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Accueil du site → Doctorat → Chine → 2020 → The Relationships between Biodiversity and Productivity of Grassland and Xerophytic Shrub Ecosystems on the Mongolian Plateau

Université de Mongolie-Intérieure (2020)

The Relationships between Biodiversity and Productivity of Grassland and Xerophytic Shrub Ecosystems on the Mongolian Plateau

李紫晶;

Titre : The Relationships between Biodiversity and Productivity of Grassland and Xerophytic Shrub Ecosystems on the Mongolian Plateau

Auteur : 李紫晶;

Grade : Doctoral Dissertation 2020

Université : Université de Mongolie-Intérieure

Résumé
The relationships between biodiversity and ecosystem functioning(BEF)have been critical topics in ecological research during recent decades.Community productivity,as an important component of ecosystem functioning,is fundamentally vital for nearly all ecosystem goods and services.Although the relationships between biodiversity and productivity have been extensively studied,there remain an ongoing debate about the magnitude and directions of their relationships.Especially in natural ecosystems,biodiversity,productivity and their relationships are comprehensively affected by environmental factors(climate,soil,etc),community composition and research scale,thus show a more complex and uncertain relationship.Mongolian Plateau located in an arid and semi-arid area,is sensitive to global climate change,with obvious environmental gradients,multiple vegetation types,and diverse species composition.Therefore,it is an ideal place to study the BEF in the natural ecosystem.Studying the influence of environmental factors on the BEF relationships in natural ecosystems is of great significance for understanding ecosystem stability maintenance mechanism and responses of natural vegetation to global climate change and could provide useful information for the conservation,utilization and management of natural ecosystems.In the present study,the data of plant community,climate and soil properties were used to analyze the effects and mechanisms of environmental factors on the biodiversity,community biomass and their relationships in grassland and xerophytic shrub ecosystems on the Mongolian Plateau.The Random Forest model was used to screen the most important environmental factors affecting the biodiversity and community biomass,and then the Structural Equation Model was fitted to analyze the impact of environmental factors on biodiversity,community biomass and their relationships.Herbaceous plants in the grassland communities are divided into different plant functional groups,and the role and mechanism of community composition in regulating the influence of environmental factors on biodiversity and community biomass are explored.The main conclusions are as follows:1)Climatic factors are the most important environmental factor affecting the community biomass of the Mongolian plateau grassland and xerophytic shrub ecosystems,but the main indicators differ between ecosystems.Aridity index(i.e.,the coupling of precipitation and temperature in a large-scale spatial range)and the mean temperature in the coldest quarter are the most important climatic factors affecting the biomass of grassland and shrub communities,respectively.

Mots clés : Species richness; Community biomass; Aridity index; Soil physical and chemical properties; Plant functional groups;

Présentation (CNKI)

Page publiée le 23 octobre 2020