Changes in plant functional groups and species diversity under three grassland using modes in typical grassland area of Inner Mongolia, China

Abstract

Aims Our objectives were to reveal changes in plant functional groups and species diversity under three grass-land using modes in typical steppe of Inner Mongolia, China. Methods Three plots in similar habitats were selected from the Hulunbeier steppe area of the Hui River National Nature Reserve: an meadow plot (controlled utilization), pasture plot (moderate utilization) and public pasture plot (severe utilization). Plots were 250 m × 250 m and consisted of three sample belts separated by 20 m. Each sample belt had eight 1 m × 1 m sample plots. Important findings There were differences in species composition and community characteristics of the func-tional groups. Shrubs and sub-shrubs combined were significantly different (p 0.05) among the plots, with the highest value in meadow. Perennial grasses were significantly different (p 0.05). Annual and biennial herbs combined had significant differences (p 0.05), with the highest value in the public pasture. The public pasture also had the highest percentage of the xerophyte functional group (50%) and the lowest mesoxerophyte and meso-phyte (19%), and differences were significant (p 0.05) among the plots. The biomass of shrubs and sub-shrubs were lower in all plots. The combined biomass of perennial grasses and forbs decreased with the increase in grassland use intensity among meadow, pasture and public pasture, while the combined biomass of annual and biennial herbs increased. With the increase in use intensity, the community structure and composition tended to become simplified and susceptible to change. Richness and diversity were lowest in the pasture and highest in meadow. Differences in evenness were not significant. The use of meadow contributed to improving the health of the grassland, but pasture and public pasture exhibited over-grazing phenomena. The public pasture had degraded significantly because of the uncertainty about property responsibility and ineffective management.