TY - JOUR

T1 - Tree diversity effects on litter decomposition are mediated by litterfall and microbial processes

AU - Beugnon, Rémy

AU - Eisenhauer, Nico

AU - Bruelheide, Helge

AU - Davrinche, Andréa

AU - Du, Jianqing

AU - Haider, Sylvia

AU - Hähn, Georg

AU - Saadani, Mariem

AU - Singavarapu, Bala

AU - Sünnemann, Marie

AU - Thouvenot, Lise

AU - Wang, Yanfen

AU - Wubet, Tesfaye

AU - Xue, Kai

AU - Cesarz, Simone

N1 - Funding Information: – This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation – 319936945/GRK2324 and Ei 862/18‐1), the University of Chinese Academy of Sciences (UCAS), and CAS Strategic Priority Research Programme (XDA20050104). We gratefully acknowledge the support by the German Centre for Integrative Biodiversity Research (iDiv) funded by the German Research Foundation (DFG– FZT 118, 202548816). Publisher Copyright: © 2023 The Authors. Oikos published by John Wiley & Sons Ltd on behalf of Nordic Society Oikos.

PY - 2023/10

Y1 - 2023/10

N2 - Forest ecosystems are critical for their carbon sequestration potential. Increasing tree diversity has been shown to enhance both forest productivity and litter decomposition. Litter diversity increases litter decomposability by increasing the diversity of substrates offered to decomposers. However, the relative importance of litter decomposability and decomposer community in mediating tree diversity effects on decomposition remains unknown. Moreover, tree diversity modulation of litterfall spatial distribution, and consequently litter decomposition, has rarely been tested. We studied tree diversity effects on leaf litter decomposition and its mediation by the amount of litterfall, litter species richness and decomposability, and soil microorganisms in a large-scale tree diversity experiment in subtropical China. Furthermore, we examined how litter functional identity and diversity affect leaf litter decomposability. Finally, we tested how leaf functional traits, tree biomass, and forest spatial structure drive the litterfall spatial distribution. We found evidence that tree species richness increased litter decomposition by increasing litter species richness and the amount of litterfall. We showed that soil microorganisms in this subtropical forest perform 84–87% of litter decomposition. Moreover, changes in the amount of litterfall and microbial decomposition explained 19–37% of the decomposition variance. Additionally, up to 20% of the microbial decomposition variance was explained by litter decomposability, while litter decomposability itself was determined by litter functional identity, diversity, and species richness. Tree species richness increased litter species richness and the amount of litterfall (+200% from monoculture to eight-species neighborhood). We further demonstrated that the amount of species-specific litterfall increased with increasing tree proximity and biomass, and was modulated by leaf functional traits. These litterfall drivers increased the spatial heterogeneity of litter distribution, and thus litter decomposition. We highlighted multiple biomass- and diversity-mediated effects of tree diversity on ecosystem properties driving forest nutrient cycling. We conclude that considering spatial variability in biotic properties will improve our mechanistic understanding of ecosystem functioning.

AB - Forest ecosystems are critical for their carbon sequestration potential. Increasing tree diversity has been shown to enhance both forest productivity and litter decomposition. Litter diversity increases litter decomposability by increasing the diversity of substrates offered to decomposers. However, the relative importance of litter decomposability and decomposer community in mediating tree diversity effects on decomposition remains unknown. Moreover, tree diversity modulation of litterfall spatial distribution, and consequently litter decomposition, has rarely been tested. We studied tree diversity effects on leaf litter decomposition and its mediation by the amount of litterfall, litter species richness and decomposability, and soil microorganisms in a large-scale tree diversity experiment in subtropical China. Furthermore, we examined how litter functional identity and diversity affect leaf litter decomposability. Finally, we tested how leaf functional traits, tree biomass, and forest spatial structure drive the litterfall spatial distribution. We found evidence that tree species richness increased litter decomposition by increasing litter species richness and the amount of litterfall. We showed that soil microorganisms in this subtropical forest perform 84–87% of litter decomposition. Moreover, changes in the amount of litterfall and microbial decomposition explained 19–37% of the decomposition variance. Additionally, up to 20% of the microbial decomposition variance was explained by litter decomposability, while litter decomposability itself was determined by litter functional identity, diversity, and species richness. Tree species richness increased litter species richness and the amount of litterfall (+200% from monoculture to eight-species neighborhood). We further demonstrated that the amount of species-specific litterfall increased with increasing tree proximity and biomass, and was modulated by leaf functional traits. These litterfall drivers increased the spatial heterogeneity of litter distribution, and thus litter decomposition. We highlighted multiple biomass- and diversity-mediated effects of tree diversity on ecosystem properties driving forest nutrient cycling. We conclude that considering spatial variability in biotic properties will improve our mechanistic understanding of ecosystem functioning.

KW - BEF China

KW - biodiversity-ecosystem functioning

KW - carbon cycle

KW - common garden experiment

KW - leaf decomposability

KW - leaf traits

KW - litterfall

KW - nitrogen cycle

KW - Biology

UR - http://www.scopus.com/inward/record.url?scp=85164472642&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/d1a361f6-8821-3524-ba58-07977604504b/

U2 - 10.1111/oik.09751

DO - 10.1111/oik.09751

M3 - Journal articles

AN - SCOPUS:85164472642

VL - 2023

JO - Oikos

JF - Oikos

SN - 0030-1299

IS - 10

M1 - e09751

ER -