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Updated: Jan 11, 2026
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Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter
Published on: March 12, 2013
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Keystone protist suppression triggers mesopredator release and biotic homogenization in complex soil microbial
François Maillard1, Fredrik Klinghammer1, Briana H Beatty2
1Department of Biology, Lund University, 223 62 Lund, Sweden.
The ISME Journal
|November 14, 2025
Summary
Microbial predators, even rare ones, can act as keystone species. Suppressing a specific protist predator in a soil food web altered protist diversity and fungal communities, demonstrating their significant ecological impact.
Area of Science:
- Microbial ecology
- Soil science
- Food web dynamics
Background:
- The keystone species concept explains how certain species disproportionately influence community structure.
- Experimental validation in microbial ecology is challenging due to difficulties in targeted species removal.
Purpose of the Study:
- To experimentally test the keystone species concept in a soil microbial food web.
- To investigate the effects of suppressing a specific protist predator on microbial community dynamics.
Main Methods:
- Developed a microfluidic soil chip system for microscale ultraviolet-induced phototoxicity.
- Targeted a hypotrich ciliate (subclass Hypotrichia) for selective suppression.
- Utilized microscopy and high-throughput amplicon sequencing to analyze microbial communities across trophic levels.
Main Results:
- Protist diversity increased, and community composition converged (biotic homogenization) after predator suppression.
- Bacterial communities showed no significant changes in abundance, richness, or composition.
- Fungal diversity decreased due to altered protist predation patterns.
Conclusions:
- Low-abundance microbial predators can function as keystone species.
- Predator suppression caused cascading effects on protist and fungal communities.
- This study provides direct experimental evidence for the keystone species concept in microbial brown food webs.
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