Abstract:

Reconstruction of plant communities with native shrubs is one of principle important ecological modes in superhighway side slope protection. In a case of Yongchuan region along Chengyu expressway, two typical vegetation configuration modes, i.e. Bambusa emeiensis+ Buchloe dactyloides and Rosa xanthina + Lolium perenne, were used as the foundation for slope protection in southwest areas. Two native shrubs, Amorpha fruticosa and Vitex negundo, and two herbs, Cynodon dactylon and Miscanthus sinensis, were chose to plant with the different modes and growth proportion. The characteristics of slope runoff and sediment erosion in rainy seasons were measured in a plot experiment during 2010 to 2012 to study effects of pioneer species richness on growth and development of plant communities on highway slope, the early successional and the slope protection performance. Results showed: 1) Pioneer plants richness affected accumulation of vegetation biomass and period of turf-establishment, and the more abundant pioneer plant species, the shorter turf-establishment period and more accumulation; 2) Richness of pioneer plants were closely related to plant species diversity in the communities with determination coefficient in excess of 0.995 (P<0.05). At the same succession stage, the more abundant pioneer species, the higher plant species diversity including the number of species, Shannon-Wiener index and Pielou index in the communities; 3) There was a positive correlation between the soil and water conservation capacity of vegetation and plant species diversity in the communities with determination coefficient in excess of 0.995 (P<0.05), and the higher plant species diversity, the stronger capacity the soil and water conservation with the smaller runoff coefficient and lower soil erosion modulus. Our results suggested that an increase in pioneer plant species richness should be a feasible way to improve ecological slope protection, especially when there were same side slope conditions, seed quantity and planting measures.

Key words: pioneer plant, plant species diversity, soil and water conservation, ecological slope protection