Host Filtering Shapes the Soil-gut Microbiome Linkages in Pastoral Systems

Area of Science:

• Microbial ecology
• Ruminant microbiome research
• Pasture management systems

Background:

• Soil and ruminant gut microbiomes are interconnected in grazing systems.
• The influence of pasture management on soil-gut microbial connections is not well understood.

Purpose of the Study:

• Characterize bacterial communities in soil and ruminant feces.
• Identify shared taxa and evaluate soil-gut diversity relationships.
• Determine the impact of pasture management on soil-gut microbial connectivity.

Main Methods:

• 16S rRNA gene sequencing of soil and fecal samples from cattle and sheep.
• Analysis of bacterial communities under standard vs. diverse and contemporary vs. regenerative pasture management.
• Spearman correlations and Procrustes analyses to assess dominance patterns and diversity relationships.

Main Results:

• Several bacterial taxa (e.g., Prevotella copri, Faecalibacterium prausnitzii) were shared between soil and gut, but more prevalent in the gut.
• Soil exhibited significantly higher bacterial alpha diversity than the gut across all treatments.
• Pasture diversity or management did not significantly affect soil-gut diversity differences or shared taxa contributions.
• Correlations between soil and gut alpha/beta diversity were weak and generally non-significant.

Conclusions:

• Gut microbial communities are primarily shaped by host-related factors and internal filtering.
• Soil acts as a reservoir and sink for gut-derived taxa, rather than a primary driver of gut microbial composition.
• Host-driven processes largely determine the soil-gut microbiome link, with limited direct influence from pasture diversity or management.