The Science

The coexistence of plants in an ecosystem is regulated by resource availability and competition for those resources. Mycorrhizal fungi (MF), a root symbiont that helps plants obtain nutrients, can alter how plants compete for resources, which can alter patterns of plant coexistence. MF are found almost everywhere that plants grow, so leaving them out of climate models can cause inaccurate predictions of ecosystem patterns such as plant coexistence. Researchers recently developed a new mathematical model that includes MF for the first time.

The Impact

Because MF alter resource availability, it may seem obvious that they will alter plant coexistence. Until now, however, mathematical models did not include MF. Including MF in models will lead to better predictions, which can enable better understanding of patterns in nature and how they might be altered by climate change.

Summary

Mycorrhizal fungi can alter plant coexistence patterns by changing the host plant’s ability to compete for resources in the soil. How MF change plant coexistence patterns depends on how dependent the host plant and MF are on one another for survival, the rate at which plants and MF exchange nutrients, and how plant growth patterns respond to the cost-benefit ratio of their symbiotic relationship with MF. A new model, which explicitly includes MF, shows that there are tradeoffs to the symbiosis. At times, the carbon cost of MF is balanced by the increase in nutrient availability; however, it is also possible for the carbon cost to outweigh the nutrient benefits and for MF to become detrimental to the host plant’s growth. The balance of the symbiotic relationship can affect plant competition for resources, which can lead to changes in plant coexistence. This model will enable future empirical studies to form hypotheses in light of a better understanding of MF’s role in plant coexistence patterns.

Principal Investigator

Aimee Classen
University of Vermont
Aimee.Classen@uvm.edu

Program Manager

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

Funding

This work was supported by the Terrestrial Ecosystem Science program of the Office of Biological and Environmental Research, within the U.S. Department of Energy Office of Science, under Award Number DE-SC0010562.

References