Climatic controls of decomposition drive the global biogeography of forest-tree symbioses

Journal Article · Wed May 15 00:00:00 EDT 2019 · Nature (London)

DOI:https://doi.org/10.1038/s41586-019-1128-0· OSTI ID:1524787

Steidinger, B. S. ^[1]; Crowther, T. W. ^[2]; Liang, J. ^[3]; Van Nuland, M. E. ^[1]; Werner, G. D. A. ^[4]; Reich, P. B. ^[5]; Nabuurs, G. ^[6]; de-Miguel, S. ^[7]; Zhou, M. ^[8]; Picard, N. ^[9]; Herault, B. ^[10]; Zhao, X. ^[11]; Zhang, C. ^[11]; Routh, D. ^[2]; Peay, K. G. ^[1]

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1. Stanford Univ., CA (United States)
2. Swiss Federal Institute of Technology (ETH), Zürich (Switzerland)
3. Purdue Univ., West Lafayette, IN (United States); Beijing Forestry Univ. (China)
4. Univ. of Oxford (United Kingdom)
5. Univ. of Minnesota, Minneapolis, MN (United States); Univ. of Western Sydney, NSW (Australia). Hawkesbury Inst. for the Environment
6. Wageningen Univ. (Netherlands)
7. Univ. of Lleida (Spain); Forest Science and Technology Centre of Catalonia (CTFC), Solsona (Spain)
8. Purdue Univ., West Lafayette, IN (United States)
9. Food and Agriculture Organization of the United Nations, Rome (Italy)
10. Univ. of Montpellier (France); Institut National Polytechnique Félix Houphouët-Boigny (INP-HB), Yamoussoukro (Côte d’Ivoire)
11. Beijing Forestry Univ. (China)

The identity of the dominant microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools, sequester carbon and withstand the impacts of climate change. Characterizing the global distribution of symbioses, and identifying the factors that control it, are thus integral to understanding present and future forest ecosystem functioning. In this work we generate the first spatially explicit global map of forest symbiotic status using a database of over 1.1 million forest inventory plots with over 28,000 tree species. Our analyses indicate that climatic variables, and in particular climatically-controlled variation in decomposition rate, are the primary drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal (EM) trees, which represent only 2% of all plant species, constitute approximately 60% of tree stems on Earth. EM symbiosis dominates forests where seasonally cold and dry climates inhibit decomposition, and are the predominant symbiosis at high latitudes and elevation. On the other hand, arbuscular mycorrhizal (AM) trees dominate aseasonally warm tropical forests and occur with EM trees in temperate biomes where seasonally warm-and-wet climates enhance decomposition. Continental transitions between AM and EM dominated forests occur relatively abruptly along climate driven decomposition gradients, which is likely caused by positive plant-microbe feedbacks. Symbiotic N-fixers, which are insensitive to climatic controls on decomposition compared with mycorrhizal fungi, are most abundant in arid biomes with alkaline soils and high maximum temperatures. The climatically driven global symbiosis gradient we document represents the first spatially-explicit, quantitative understanding of microbial symbioses at the global scale and demonstrates the critical role of microbial mutualisms in shaping the distribution of plant species.

• Research Organization: Stanford Univ., CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Contributing Organization: GFBI consortium
• Grant/Contract Number: SC0016097
• OSTI ID: 1524787
• Journal Information: Nature (London), Vol. 569, Issue 7756; ISSN 0028-0836
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES