Mapping microbial symbioses in forests

Data collected from over 1 million forest plots reveals patterns of where plant roots form symbiotic relationships with fungi and bacteria.

 

In and around the tangled roots of the forest floor, fungi and bacteria grow with trees, exchanging nutrients for carbon in a vast, global marketplace. A new effort to map the most abundant of these symbiotic relationships – involving more than 1.1 million forest sites and 28,000 tree species – has revealed factors that determine where different types of symbionts will flourish.

The work could help scientists understand how symbiotic partnerships structure the world’s forests and how they could be affected by a warming climate.

Stanford University researchers worked alongside a team of over 200 scientists to generate these maps, published May 15 in Nature.

The group used their map to predict how symbioses might change by 2070 if carbon emissions continue unabated. This scenario resulted in a 10 percent reduction in the biomass of tree species that associate with a type of fungi found primarily in cooler regions.

The data behind this map represents real trees from more than 70 countries and collaboration between hundreds of researchers who speak different languages, study different ecosystems and confront different challenges.

“There are more than 1.1 million forest plots in the dataset and every one of those was measured by a person on the ground. In many cases, as part of these measurements, they essentially gave the tree a hug,” said Brian Steidinger, a Stanford University researcher. “So much effort – hikes, sweat, ticks, long days – is in that map.”