Spatial-temporal Change And Connectivity Analysis Of Wetland Landscape

As an ecological landscape rich in biodiversity—wetland,it have distinctive ecological structures and unique functions.The material security needed for human survival and development is inseparable from the rich resources it contains.With the strengthening of natural and human factors,the wetland landscape pattern and landscape connectivity have undergone tremendous changes,affecting the wetland stability and biodiversity,resulting in the failure to maximize the function and value of wetland ecosystems.This article selects Zhalong wetland landscape as the research object,based on mathematical morphology,graph theory and landscape ecology principles,with the help of software platforms such as Envi,ArcGIS,GuidosToolbox and Conefor Sensinode 2.6,the main use of morphological spatial pattern analysis methods is to Wetland landscapes in the study area are classified,on this basis,quantitative analysis of the dynamic changes of Zhalong wetland landscape based on the MSPA method from 1979 to 2017,and the core area of Zhalong wetland landscape from 1979 to 2017 is quantified by calculating the graph-based connectivity index Connectivity changes and evaluation of patch importance,provide some new ideas for landscape pattern optimization and wetland protection.It includes the following aspects:(1)Classification of wetland landscape classification based on MSPA.First,the Zhalong wetland landscape is binarized,and the morphological spatial analysis method is used to set different grain sizes and edge widths.According to different structures and functions,the Zhalong wetland landscape is divided into core areas,bridges,loops,branch lines,edges,and pores.Seven isolated islands,the research results show that the particle size is 30 m and the edge width is 30 m as the most suitable scale,which lays the foundation for the analysis of the wetland landscape pattern and the evaluation of the wetland landscape connectivity.(2)Analysis of changes in wetland landscape types based on the MSPA method.By categorizing the Zhalong wetland landscapes in nine periods from 1979 to 2017,the morphological spatial pattern method was used to quantitatively analyze the general trends of the Zhalong wetland landscape evolution over the past 38 years.The results of the study show that all types of wetland landscapes fluctuate from 1979 to 2017.Among them,the core area occupies the dominant position of Zhalong wetland landscape,and its changes affect the change of wetland landscape connectivity.From the perspective of landscape type conversion,most landscape types are converted to non-wetlands.This indicates that the landscape area of Zhalong Wetland decreased during the study period and the landscape connectivity decreased.(3)Connectivity analysis of wetland landscape based on graph theory.Using graph theory as the theoretical basis,the related indexes of landscape connectivity are selected for calculation.Comparing the change rules of landscape connectivity indexes under different distance thresholds,the maximum distance threshold for landscape connectivity analysis and evaluation of Zhalong wetland landscape is 2000 m,the most The threshold of good distance is 800m;from 1979 to 2017,the overall connectivity index and possible connectivity index of landscape patches in Zhalong wetland showed a trend of increasing first and then decreasing.The landscape connectivity of the Long Wetland has changed from strong to weak,and there are fewer and fewer patches of wetlands that contribute to the connectivity of the landscape;the patch area and patch importance are not absolutely positively related.Ecosystem landscape connectivity and landscape pattern dynamics When analyzing and optimizing landscapes,not only focus on large patches,but also small patches.