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Ningxia University (2020)

Effects of Seasonal Rotational Grazing on Plant Functional Traits and Diversity of Desert Steppe

宿婷婷;

Titre : Effects of Seasonal Rotational Grazing on Plant Functional Traits and Diversity of Desert Steppe

Auteur : 宿婷婷;

Grade : Master’s Theses 2020

Université : Ningxia University

Résumé partiel
Plant functional traits and species diversity are important contents of biodiversity-ecosystem functions.In grazing ecosystems,the feeding of herbivores can change the structure of plant community species,which can also affect the functional traits and vegetation diversity of the communities.The functional traits of plants are the manifestation of plants adapting to the environment and was the result of plants adapting to the environment during evolution.The study of plant functional traits in grazing grasslands is of great significance for understanding the ecological strategies of plants adapting to the environment and formulating reasonablds for grase grazing methoslands.In the desert grassland of Yanchi County,Ningxia,the study set 4 types grazing method(with FY as control),which were including traditional time grazing(FG),delayed starting grazing(YG),early ending grazing(TG),and delayed starting early grazing(YT).Four rotation grazing methods in four areas in warm season,the characteristics of root and leaf functional traits,species diversity,and functional diversity changes of grassland plant communities under seasonal rotation grazing were studied,with which a view to provide a basis for the use of desert grasslands.The main conclusions were as follows :(1)The important value of Leymus secalinus increased,while those of Astragalus melilotoides and Convolvulus ammannii were decreased.The treatments with higher grazing frequency were significantly increased the important value of the annual biennial herb Artemisia scoparia.Grazing had no significant effects on the biomass of different functional species under each treatment.There was no significant difference between grazing and enclosure grassland in the coverage and density of community.The community coverage of TG and the community density YT were higher than that of the enclosure grassland,and YG treatment significantly reduced the community height.(2)The horizontal leaf traits of community in the FG treatment were the smallest.The TG and YG treatments significantly increased the leaf area of the community.All grazing treatments significantly reduced the leaf thickness of the community.The leaf area and leaf thickness of semi-shrubs significantly in FG treatment,and grazing significantly increased the specific leaf area of semi-shrubs.The leaf area of the biennial herb was the largest in the TG treatment,and grazing reduced the specific leaf area,leaf dry matter content and leaf thickness of the biennial herb.In each treatment,the changes of leaf dry matter content and leaf thickness were synergistic,and the plasticity index of leaf thickness is the smallest among leaf traits,which was considered as an inert index.Besides specific leaf area and dry matter content,there was a positive correlation among other leaf characters.

Mots clés : functional traits of leaves and roots; plant diversity; composite index; seasonal rotation grazing; desert steppe;

Présentation (CNKI)

Page publiée le 22 mai 2021