Soil Microbial Functions Indicate Persistent Agricultural Legacies and Potential Alternative States Following...

Area of Science:

• Soil ecology
• Microbial ecology
• Restoration ecology

Background:

• Soil microbiomes are key indicators of ecosystem health and restoration success.
• Taxonomic assessments alone are insufficient for gauging ecological recovery due to microbial functional redundancy.
• Understanding microbial functional potential is crucial for effective land management.

Purpose of the Study:

• To investigate the recovery of soil microbial functional potential in post-agricultural restoration sites.
• To compare microbial taxonomic and functional gene diversity across different land conditions.
• To assess the influence of agricultural legacies on soil microbial functions.

Main Methods:

• Shotgun metagenomics was employed on soil samples from six restoration sites in Western Australia.
• Microbial taxonomic and functional gene diversity and composition were analyzed.
• Data were compared across degraded, passively regenerated, revegetated, and remnant land conditions.

Main Results:

• Microbial functional diversity (alpha diversity) did not significantly differ across land conditions.
• Functional composition (beta diversity) varied between remnant and revegetated sites, linked to soil abiotic factors like phosphorus.
• Remnant soils showed greater phosphorus metabolism diversity, suggesting adaptation to nutrient-limited conditions.

Conclusions:

• Soil microbial functional potential may not fully recover post-restoration due to persistent agricultural legacies.
• Altered soil properties, particularly phosphorus, can drive soil microbiomes toward alternative stable states.
• Targeted interventions, such as soil inoculations or addressing abiotic legacies, may be necessary to restore soil microbial functions and ecosystem health.