Plant diversity increases the abundance and diversity of soil fauna with species richness

Yakun Zhang, Sai Peng and Han Y. H. Chen, Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada, Xinli Chen, Faculty of Natural Resources Management, Lakehead University, Thunder bay, ON, Canada

Background/Question/Methods
Soil fauna communities are an important component of soil biodiversity, which is key to myriad terrestrial ecosystem processes. However, despite the current alarming loss of plant diversity, it remains unclear how plant diversity affects soil fauna communities. By synthesizing 629 paired observations of plant mixtures and corresponding monocultures from 38 studies, we examined the effects of plant mixtures on soil fauna abundance and diversity. Further, we investigated the dependence of mixture effects on the species richness, stand age, climate conditions, and ecosystem types.
Results/Conclusions
We found that, on average, the abundance and diversity of soil fauna did not differ significantly between plant mixtures and corresponding monocultures. However, the mixture effects on both soil fauna abundance and diversity increased with the plant species richness in mixtures, which resulted in a significantly higher abundance and diversity of soil fauna in species-rich plant mixtures. While the effects of plant mixtures on the abundance and diversity of soil fauna were not altered with stand age on average, the effects on soil fauna abundance increased over time in diverse species mixtures. Although the effects of mixtures did not differ significantly between grasslands and forests, their positive effects on soil fauna abundance were more pronounced under drier conditions. Our analysis highlights the importance of plant diversity conservation for the maintenance of soil fauna communities.