Changes in species diversity and above-ground biomass of shrubland over long-term natural restoration process in the Taihang Mountain in North China

Abstract

In order to restore the impaired forest ecosystem in China, great efforts including the banning of the animal grazing and cutting woods for fuel, and implementation of the ‘Grain for Green’ program have been made by the central and local government of China. The objective of this research was to investigate the changes in above-ground biomass and species diversity after 22 years of vegetation recovery efforts in the lower Taihang Mountain of China. The results indicated that over the natural restoration process shrubs became the dominant species in 2008, while herbs were the dominant species back in 1986. Community coverage, height and above-ground biomass showed significant increases in 2008 compared to 1986. Shrubs showed significant increases in coverage, height, and above-ground biomass, whereas herbs significantly increased in height, but decreased in above-ground biomass. Over the 22-year natural restoration process, the species richness index and the Shannon-Wiener’s index had been significantly decreased, whereas the Simpson’s predominance index and the Pielou’s evenness index had been significantly increased. Long-term vegetation recovery efforts improved the impaired forest ecosystem in lower Taihang Mountain to some extent: significant increases in both community coverage and above-ground biomass. The significant increase in community coverage can reduce the soil loss by wind and water erosion, and increase in the above-ground biomass will improve the soil chemical properties and physical structure. A comprehensive assessment of the success of vegetation recovery should include the evaluation of the changes in ecological process such as soil biological activities in the future research.