October 09, 2018

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Investigating the Impact of Tree Root Fungus on Leaf Litter Decay in Contrasting Climates

Leaf litter decay rates differ between mycorrhizal groups in temperate, but not tropical, forests.

The Science

Leaf litter decay data from previous studies combined with previously unavailable data from the TRY global plant traits database were used to determine the effect of tree root fungus on litter decay at varying latitudes. The goal of the study was to determine the difference in litter decay rates for temperate and sub/tropical forests.

The Impact

Distinctions between the effects that varying types of tree root fungus have on leaf litter may improve predictions of species effects on ecosystem processes, particularly in temperate forests where the two primary fungus species commonly co-occur. This would lead to a better predictive framework for linking litter quality, organic matter dynamics, and nutrient acquisition in forests.

Summary

There are two primary types of root fungus associated with trees; arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM). The researchers of this paper hypothesized that AM litters would decompose quicker than ECM litters throughout all latitudes of Earth but instead found that while AM litters decomposed more quickly than ECM litters in temperate forests, this pattern weakened at lower latitudes (i.e. sub/tropical forests). This shows that root fungal type is not necessarily a direct influencer of litter decay but more likely an indirect contributor to some of the many factors controlling litter decay with varying degrees of influence throughout latitudes.

Principal Investigator

Joshua Fisher
University of California, Los Angeles/NASA Jet Propulsion Laboratory
joshbfisher@gmail.com

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

U.S. Department of Energy, Office of Biological and Environmental Research, Terrestrial Ecosystem Science Program and National Science Foundation Ecosystem Science.

References

Keller, A. B., and R. P. Phillips. "Leaf litter decay rates differ between mycorrhizal groups in temperate, but not tropical forests". New Phytologist 222 (1), 556–64  (2019). https://doi.org/10.1111/nph.15524.