In natural ecosystems, species-rich native plant communities are generally more resistant to invasions by non-native species compared to species-poor ones. However, the role of non-native plant diversity in influencing the establishment and spread of subsequent invaders, particularly under varying environmental conditions, remains poorly understood.

Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences conducted a controlled experiment to investigate how soil conditioned by varying levels of non-native plant diversity affects the growth of six non-native plant species under both well-watered and drought conditions.

The study revealed that species-rich non-native plant communities significantly increased the abundance of arbuscular mycorrhizal fungi (AMF) in the soil. This microbial enrichment facilitated the growth of subsequent non-native plants under well-watered conditions, suggesting a positive feedback loop. Specifically, high non-native plant diversity promotes AMF proliferation, which in turn enhances soil conditions for further non-native plant establishment and growth, particularly in favorable environments.

However, this positive relationship between non-native plant diversity and invasibility was not observed under drought conditions. The researchers found that environmental stress, such as drought, disrupts this feedback loop, highlighting the critical role of abiotic factors in mediating plant invasion dynamics.

These findings provide new insights into the complex interactions between soil microbial communities, environmental stress, and the invasibility of non-native plant communities. The study emphasizes the importance of considering environmental stressors, particularly drought, in the management and mitigation of plant invasion risks.

The research was supported by the National Natural Science Foundation of China and has been published in New Phytologist.

Overview of the experimental design (Image by WBG)

Soil microbial legacies generated by three levels of non-native species diversity (Image by WBG)