Relationship Between Plant Functional Groups,Species Richness and Community's Productivity in Degraded Grassland

In order to investigate how functional groups change after degradation,the relationships between species richness and community's productivity were analyzed using community survey and spatial-temporal substitution methods in different degraded Kobresia humilis meadow of Dari County in Qinghai province.Results showed that moderately degraded meadow had the highest species richness and diversity index;the slight degraded meadow followed and the heavily degraded meadow had the lowest.The community's productivity was the greatest in slightly degraded meadow and is inconsistent with the tendency of species richness and diversity index having no significant correlation between them.Additionally,different plant functional groups showed a different variation.Along with grassland degradation increase,the biomass of forbs increased,while the biomass of leguminosae and the sedge decreased,and the biomass of gramineae showed a low-high-low tendency.Correlation analysis showed that the biomass of plant functional groups had no significant correlation with the species number of plant functional groups.