Linking plant functional trait diversity and community structure characteristics in a seasonal grazing alpine meadow on the eastern Qinghai-Tibet Plateau
Seasonal grazing is a common grazing practice in the alpine meadows of the eastern Qinghai-Tibet Plateau.The composition and structure of plant communities may vary when grazing in different seasons;thus,functional traits may also be adjusted to accommodate long-term seasonal grazing disturbances,although it is not yet known whether there is a link between the two.In this study,we selected the cold season(November to April of the following year)and warm season pastures(June to October)in alpine meadows on the eastern Qinghai-Tibet Plateau with a long-term seasonal grazing history of over 10 years to investigate plant community characteristics and functional traits(plant height,biomass,and leaf traits)of their dominant species and study the association between plant functional trait diversity and community structural characteristics.The results showed that the evenness of plant community characteristics was significantly higher(P＜0.05)and community height was lower(P＜0.05)during warm season grazing than during cold season grazing.The species composition of the plant communities differed between the different grazing seasons.Alpine communities inhabited 43 and 37 species belonging to 15 and 13 families,respectively,in the cold and warm grazing seasons.Forbs had the largest importance values of plant communities in both cold and warm seasons,but no significant difference in the importance values of grasses between the two seasons.However,the importance values of sedges and legumes were higher in the warm grazing season than those in the cold season.The specific leaf area,leaf dry matter content,and leaf distribution of the long-term warm season grazing plants were significantly higher(P＜0.05)at the community level than those in the cold season.The values of interspecific variation among traits revealed a tendency for interspecific variation in plant leaf traits to be higher under warm season grazing than under cool season grazing,with significant differences in individual plant height,biomass,specific leaf area,and leaf dry matter content(P＜0.05).At the same time,the functional richness values in warm season grazing were significantly higher than those in cool season grazing(P＜0.05).This indicated that plants invested more in leaves under long-term warm season grazing and leaf and individual plant height traits were more abundant and varied.Leaf and induvial plant height traits improved the efficiency of plant use of light and spatial resources.The plant community structure tended to be concentrated under warm season grazing,while it was dispersed under cold season grazing.This may be due to competition for lateral investment in plants during warm season grazing.Plant functional traits were more sensitive to seasonal grazing than to community diversity,and plant community characteristics tended to be dwarfed and concentrated under warm season grazing,with more functional diversity and more intense interspecific competition.Thus,warm season grazing improved the efficiency of plants using spatial and light resources compared to cold season grazing.This study explains the life history responses of plants under different grazing scenarios and the links between functional traits and community characteristics that can provide a theoretical basis for the sustainable development of grazing ecology in alpine meadows on the Qinghai-Tibet Plateau with rational seasonal grazing pastures and cyclical alternations of cold and warm season pastures.
万方数据
维普
