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Scale-dependent diversity-biomass relationships can be driven by tree mycorrhizal association and soil fertility

Cite this dataset

Mao, Zikun et al. (2023). Scale-dependent diversity-biomass relationships can be driven by tree mycorrhizal association and soil fertility [Dataset]. Dryad.


Diversity–biomass relationships (DBRs) often vary with spatial scale in terrestrial ecosystems, but the mechanisms driving these scale-dependent patterns remain unclear, especially for highly heterogeneous forest ecosystems. This study explores how mutualistic associations between trees and different mycorrhizal fungi (i.e., arbuscular mycorrhizal (AM) vs. ectomycorrhizal (EM) association) modulate scale-dependent DBRs. We hypothesized that in soil-heterogeneous forests with a mixture of AM and EM tree species, (i) AM and EM tree species respond in contrasting ways (i.e., positively vs. negatively respectively) to increasing soil fertility, (ii) AM tree dominance contributes to higher tree diversity and EM tree dominance contributes to greater standing biomass and that as a result, (iii) mycorrhizal associations exert an overall negative effect on DBRs across spatial scales. To empirically test these hypotheses, we collected detailed tree distribution and soil information (nitrogen, phosphorus, organic matter, pH, etc.) from seven temperate and subtropical AM-EM mixed forest mega-plots (16–50 ha). Using spatial codispersion null model and structural equation modeling, we identified the relationships among AM or EM tree dominance, soil fertility, tree species diversity and biomass, and thus DBRs across 0.01–1 ha scales. We found first evidence overall supporting the above three hypotheses in these AM-EM mixed forests: (i) In most forests, with increasing soil fertility tree communities changed from EM-dominated to AM-dominated. (ii) Increasing AM tree dominance had an overall positive effect on tree diversity and a negative effect on biomass, even after controlling for soil fertility and number of trees. Together, (iii) the changes in mycorrhizal dominance along soil fertility gradients weakened the positive DBR observed at 0.01–0.04 ha scales in nearly all forests and drove negative DBRs at 0.25–1 ha scales in four out of seven forests. Hence, this study highlights a soil-related mycorrhizal dominance mechanism that could partly explain why in many natural forests, biodiversity-ecosystem functioning (BEF) relationships shift from positive to negative with increasing spatial scale.


See the "Materials and Methods" section in the manuscript for details.


National Natural Science Foundation of China, Award: Grant 31961133027

Chinese Academy of Sciences, Award: Grant ZDBS-LY-DQC019

University of Hong Kong

China Postdoctoral Science Foundation, Award: 2021M703397

Special Research Assistant Project of Chinese Academy of Sciences, Award: 2022000056

Institute of Applied Ecology, Award: IAEMP202201

National Natural Science Foundation of China, Award: 31925027

Smithsonian Institution

National Science Foundation

National Zoological Park

HSBC Climate Partnership

International Center for Advanced Renewable Energy and Sustainability (I-CARES) at Washington University in St. Louis

Tyson Research Center

Ministry of Science and Technology of the People's Republic of China, Award: 2022YFF1300501