Oak trees found to help competing plant species coexist by reshaping soil ecosystems

Researchers have uncovered a mechanism that helps rival plant species coexist in the same habitat, finding that oak trees can alter soil conditions in ways that prevent dominant species from overwhelming weaker competitors. The study, published in the journal Ecology Letters, suggests that soil beneath oak trees acts as a natural mediator, promoting biodiversity and maintaining ecological balance.

A team led by Ezequiel Antorán and Joaquín Calatayud at the Global Change Research Institute found that Pyrenean oak trees modify the chemical and microbial composition of surrounding soils. Experiments showed that these altered soils reduced the germination success of the dominant gum rockrose while improving growth conditions for the less competitive laurel-leaf rockrose. Researchers said compounds released through oak roots and decomposing leaves, together with specialized soil microorganisms, appear to drive the effect.

To determine whether these interactions could sustain coexistence over time, the team developed computer simulations using data from field and laboratory experiments. The models accurately reproduced plant distribution patterns observed in nature, with laurel-leaf rockrose clustering near oak trees and gum rockrose dominating areas farther away. Simulations indicated that both populations could remain stable for at least 100 years, supporting the idea that indirect soil-mediated interactions play a critical role in maintaining biodiversity.

The findings, based on research conducted in the Central Mountain Range of Spain and supported by modeling work at IceLab, highlight the importance of ecosystem “mediators” such as oak trees. Researchers said understanding these hidden interactions could help guide habitat restoration, biodiversity conservation, and predictions of how plant communities may respond to climate change and species loss.

Source: Phys.org