Soil microorganism distributions depend on habitat partitioning of topography in a temperate mountain forest.

As the main decomposers in forest ecosystems, soil microorganisms are crucial in maintaining ecosystem functions and services. Topographic factors are essential for soil formation and can influence the community structure of soil microorganisms by modifying the soil environment. However, a systematic understanding of the distribution mechanisms of soil microorganisms across different terrain habitats is still lacking. This study characterized soil bacteria and fungi in the valleys, mid-slopes, and ridges of the temperate deciduous broadleaf forest in Baiyun Mountain, Luoyang, to analyze the effect of topographic habitat on the distribution patterns of soil microbial communities. Results showed that the distribution of most soil microorganisms in different terrain habitats follows the principle of ecological specialization. The distribution patterns of soil bacteria and fungi are related to the terrain habitat, and the fungal community (60.48%) exhibits a stronger habitat specificity than the bacterial community (31.78%). Soil moisture has a greater influence on fungal communities than bacterial communities, whereas soil physical and chemical properties more significantly explain variations in bacterial community distribution. These findings indicate that topographic habitat significantly influences soil microbial community distribution, and bacteria show stronger habitat adaptability than fungi.

Importance: This study provides an in-depth examination of the impact of topographic habitat on the structural composition and spatial distribution characteristics of bacterial and fungal communities. The research focused on three distinct terrain habitats: valley, midslope, and ridge. Our results indicate that soil bacterial and fungal networks, along with major environmental factors, shape the composition and distribution of soil microbial communities across different terrain habitats. We found that fungi exhibit stronger habitat specificity than bacteria and are more likely to thrive in valleys with higher water content. Furthermore, major environmental factors significantly influence the distribution of soil microbial communities. These findings could inform the development of more effective forest soil management and conservation strategies tailored to different topographic habitats.