Effects of plant diversity on soil erosion for different vegetation patterns

- The relationship between plant diversity and soil erosion is ambiguous.
- This relationship is negative within a homogenous vegetation pattern.
- This relationship is positive within a heterogeneous vegetation pattern.
- Vegetation and soil erosion processes are unified with each other.
- No vegetation factor has an isolated effect on soil erosion.

Vegetation effectively prevents soil erosion. However the relationship between plant diversity and soil erosion remains ambiguous under various environmental conditions. To explore the role that plant diversity plays in soil erosion, this study was conducted in the Three-River-Source region, located in the hinterlands of the Qinghai-Tibet Plateau, China. After examining 99 plots within the study area, and analyzing the soil 137Cs inventory within the plots, we found that with a greater number of plants distributed within an aggregation pattern, there was greater interception of the soil particles by the vegetation patch. This phenomenon results in a more developed vegetation patch that can support greater vegetation coverage and higher plant diversity than it previously could. Although a positive correlation exists between plant diversity and vegetation coverage, the relationship between the extent of soil erosion and plant diversity is modulated by the vegetation pattern. When plants are distributed in a relatively homogeneous pattern, vegetation coverage decreases with increasing plant diversity, which leads to increased soil erosion. When plants are distributed between a homogenous and a heterogeneous pattern, no relationship is found between plant diversity and soil erosion. With a heterogeneous plant distribution, vegetation coverage increases with plant diversity, and soil erosion is inhibited under such conditions.