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Inner Mongolia Agricultural University (2021)

Dynamic Simulation of Vegetation Community and Evaluation of Ecosystem Health of Dune-Meadow Area in Horqin Sandy Land

曹文梅

Titre : Dynamic Simulation of Vegetation Community and Evaluation of Ecosystem Health of Dune-Meadow Area in Horqin Sandy Land

Auteur : 曹文梅

Grade : Doctoral Dissertation 2021

Université : Inner Mongolia Agricultural University

Résumé partiel
The cold and dry region represented by Eurasian grassland is very important to the sustainable development of the world or China.In the past few decades,due to the impact of human activities and climate change,the region has faced the risk of desertification caused by ecological degradation.In this paper,Horqin sandy land is selected for this study,and the dune-meadow area in the southeast edge of Horqin sandy land is taken as the research area.Based on a large number of vegetation and habitat factor data collected,structural equation model(SEM)was used to simulate the dynamic change process of vegetation community.According to the results of community dynamic analysis,a land cover classification system based on community scale suitable for desertification ecosystem health analysis was developed.Combined with vegetation phenology,habitat information and multi temporal remote sensing data,a decision tree suitable for long-time series land cover recognition in dune-meadow area was established.Based on the evaluation framework of vigor-organization-resilience-services(VORS),the ecosystem health temporal and spatial variation characteristics in the process of periodic changes of hydrological conditions were analyzed.Finally,the effects of natural factors and human activities on ecosystem health were quantified by constructing SEM.The main research results are as follows:1.Based on SEM,the influence of habitat conditions on the vegetation community composition and structure was analyzed.In the the process of model construction,the community was distinguished by the difference of important values of dominant plant species,and the community composition was reflected by richness and diversity.It is an innovation in the research of vegetation community composition and structure.The results showed that soil moisture and texture had the most significant effect on community composition in sand dune habitat.Under the condition of meadow habitat,the most significant effect on community composition is the topographic characteristics.In addition,the dynamic changes of vegetation community composition were simulated based on SEM statistical results.

Mots clés : Horqin Sandy Land ;Land cover ;Struetural Equation Modeling ;Multi temporal remote sensing data ;Decision tree ;Ecosystem health ;

Présentation (CNKI)

Page publiée le 18 février 2022