| Zhalong Nature Reserve possesses the reputation of “birds' paradise,cranes' hometown”,which mainly protects the rare waterfowl wildlife such as the Red Crowned Crane and its living environment of the wetland ecosystem.Based on the basic theory of landscape ecology,Zhalong Nature Reserve was taken as the research area and computer application software,such as: GIS,ENVI,was also used in this study in order to extract the feature of the remote-sensing image in the research area from 1984 to 2010.Besides,through the decision tree method,remote-sensing images were made a landscape classification.Then,the characteristic curve of the landscape's change trend was drawn by using the landscape index method.The wavelet analysis of the signal source was also carried out to explore the laws and trends of the dynamic changes in the landscape.Meanwhile,the main driving factors which resulted in the dynamic changes on different time scales were also investigated.The results are as follows:(1)From 1984 to 2010,the characteristics of landscape dynamic change of Zhalong wetland are obvious.In 1984,wetlands were mainly distributed in the midland and mainly dry land in the peripheral.The main landscape type was a wetland swamp.And in 2010,the dry land expanded while the wetland reduced drastically,which mainly distributed in the southern region.Its distribution was fragmented,and the main landscape type transmitted from the wetlands to dry land.As the original wetland area in the protected area is gradually reduced and the area of cultivated land increases year by year,the complexity of the landscape has a significant reduction.Due to the changes of natural conditions and the impact of human activities,wetland type of landscape fragmentation intensified.At the same time,the landscape within the interference intensity is also increasing.(2)The dynamic changing characteristics of Zhalong wetland landscape are periodic and regular,and the dynamic changes of landscape are not disorderly in long time series.Influenced by natural factors,the dynamic change of landscape has significant correlation with the succession of natural conditions.The research finds that fragmentation,complexity and diversity have something in common--the characteristics of main periods are all in the time scale of 22 years,and the period of variation ranges from 5years to 7years.(3)Through the analysis and comparison of natural factors and human factors,the changes of four kinds of elements,such as precipitation,runoff,ditch and reclamation of wetland,and the change and influence of environmental factors are accordance with the change of landscape dynamic curve and its development trend.The four elements are the main driving forces of wetland landscape's change,which have promoted the development process of landscape dynamic change to varying degrees.And on the large time scale,the natural factor is the main driving force to promote the landscape's change.What's more,the human factor changes the trend and intensity of the landscape change.On the scale of small time and space,the natural factor is the binding force of the dynamic trend of landscape,and the driving factor of human is the direct driving force of landscape's change.Based on the analysis of landscape dynamic changing curve,this paper explores the regularities of landscape dynamic change and analyzes the driving factors that cause its periodical variation.It finds that natural factors influence the direction and trend of landscape dynamic change,while human factors affect the intensity and regularity of landscape dynamic change.Strengthening the research on the driving mechanism of wetland landscape dynamic changes is useful to predict the future dynamic change of wetlands,and guarantee the restoration of ecological environment,the management and protection of wetland resources.Meanwhile,it is important basis for the sustainable development of regional society and economy. |
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