Size exclusion experiment in a grassland field unravels top–down control of the soil fauna on microbial community assembly

• Published in: Ecology letters Vol. 27; no. 6; pp. e14442 - n/a
• Main Authors: Jeanbille, Mathilde, Romdhane, Sana, Breuil, Marie‐Christine, Bru, David, Geisen, Stefan, Mounier, Arnaud, Spor, Aymé, Philippot, Laurent
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.06.2024
• Subjects: Animals; Assembly; Bacteria; Biota; Body Size; Eukaryota - physiology; Fungi; Fungi - physiology; Grassland; grassland soil; Grasslands; interkingdom interactions; Microbial activity; Microbiomes; Microbiota; Microorganisms; protists; size‐exclusion; Soil - chemistry; Soil fauna; Soil Microbiology; Soil microorganisms; Soils; Trophic levels; protists; size‐exclusion; bacteria; grassland soil; interkingdom interactions; fungi
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.14442

Highly diverse and abundant organisms coexist in soils. However, the contribution of biotic interactions between soil organisms to microbial community assembly remains to be explored. Here, we assess the extent to which soil fauna can shape microbial community assembly using an exclusion experiment in a grassland field to sort soil biota based on body size. After 1 year, the exclusion of larger fauna favoured phagotrophic protists, with increases up to 32% in their proportion compared to the no‐mesh treatment. In contrast, members of the bacterial community and to a lesser extent of the fungal community were negatively impacted. Shifts in bacterial but not in fungal communities were best explained by the response of the protistan community to exclusion. Our findings provide empirical evidence of top–down control on the soil microbial communities and underline the importance of integrating higher trophic levels for a better understanding of the soil microbiome assembly. We assessed the extent to which the soil fauna can shape microbial community assembly using an exclusion experiment in a grassland field to sort soil biota based on body size. Exclusion of the soil fauna according to body size led to cascading effects through the food web. In particular, exclusion of larger soil fauna positively impacted phagotrophic protists with subsequent effects on microbial community composition.