Effects of reforestation on plant species diversity on the Loess Plateau of China: A case study in Danangou catchment

Abstract

Large-scale vegetation restoration has important impacts on plant species diversity, which then influences plant community stability and resilience. The purpose of this paper is to compare the diversity of plantations as well as the diversity of artificially restored and naturally restored grasslands under different years of recovery and to identify the plots with the highest species diversity by vegetation type and restoration duration to determine strategies for vegetation restoration in hilly and gully regions of the Loess Plateau. Stands of Robinia pseudoacacia and Caragana korshinskii of different ages (10, 20, 30 and 40 years old) in the Danangou catchment on the Loess Plateau of China were selected as a case study to analysis effects of afforestation on the structure and function of ecosystems. The results showed that (1) under different numbers of years of recovery, the species diversity of woodland changes with changes in the coverage of woody plants, and the species diversity of R. pseudoacacia plantations planted on sunny slopes and R. pseudoacacia and C. korshinskii plantations planted on shady slopes reaches its maximum when coverage reaches a minimum value after 20 and 30 years of recovery, respectively; (2) soil moisture (in both shallow and deep layers) is the key factor controlling species diversity in woodlands, as the soil moisture changes with the coverage of woody plants following different numbers of years of recovery, which then influences the species diversity; (3) compared to the woodlands, the natural grassland exhibited higher species diversity under all recovery duration. Therefore, natural recovery is recommended if only species diversity is considered rather than human demand for wood, but if demand for materials is considered, we recommend thinning R. pseudoacacia on sunny and shady slopes at the ages of 10–20 and 10–30 years, respectively.