Abstract:

Aims: Protozoa are important components of soil microbial communities, playing dual roles as decomposers and reducers in ecosystems. They are instrumental in maintaining ecosystem balance, health, and acting as hubs for energy flow. Vegetation type is an important ecological factor affecting the characteristics of soil microbial communities, and the diversity of microbial communities also varies under different vegetation types. Most of the studies have focused on soil bacterial and fungal communities, and there are relatively few studies on the assembly mechanisms of protozoan community under different vegetation types. Meanwhile, the trade-offs in the community assembly processes closely relate to biological attributes and habitat conditions. It is of great significance for exploring the characteristics and construction processes of soil protozoan communities under different vegetation types, which could strengthen understanding the assembly mechanisms of protozoan community diversity in various ecosystems and strengthening biodiversity conservation.

Method: This study used high-throughput sequencing techniques to explore the diversity of soil protozoan communities under forest, shrub and grassland in the Luya Mountain. We aimed to reveal the soil protozoa community assembly mechanisms.

Results: The results showed that soil protozoan communities encompassed 9 kingdoms, 23 phyla, 58 classes, 117 orders, 215 families, 335 genera, and 1,979 operational taxonomic units in the Luya Mountain. There were no significant differences in alpha diversity of soil protozoan communities among forest, grassland, and shrub in Luya Mountain. The structures of protozoan communities exhibited variations across different vegetation types. Redundancy analysis results showed that soil total phosphorus and water content were the key environmental factors in determining the structures of protozoan communities in different vegetation types. The results of null model analysis showed that the assembly processes of soil protozoan communities in different vegetation types of Luya Mountain were primarily governed by random processes. Molecular ecological network analysis showed that the complexities of soil protozoan communities decreased from grassland to shrub and forest.

Conclusion: This study revealed key ecological factors affecting the species compositions and diversities of soil protozoan communities in forest, grassland and shrub of Luya Mountain. These results preliminarily clarified the complexities and assembly mechanisms of soil protozoan communities under different vegetation types, and provided theoretical basis and data support for further understanding the interrelationships and assembly mechanisms of soil biological communities at various trophic levels.

Key words: Protozoa, community diversity, plant type, community assembly