Effects of human interference on species diversity and biomass of Eucalyptus grandis plantation in Cangping Mountain Park in Ya’an

Objective  This study aims to reveal the effects of human interference on species diversity and biomass in E. grandis plantations. Method  12 sample plots of E. grandis plantations (20 m×20 m) with different interference intensities were set up by typical plot method in Cangping Mountain Park in Ya’an City of Sichuan Province, to investigate the species composition, species diversity(richness index D, Shannon-Wiener index H, Simpson dominance index H', Pielou evenness index Jsw), and plant layer biomass. Result  There were 87 species of vascular plants belonging to 55 families and 82 genera. The number of species in E. grandis plantation decreased with increasing interference. The D, H and H' indices of tree layer and herb layer decreased with the increase of interference intensity. The D, H and H' indices of shrub layer reached the maximum under moderate disturbance. The difference of D and H indices in tree layer was significant (P＜0.05). With the increase of disturbance intensity, the biomass of each plant layer showed different changing trends. The tree layer had the highest volume (12.01 m3·hm−2) under moderate disturbance, while the biomass of shrub layer (394.533 kg·m−2) and herb layer (359.680 g·m−2) was the highest under light disturbance. The D index of tree layer and H' index of herb layer were significantly positively correlated with aboveground biomass and total biomass of herb layer (P＜0.05). The Jsw index of herb layer was significantly positively correlated with total biomass of herb layer (P＜0.05). Conclusion  Moderate disturbance will increase species diversity and biomass in E. grandis plantation. The relationship between species diversity and biomass is subject to human interference and natural conditions, and there is no fixed relationship. [Ch, 2 fig. 3 tab. 25 ref.]