Niche Conservatism and Community Assembly Reveal Microbial Community Divergent Succession Between Litter and Topsoil

Area of Science:

• Ecology
• Microbiology
• Environmental Science

Background:

• Understanding microbial community assembly is crucial for ecosystem restoration.
• Successional patterns and mechanisms in aboveground (litter) and belowground (topsoil) microbial communities are poorly understood.
• The niche conservatism framework offers insights into microbial community dynamics.

Purpose of the Study:

• To investigate niche partitioning, successional patterns, and community assembly of microbial communities in litter and topsoil layers.
• To apply the niche conservatism framework to long-term vegetation restoration in southwestern China.
• To differentiate assembly processes between bacterial, archaeal, and fungal communities in distinct soil horizons.

Main Methods:

• Application of the niche conservatism framework.
• Analysis of microbial community composition in litter and topsoil layers during vegetation succession.
• Quantification of niche differentiation, dispersal rates, and community assembly processes (deterministic vs. stochastic).

Main Results:

• Microbial source communities in litter shifted from topsoil-dominated to litter-dominated during succession.
• Fungal communities exhibited higher immigration rates than bacteria and archaea.
• Bacterial and fungal communities showed divergent succession (niche differentiation), while archaeal communities showed convergent succession (niche overlap).
• Litter layers had lower dispersal and turnover rates, with stronger deterministic assembly, especially for fungi.

Conclusions:

• Habitat specialization in litter layers imposes significant filtering effects on microbial colonization.
• Strategy differentiation plays a key role in shaping microbial communities during ecosystem restoration.
• Distinct assembly mechanisms govern microbial communities in litter versus topsoil environments.