Mycorrhizal symbioses and tree diversity in global forest communities

Unraveling the mechanisms underlying the maintenance of species diversity is a central pursuit in ecology. It has been hypothesized that ectomycorrhizal (EcM) in contrast to arbuscular mycorrhizal fungi can reduce tree species diversity in local communities, which remains to be tested at the global scale. To address this gap, we analyzed global forest inventory data and revealed that the relationship between tree species richness and EcM tree proportion varied along environmental gradients. Specifically, the relationship is more negative at low latitudes and in moist conditions but is unimodal at high latitudes and in arid conditions. The negative association of EcM tree proportion on species diversity at low latitudes and in humid conditions is likely due to more negative plant-soil microbial interactions in these regions. These findings extend our knowledge on the mechanisms shaping global patterns in plant species diversity from a belowground view.

We are deeply grateful to all members of the Global Forest Biodiversity initiative (GFBi), as well as the faculty and students at PKU, for efforts in field data collection and valuable data contributions to this study. especially, we thank to n. Picard and t. crowther for contributions in data management for GFBi. the data collection and international collaboration are facilitated by the Science-i Platform (https://science-i.org/). We thank GFBi for establishing the data standards and collaborative framework; in addition, we appreciate A. h. Gentry and the Botanical information and ecology network (Bien) for sharing the inventory data. We also acknowledge the efforts of the editors and the valuable suggestions and comments from the reviewers. this work is dedicated in memory of K.K.this study was supported by the national natural Science Foundation of china (#32125026 and #32301329) and the national Key Research development Program of china (#2022YFF0802300). the Science-i cyberinfrastructure is supported in parts by the national Science Foundation of the United States (award # 2311762) and the department of Forestry and natural Resources, Purdue University. F.J. was funded by the national natural Science Foundation of china (#32201300). J.l. was supported by grants from the Purdue University, Office of Agricultural Research and Graduate education and executive vice President for Research through their joint elevating the visibility of Research initiative. A.F.S. acknowledges that this study used GFBi plot data originally collected in Brazil with funding by conselho nacional de desenvolvimento cient\u00EDfico e tecnol\u00F3gico (cnPq) (project 520053/1998-2). We thank the team from Mexico for generating field data through the Monitoreo nacional Forestal (MOnAFOR) network with funding from the comisi\u00F3n nacional Forestal (cOnAFOR) and local projects supported by ejidos and communities. S.d.-M. benefited from a Serra-h\u00FAnter fellowship provided by the Government of catalonia (Generalitat de catalunya), and his research was supported by the project with grant number Pid2022-139558OB-i00 funded by Mcin/Aei and by \u201CeRdF A way of making europe\u201D, and by the project with grant number Pci2023-146021-2 funded by Mcin/Aei and by the european Union. J.A.-G. was funded by the natural environment Research council (neRc; ne/t011084/1) and the Oxford University John Fell Fund (10667). A.c. acknowledges the project funded under the national Recovery and Resilience Plan (nRRP), Mission 4 component 2 investment 1.4 - call for tender no. 3138 of 16 december 2021, rectified by decree n.3175 of 18 december 2021 of italian Ministry of University and Research funded by the european Union\u2013nextGenerationeU under award number: Project code cn_00000033, concession decree no. 1034 of 17 June 2022 adopted by the italian Ministry of University and Research, cUP B83c22002930006, Project title \u201Cnational Biodiversity Future centre - nBFc\u201D. We are also grateful to all the ministries and agencies from the Government of Spain, and to all the people and institutions who supported the collection, compilation, and coordination of forest inventory data, also including the Spanish national Forest inventories. J.A. and J.d. were supported by research grants 23-05272S and 25-15727S (J.A.) of the czech Science Foundation, czech-estonian Academy of Science mobility grant eAS-ee-cZ-24-2 (J.d.), and the long-term research development