Negative effects of canopy gaps on soil physicochemical properties and microbial community structure and functions in Picea Schrenkiana pure forests

Aims

Canopy gaps, as small-scale disturbances in forest ecosystems, are critical for maintaining soil nutrient cycling and microbial communities. Picea schrenkiana forests are important ecological barriers and valuable biological resources in the Tianshan Mountains, investigating the effects of gaps disturbances on their ecosystems has great theoretical and practical significance. We aimed at determining the effects of canopy gaps disturbance on soil physicochemical properties and structure and function of microbial communities.

Methods

Non-gaps (NG) as a control, employed high-throughput sequencing technology, combined with R software, hierarchical partitioning analysis, redundancy analysis, and correlation analysis. Investigated soil physicochemical properties, microbial community composition, diversity, structure, and function, and their influencing factors in small gaps (GS), medium gaps (GM), and large gaps (GL).

Results

Compared to NG, soil physicochemical properties, and bacterial and fungal community diversity significantly decreased from GS to GL, but pH and dominant phyla abundance exhibited fluctuating. Functional groups abundance increased in GS and decreased in GM and GL. Topological attributes were higher in bacterial networks than fungal networks, with both dominant and rare taxa coexisting as modules, but network interactions were reduced. Additionally, changes in soil carbon, nitrogen, phosphorus, pH, soil water content, and soil carbon and nitrogen significantly affected the composition, diversity, structure, and function of bacterial and fungal communities, respectively.

Conclusions

Our results suggest that the negative effects of canopy gap disturbances on soil physicochemical properties drive structural and functional changes in microbial communities. This study provides important information for the conservation and management of Picea schrenkiana forest ecosystems.