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Lanzhou Jiaotong University (2020)

The Stability of Patchy Vegetation in the Desert-Oasis Transition Zone in the Middle Reaches of Heihe River Under Human Disturbance

张钰佳;

Titre : The Stability of Patchy Vegetation in the Desert-Oasis Transition Zone in the Middle Reaches of Heihe River Under Human Disturbance

Auteur : 张钰佳;

Grade : Master’s Theses 2020

Université : Lanzhou Jiaotong University

Résumé partiel
The desert-oasis transition zone in the middle reaches of the Heihe River is located at the junction of the Badain Jaran Desert and the Zhanglingao Oasis,and plays an extremely important role in resisting the dangers of wind and sand and maintaining the stability of the oasis.Due to some unreasonable human activities such as woodcutting and grazing by the local people,the desertification continued to expand and the ecological environment in the transition zone deteriorated further.In recent years,in order to prevent wind and fix sand and improve the regional ecological environment,local people have carried out a large number of replanting of sand-fixing vegetation in the transition zone.However,under this kind of human disturbance(mainly to replant sand-fixing plants),the evolution direction of regional vegetation stability has become the primary concern of the academic community.In this paper,the desert vegetation in the desert-oasis transition zone is taken as the research object.Based on the analysis of the dynamic changes of the vegetation landscape,the changes of the vegetation stability in the transition zone are evaluated from the perspective of time and space.At the same time,combined with the changing characteristics of regional environmental factors,the relationship between environmental factors and vegetation stability changes was analyzed.To further accurately assess the trend of regional vegetation stability under human interference,and provide a theoretical basis for the protection of natural vegetation in the area and the reasonable spatial allocation of artificial vegetation communities.The conclusion of the study is as follows :(1)According to the information on the change of the patch area and the bare patch area of the vegetation in the study area(Haloxylon ammodendron,Nitrarias sphaerocarpa thorn and Calligonum chinense),the vegetation area shows an increasing trend.Among them,the annual increase rate of Calligonum chinense was relatively large,which was 10.94% ;the area of bare land showed a decreasing trend,with an annual decrease rate of 5.28% ;from the analysis of landscape transfer matrix,it can be seen that the area of bare land converted to Haloxylon ammodendron was the most prominent during the study period.Up to 2.57 hm 2.The conversion of bare land into Nitrarias sphaerocarpa and Calligonum chinense was relatively large,0.04 hm 2 and 0.42 hm 2,respectively.In summary,the area of vegetation in the study area increases year by year,and the area of bare land decreases year by year.

Mots clés : Desert-oasis transition zone; human disturbance; vegetation stability; environmental factors;

Présentation (CNKI)

Page publiée le 22 mai 2021