project no. RvO 67985939 of the czech Academy of Sciences. P.B.R. was supported by the US national Science Foundation Biological integration institutes grant nSF-dBi-2021898. c.A.J. is thankful to the State of S\u00E3o Paulo Research Foundation (FAPeSP) through the BiOtA/FAPeSP Program Grants 2003/12595-7; 2010/20811-7, 2012/51872-5 and to the Brazilian national Research council (cnPq) Peld Program grant cnPq 403710/20120). l.M. and l.K. acknowledge that plot data from central Siberian forests were collected with support from the State Assignment of the Ministry of Science and higher education of the Russian Federation [l.M. was supported by project no. FWeS-2024-0023 (state registration number 124012900558-7), and l.K. was supported by project no. FWeS-2024-0028 (state registration number 124012900557-0)]. G.v.l. acknowledges the eU, the next Generation eU Mission4 \u201Ceducation and Research,\u201D,component 2: \u201CFrom research to business\u201D investment 3.l: \u201CFund for the realization of an integrated system of research andinnovation infrastructures\u201D, Project iR0000032 italian integrated environmental Research infrastructures System (itineRiS) (cUP B53c22002150006). K.S. acknowledges Project liFe+ForBioSensing (contract number liFe13env/Pl/000048) and Poland\u2019s national Fund for environmental Protection and Water Management (contract number 485/2014/Wn10/ OPnMlF/d) and project \u201CAFteR FBS \u2013 maintenance of ForBioSensing project performance indicators,\u201D which is funded by the Forest Research institute\u2019s own research fund (no. 261509). J.A.d would like to acknowledge the Science and engineering Research Board, department of Science and technology, Govt. of india for funding (ref. no.: SRG/2022/002286) and SRM University - AP for Seed Grant (SRMAP/URG/e&PP/2022\u201323/12). h.Y.h.c. acknowledges the natural Sciences and engineering Research council of canada (RGPin-2019-05109, Rti-2017-00358, and StPGP506284) and the canadian Foundation for innovation (36014). S.K. acknowledges the Science and engineering Research Board, department of Science and technology (dSt-SeRB) for funding (ref. no.: PdF/2021/003742/lS). J.d. was supported by the czech Science Foundation (GAcR 24-11954S) and by the Ministry of education, Youth, and Sport of the czech Republic (MSMt) (#veS24, inteR-ActiOn, lUAUS24258). h.l. was funded by the national natural Science Foundation of china (31800374). Z.t. was funded by the national natural Science Foundation of china (32025025). i.d. was funded by Ministry of Science, technological development and innovation of Serbia (451-03-66/2024-03/200027). K.A.K. was funded by czech Science Foundation (23-05272S), long-term research development project of the czech Academy of Sciences (RvO 67985939), and Scientific framework of the Botanical Garden-institute FeB RAS (FWFR-2022-0008) (122040800089-2). P.B. was funded by BOF, Ghent University (Methusalem). M.Sv. was funded by czech Science Foundation (24-12210 K). J.J.c.-R. was funded by comisi\u00F3n nacional Forestal (cOnAFOR-115900). G.-J.n. was funded by heurope SUPeRB (101036849), heurope Monifun (101134991), europe Wildcard (101081177), and dutch Mnistry Agriculture, Food Security, Fisheries and nature. c.A.S. acknowledges the nASA\u2019s grants (iceSat-2, 80nSSc23K0941), carbon Monitoring System (cMS, grant 80nSSc23K1257), and commercial Smallsat data Scientific Analysis (cSdSA, grant 80nSSc24K0055). M.Ba. acknowledges the BOS Foundation, the indonesian institute of Sciences (liPi), the direktorat Fasilitasi Organisasi Politik dan Kemasyarakatan, departamen dalam negri, and the BKSdA Palangkaraya for permission to work in the MAWAS region of indonesia. She was supported by the American Society of Primatologists, the duke University Graduate School, the l.S.B. leakey Foundation, the national Science Foundation (grant no. 0452995), and the Wenner-Gren Foundation for Anthropological Research (grant no. 7330). J.S. acknowledges the Brazilian national Research council (cnPq) and State of Amazonas Research Foundation (FAPeAM) Peld Program grants (cnPq 441811/2020-5 and FAPeAM 01.02.016301.02630/2022-76). e.c. acknowledges funding from AdAgriF\u2014Advanced methods of greenhouse gases emission reduction and sequestration in agriculture and forest landscape for climate change mitigation (cZ.02.01.01/0 0/22_008/0004635). A.B. was supported by state funding contract \u2018Biodiversity and ecosystem Functions of Forests\u2019 (124013000750-1).