How is biodiversity changing in response to ecological restoration in terrestrial ecosystems? A meta-analysis in China.

Biodiversity is an important ecosystem characteristic, and is vital for maintaining ecosystem health and stability. However, biodiversity was often ignored in previous Chinese restoration planning and design due to its complex roles and the unclear mechanisms in providing human well-being. In order to evaluate the response of biodiversity to ecological restoration in terrestrial ecosystems, we assembled biodiversity in different metrics and different organisms and generated a large dataset comprised 2099 observations from 103 published studies to conduct a meta-analysis in China. Our results revealed that the biodiversity of restored ecosystem increased by 43% compared with degraded state, but it was difficult to recover to the natural level across the whole China. The gap between restored and natural ecosystems was about 13%. Ecological restorations have contributed not only to increasing vegetation coverage but also to improving soil environment and habitat quality. The recovery levels of vascular plant, soil microorganism and soil invertebrate were 30%, 73% and 48%, respectively. Biodiversity recovery would be better reflected in enhancing the structure feature (65%) such as plant height and density rather than the diversity feature (18%) such as diversity indices of Shannon and Simpson. Moreover, the response of biodiversity to ecological restoration varied with restoration actions (i.e., initial land use/cover type, restoration approach and restoration age), and the interaction effects among restoration actions significantly impacted biodiversity recovery. Passive approach performed better than active approach for biodiversity recovery. Meanwhile, the magnitude and direction of the impact of ecological restoration on biodiversity greatly altered with environmental conditions (i.e., climate condition and altitude). Our findings could facilitate priority setting and selection of treatment methods for biodiversity recovery during ecological restoration planning and assessment to ensure high effectiveness and sustainability.