Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi and their associated trees employ contrasting nutrient acquisition strategies, strongly impacting soil carbon cycling. However, little is known about how these impacts vary with topography in subtropical forests characterized by complex terrain where both AM and EcM trees co-occur. Here, we analyzed 972 soil samples from a 25-ha fully mapped subtropical forest plot to investigate the effects of mycorrhizal type and topography on soil carbon accumulation. Results reveal that the upper slope position harbors a higher abundance of EcM tree species. Both upper slope position and EcM tree dominance (percentage of the total basal area of ECM trees vs. all trees) positively affected aboveground biomass, forest floor thickness, and soil acidification, leading to higher soil carbon concentration and C:N ratio. Slope degree had minimal effect on AM/EcM tree distribution, but could strongly regulate the effects of tree mycorrhizal type on soil carbon concentration. The positive relationship between EcM tree dominance and soil carbon concentration was observed only on gentle slopes, but was negligible on steep slopes. Therefore, soil carbon accumulation in this subtropical forest are shaped by the combined effects of topography and tree mycorrhizal types. Our findings emphasize the importance of topography in regulating AM/EcM tree distribution and their impacts on soil carbon processes. Topographic attributes should be accounted for in future studies on mycorrhizal control over soil carbon and nutrient cycling.
Copyright 2002 - 2023 Wuhan Botanical Garden,Chinese Academy Of
Sciences
Email: wbgoffice@wbgcas.cn ICP: 05004779-1
