Endangered plant stands on the shoulders of midgets

A plant's survival in the location can depend on the microscopic life in the soil.

The endangered plant Hypericum cumulicola survives as well as it does in Florida thanks to the soil microbiome say Aaron David and colleagues. “Our finding that soil microbiomes underlie population persistence carries important implications for conservation and management,” the authors write in their article, published in the October issue of The American Naturalist.

Hypericum cumulicola. Image: U.S. Fish and Wildlife Service

The authors say their results matter for two reasons. “First, it suggests that a plant species cannot be conserved without also conserving its accompanying natural soil microbiome. Second, such conservation of the soil microbiome is especially important in stressful habitat and for the species endemic to that habitat.”

Their work is consistent with work done independently on with metallic sun orchid of Australia, that requires certain fungi living in the soil of its home range.

Rather than looking at specific fungi, David and colleagues assessed the microbiome as a whole, using a bioassay and an integral projection model created from the bioassay data. They found that the microbes played an important role in seed germination, possibly by increasing soil moisture.

In their paper, the authors argue that microbes can reduce stress for a plant, allowing them to exist outside what would be their normal range. In their simulations, microbes enabled H. cumulicola populations to survive at higher elevations than they usually would.

“Soil amendments have long been used to reintroduce native microbes to degraded habitat…,” write David and colleagues. “Our findings suggest that such amendments could help boost plant population growth rates, particularly for species whose germination both responds positively to soil microbes and is critical to its demography.”

Further reading

David, A. S., Quintana-Ascencio, P. F., Menges, E. S., Thapa-Magar, K. B., Afkhami, M. E., & Searcy, C. A. (2019). Soil Microbiomes Underlie Population Persistence of an Endangered Plant Species. The American Naturalist, 194(4), 488–494. https://doi.org/10.1086/704684