Relationships between plant community productivity and diversity vary with trampling disturbance in an Inner-Mongolian steppe

The relationship between diversity and productivity of plant communities is an important issue in grassland restoration. However, the degree to which this relationship varies during the restoration stage after trampling disturbance is not clear. Here, we conducted a five-year study in a steppe after 4-year trampling to detect restoration patterns of plant community and investigate variation in diversity-productivity relationships. Our results showed that community cover, abundance, height, and productivity recovered quickly after the trampling disturbance ceased. However, the recovery of diversity was slower than biomass in the steppe. In addition, grass, annual, and biennial recovery was more rapidly than the recovery of forbs in the steppe. Moreover, following the restoration process, the positive correlation between productivity and diversity was decoupled, and a negative correlation between productivity and diversity developed. Our finding provides the key evidence for the asynchronous relation between productivity and diversity, and reveals that grass restored more rapidly than forbs in plant community restoration after disturbance. This study indicates that the trade-off between plant community structure and function can vary with the restoration process, and implicates that future modeling and experimental studies should focus on the different responses of productivity and diversity in plant community restoration.