Abstract
One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal type, with ectomycorrhizal tree species exhibiting higher sapling densities with increasing adult densities than arbuscular mycorrhizal tree species. Moreover, we found evidence of positive CMDD for tree species of both mycorrhizal types. Collectively, these findings indicate that mycorrhizal interactions likely play a foundational role in global forest diversity patterns and structure.
Original language | English |
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Article number | 1066 |
Journal | Communications Biology |
Volume | 6 |
Issue number | 1 |
DOIs | |
Publication status | Published - 19 Oct 2023 |
Bibliographical note
AcknowledgementsFunding was provided by the Swiss National Science Foundation Postdoctoral Fellowship TMPFP3_209925 (C.S.D.), Swiss National Science Foundation Ambizione PZOOP3_17990 (C.A.), US National Science Foundation grant DEB-2024903 (J.A.L.), DOB Ecology and the Bernina Foundation (T.W.C., C.S.D.). We thank everyone involved in the collection of the vast quantity of data in the ForestGEO network (see Table S5 for site-specific acknowledgments). The authors also thank James Bever for his early contributions in establishing the measurement of conmycorrhizal density dependence as well as Jenna Luecke and Chrysa Chouliara for their assistance in creating Fig. 1.
Data Availability Statement
ForestGEO plot data are not available due to data privacy and sharing restrictions, but can be obtained upon request through the ForestGEO portal: http://ctfs.si.edu/datarequest/). Other data used in the study can be found in references cited in the Methods section.Code availability
All code used to complete analyses for the manuscript is available at the following link: https://github.com/c383d893/Fgeo_project_Tree. Data analysis were conducted and visualizations generated in R (v. 4.2.2) and the ETH Zurich Euler cluster.
Keywords
- Mycorrhizae
- Feedback
- Symbiosis
- Plants/microbiology
- Soil