Soil microbes drive the classic plant diversity-productivity pattern

Area of Science:

• Ecology
• Microbiology
• Plant Science

Background:

• Ecosystem productivity often increases with plant species diversity, a pattern previously attributed to niche complementarity and resource partitioning.
• Understanding the mechanisms behind this diversity-productivity relationship is crucial for predicting ecosystem responses to species loss.

Purpose of the Study:

• To investigate the role of host-specific soil microbes in the plant diversity-productivity relationship in grasslands.
• To determine whether soil microbes are a primary driver of the asymptotic diversity-productivity pattern.

Main Methods:

• Utilized an analytical model and experimental approaches to study the interactions between plant diversity, soil microbes, and ecosystem productivity.
• Conducted experiments in both microbe-present and sterilized soils to compare the effects of microbial communities.
• Assessed plant disease incidence and productivity across varying levels of plant species diversity.

Main Results:

• Plant productivity increased by nearly 500% with increasing diversity in the presence of soil microbes, primarily due to reduced plant disease.
• Host-specific soil microbes exacerbated disease in low-diversity, conspecific-trained soils, while increasing diversity reduced disease and boosted productivity.
• The diversity-productivity relationship was significantly weaker in microbe-free soils, indicating a lesser role for niche complementarity.

Conclusions:

• Host-specific soil microbes are major determinants of the diversity-productivity relationship in grasslands.
• Density-dependent plant disease, mediated by soil microbes, is a primary driver of reduced productivity at low species diversity.
• Soil microbes play an integral role in ecosystem functioning and must be considered in biodiversity research.