A new study led by Prof. SHAO Hua at the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences has revealed that aridity and grazing jointly reduce the resistance of plant communities, thereby facilitating the invasion of Solanum rostratum in northern China. 

The study was published in Functional Ecology on Sept. 30.

In this study, the researchers conducted a national-scale field survey spanning 3,000 km across northern China, they investigated 40 representative sites to understand the influence of the biodiversity, functional traits and phylogenetic structure of native plant communities on invasion intensity.

They found that plant communities with higher biodiversity—especially those with greater phylogenetic diversity and functional complementarity—exhibited significantly lower invasion intensity of Solanum rostratum. High community diversity increases plant density, coverage, and biomass, and promoted resource-conservative traits, creating fewer opportunities for invaders.

However, arid climates and grazing pressures were linked to reduced biodiversity and trait complementarity, weakening these "biotic defenses" and making ecosystems more susceptible to invasion. In terms of predicting the resistance to invasion, the researchers found that the phylogenetic diversity and the Simpson index were more effective predictors than species richness.

"Our work indicates that conserving and restoring native biodiversity, with a specific emphasis on plants exhibiting resource-conservative traits, could strengthen ecosystem resistance under increasing climatic and grazing pressures," said SHI Kai, first author of the study.

This study supports Elton's biotic resistance hypothesis and highlights the crucial role of biodiversity—not just species richness, but also functional and phylogenetic structure—in resisting plant invasions.