November 07, 2019

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Soil Carbon Stocks Globally Are Determined by Root Fungus Association

Global mycorrhizal plant distribution is linked to terrestrial carbon stocks

The Science

The relationship that plants form with root fungus is most often mutually beneficial, but sometimes can be harmful and growth-stunting to the plant. This study demonstrates that a particular type of root fungus, ectomycorrhiza (EcM), generally “walks the line” between mutualism and parasitism versus other species of fungus. Because EcM usually require more sugars (carbon) in return for the nutrients they scavenge for the plant, the fungus and root system tend to grow larger, while aboveground mass of the plant remains smaller. This paper shows that root fungus association is related to carbon stocks above- and belowground on a global scale, while also demonstrating the negative impacts agriculture may have on belowground carbon stocks.

The Impact

Despite a high demand for data on plant-fungal relationships, this study is the first to synthesize plant-fungal associations into a global distribution map based on field data. It is becoming more and more evident that plant-fungal associations are essential for understanding how nutrients are cycled and stored in the ecosystems. Inclusion of plant-fungal distributions into vegetation models could provide a benchmark for testing hypotheses about how fungi affect ecosystems.

Summary

The plant-fungal distribution maps were derived from land vegetation cover maps. With information about which species of plants typically inhabit a land cover type on a specific continent and which fungus typically colonizes that species the authors were able to derive the global distribution. Changes and losses in fungal colonization illustrated by this map could have a strong negative effect on carbon stocks, ultimately leading to less healthy soils and ecosystems.

Principal Investigator

Joshua B. Fisher
UCLA, JPL
[email protected]

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
[email protected]

Funding

DOE BER Environmental System Science (formerly Terrestrial Ecosystem Science) program and the NSF Ecosystem Science program.

References

Soudzilovskaia, N.A., et al. "Global Mycorrhizal Plant Distribution Linked to Terrestrial Carbon Stocks." Nature Communications 10 5077  (2019). https://doi.org/10.1038/s41467-019-13019-2.