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Chang’an University (2018)

Study on the Evaluation of Grassland Desertification in Qiangtang Plateau

侯阁;

Titre : Study on the Evaluation of Grassland Desertification in Qiangtang Plateau

Auteur : 侯阁;

Grade : Master’s Theses 2018

Université : Chang’an University

Résumé
In the context of global climate change and human activities,the alpine grassland desertification is serious increasingly,moreover,the life of the residents is facing unprecedented challenges,therefore,it is of great significance to explore the desertification of the alpine grassland to the economic development of alpine plateau.In our study the remote sensing images from 1984 to 2013 year were analyzed via the method of landscape index,the object is to obtain the spatiotemporal dynamic distribution of desertification in the alpine meadow of Qiangtang plateau and the main driving factors.Meanwhile,the different gradients of the desertification,the driving factors of desertification and desertification restoration were selected to reflect the variation and analyze the internal mechanism of the desertification among biodiversity,above ground biomass,and soil nutrient status.Some results were shown as :(1)Spatiotemporal dynamic distribution of the desertification grassland in Qiangtang plateau ;The desertification grassland of Qiangtang plateau mainly distributed in the northern regions of the Qiangtang plateau,which occupied most of the study area.The desertification grassland was improved in the study period,but there is a potential desertification risk in Qiangtang plateau.The human activities were more significant driving factors than the environmental factors in the desertification of the alpine grassland in the Qiangtang plateau.(2)The correlation between the biodiversity,above ground biomass,and soil nutrient status in the desertification.The biodiversity and above ground biomass of alpine grassland increased firstly and then decreased under the desertification gradient in the study area.The soil water content,temperature,total carbon and available nitrogen played positive roles in the alpine grassland but pH.The soil compactness of desertification grassland has a promoting effect on above ground biomass but the biodiversity,and the soil temperature had a passive effect on above ground biomass and biodiversity via the method of direct impacting and the method of indirect impacting which based on the direct effect of the soil total carbon,organic carbon,total nitrogen and total phosphorus.(3)The study of the main driving factors of the desertification of alpine meadowThe main driving factors of the desertification of alpine meadow were the overgrazing and rodent in Qiangtang plateau.

Mots clés : Qiangtang plateau; Grassland desertification; Spatiotemporal dynamic evaluation; Biodiversity; Aboveground biomass;

Présentation (CNKI)

Page publiée le 22 avril 2019