Abstract: To explore the effects of invasive species on the leaf functional traits of native species, species richness, individual abundance, biomass, and leaf functional traits of native plant species were investigated under different invasion pressures (no invasion, mild invasion, and severe invasion) of invasive species Amaranthus retroflexus with insitu investigation and laboratory analysis. The results showed that species richness, number of plants, and aboveground biomass of native species decreased gradually with increasing invasion pressure. Under the severe invasion pressure, nitrogen content (N_mass) of A. retroflexu was significantly increased, while carbon content (C_mass), C/N ratio, and leaf construction cost (CC_mass) were significantly decreased, and no significant change of specific leaf area (SLA). Native species had lower C_mass and C/N, and higher SLA. Under the mild invasion pressure, there were no significant differences in of all examined traits between A. retroflexu and the native species. For A. retroflexus, N_mass was significantly negatively correlated with C/N and C_mass, but not with SLA. For native plants, N_mass was significantly negatively correlated with C/N and significantly positively with SLA, while the correlation with C_mass was not significant. Our results suggested that higher resource utilization efficiency and lower resource capture costs were the main reasons responsible for the successful invasion of A. retroflexus.

Key words: Great Xing’an Mountains, surface dead fuel, meteorological element regression., moisture content