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Inner Mongolia University (2021)

Constrution and Evaluation of Desert Ecosystem Quality Evaluation System ——A Case Study of Alxa League in Inner Mongolia

王建

Titre : Constrution and Evaluation of Desert Ecosystem Quality Evaluation System ——A Case Study of Alxa League in Inner Mongolia

Auteur : 王建

Grade : Master These 2021

Université : Inner Mongolia University

Résumé
Real status of desert ecosystem couldn’t be precisely reflected in annual national ecosystem status assessment issued by ecosystem monitoring authorities.Therefore,this thesis selected Alxa League,a typical arid desert region in Inner Mongolia,as research region.According to inversion on MODIS remote sensing image data about 5years of 2000,2005,2010,2015 and 2020,and RSEI remote sensing ecological index,fractional vegetation cover(FVC),vegetation growth quality,vegetation productivity,temperature,humidity,vegetation drought index and other ecological indicators that could reflect ecological environment quality of Alxa League region were obtained.Based on the standardization and grading standards in the“Technical Standards for Evaluation of Ecological Environment Conditions”,the principal component analysis method(PCA)was used to establish desert ecological environment quality assessment index(EQAI),based on which the ecological environment quality of the desert ecosystem of the Alxa League in the past 20 years was evaluated.Simultaneously,the land-use type transfer-in/transfer-out matrix was introduced to analyze the relationship between changes in the ecological environment quality of the desert ecosystem and the land-use type conversion.It concluded the following research accomplishments :(1)EQAI for 5 years between 2000~2020 were showing no significant difference.Over the recent 20 years,ecosystem quality of Alxa League showed improving trend from west to the east.However,environment quality of Alxa League is not good.(2)Over the last 20 years,bare soil area reduces continuously ;forest and grass land area increases steadily ;farmland and artificial surface(surface caused by artificial construction activities,including urban residential areas,industrial minings,transportation facilities ;green land and water in constructions are not included),shrub land and wet land reduced in 2010,yet remain steady in the following years.Water area increased at first and then decreased,yet overall trend for the 20 years is increasing.(3)Taking land-use type matrix over the last 20 years into consideration,bare soil and grass land showed active transfer-in/transfer-out activity and large transfer amount.Grass land were mainly transferred into bare soil.Amount of transfer to other land types is controlled to less than 150 km2.Major type for transfer-in land is bare soil and wet land.Major transfer-in type for bare soil is grass land.Other land type increased by 326.35 km2 over the 20 years.(4)The change of ecological environment quality is strongly related to the change of land use type.Grass land transfer-out was dominant in regions with degraded ecological environment.Grass land were mainly transferred into bare soils with low ecological environment quality.Bare soil transfer-out is dominant in regions with promoted ecological environment,where bare soil was mainly transferred into grass land with high ecological environment quality.

Mots clés : ecological environment quality assessment ;GIS and RS ;principal component analysis ;land-use ;

Présentation (CNKI)

Page publiée le 26 octobre 2021