (MBGD) for comparative genomic analysis.
• Defined orthologue richness as a proxy for functional conservatism and community multifunctionality.
• Constructed MF vs. SR power functions (MF = cSR^a) and interpreted the exponent 'a' as a measure of multifunctional redundancy.
• Validated the orthologue richness index using microcosm experiments and simulated community assemblages.

Main Results:

• Confirmed that orthologue richness accurately predicts multiple ecosystem functions in microbial communities.
• Determined the exponent 'a' for microbial communities to range from 0.55 to 0.75.
• Quantified that a 6.6-8.9% loss in species richness can lead to a 5% reduction in multifunctionality.

Conclusions:

• Orthologue richness is a reliable index for assessing microbial community multifunctionality.
• Microbial communities exhibit a non-negligible initial loss effect of biodiversity on multifunctionality.
• The findings provide quantitative estimates for biodiversity thresholds crucial for maintaining ecosystem functions.