Climate change is shifting tree populations away from the soil fungi that sustain them

As our planet warms, many species are moving to different locations as their historic habitats become inhospitable. Trees are no exception – the normal ranges of many species are no longer conducive to their health, but their movement to new areas that can better sustain them is lagging behind that of other plants and animals.

Now scientists show that the reason for this delay can be found underground. A study published in PNAS shows that trees, especially those in the far north, can move into soils that lack fungal life to support them.

Most plants form underground partnerships with mycorrhizal fungi, microscopic, filamentous fungi that grow in the soil and attach to plant roots to supply plants with critical nutrients in exchange for carbon. Most large conifers in northern latitudes form relationships with a type of mycorrhizal fungi called ectomycorrhizal fungi.

“When we investigated the future of these symbiotic relationships, we found that 35% of tree-fungi partnerships that interact with tree roots would be negatively affected by climate change,” says lead author Michael Van Nuland, a fungal ecologist at the company. for the protection of underground networks (SPUN).

The authors found that the trees most at risk from this climate mismatch in North America are trees in the pine family. Areas of particular concern are the edges of species’ ranges, where trees often face the harshest conditions. Here, the authors found that trees with higher survival rates in these sites had more diverse mycorrhizal fungi, a sign that these symbioses may be critical in helping trees withstand the effects of climate change.

“Ectomycorrhizal fungi have a different relationship to climate than ectomycorrhizal trees,” says co-author Clara Qin, a data scientist at SPUN. “We find evidence that trees must account for these differences.”

The study sheds light on how climate change may affect symbioses. “While we expect climate-driven migration to be limited by abiotic factors such as space availability at higher latitudes and altitudes, we typically do not consider biotic constraints such as the availability of symbiotic partners,” says Qin.

“It is absolutely essential that we continue to work on understanding how climate change affects mycorrhizal symbioses,” says Van Nuland. “These relationships are the foundation of all life on Earth – it’s important that we understand and protect them.”

Provided by SPUN (Society for the Protection of Underground Networks)