Purpose

High-diversity communities may mitigate the impact of environmental changes on soil erosion owing to the compositional, structural, and functional diversity of their species. In this field study, we explored the relative contributions of these biodiversity components to soil erosion and the mitigating effects of each index under environmental changes (e.g., rainfall intensity).

Methods

We investigated the compositional (species diversity and evenness), structural (tree diameter and height diversity), and functional diversity (functional richness, evenness, and divergence) of 12 plant communities on Hainan Island, where biodiversity loss is severe. We measured soil erosion in each community using erosion plots under different rainfall intensities. The direction and relative contribution of biodiversity indices to soil erosion were analyzed.

Results

Except for the functional evenness, high values of biodiversity indices were associated with significantly reduced soil erosion regardless of rainfall intensity, and the relative contribution of tree height diversity was greater than that of other biodiversity indices. In addition, multiple biodiversity factors alleviated the adverse effects of increased rainfall intensity on soil erosion, but plant structural diversity had a greater positive effect than compositional and functional diversity, predominantly because of tree height diversity.

Conclusions

The results confirmed that the consideration of multiple biodiversity components provides an improved understanding of the relationship between biodiversity loss and soil erosion. We emphasize that protection of tree height diversity may not only effectively reduce current soil erosion, but also resist the adverse impact of increased rainfall intensity on soil erosion in the future.