Study On Population Dynamics And Diffusion Model Of Invasive Plant Spartina Alterniflora

Biological invasion has become one of the hot topics in global environmental research,and there are great threats and hidden dangers to the safety of the ecological environment.In particular,the invasion of alien plants in coastal areas is becoming more and more serious,and it continues to cause losses to human daily life and economy.Spartina alterniflora was first introduced into my country as an ecological species,and it has already had a serious impact on the local ecological environment in some coastal areas.Therefore,based on remote sensing data to carry out research on the temporal and spatial characteristics of Spartina alterniflora invasion,the evolution of landscape in the invasion area,and the prediction of the spread of Spartina alterniflora are of great significance and significance for the management and control of Spartina alterniflora and the coordinated development of service economy and ecology..Based on the Landsat and Sentinel series of images,this paper studies the dynamic changes and diffusion models of Spartina alterniflora population in Shanghai Jiuduansha Nature Reserve from 1995 to 2019.Firstly,the spectral and texture characteristics of the image object are integrated,and the object-oriented-support vector machine method is used to extract the distribution information of the Spartina alterniflora community;then based on the change characteristics of the landscape pattern and spatial expansion of Spartina alterniflora and other landscape types Analyze the expansion mode of Spartina alterniflora and other landscape types in 2015 and 2019 to construct an ANN-CA model to predict the spread and distribution of Spartina alterniflora in 2025.The results of this study can provide a theoretical and scientific basis for the expansion of Spartina alterniflora,landscape evolution,and prediction of the distribution and spread of Spartina alterniflora.The main conclusions of this paper are as follows:1)Based on the Sentinel and Landsat series of image data sources,based on the objectoriented-support vector machine classification algorithm to classify Spartina sylvestris,the extraction effect meets the accuracy requirements.2)Based on the six phases of remote sensing images from 1995 to 2019 to conduct dynamic monitoring of Spartina alterniflora remote sensing intrusion,the study found that the dynamic spread of Spartina alterniflora in Jiuduansha Nature Reserve is divided into four stages,namely the settlement stage and the stagnation stage.Phase,rapid growth phase and slow growth phase.3)From 1995 to 2019,Spartina alterniflora in Jiuduansha Nature Reserve mainly moved to the southeast in the direction of the center of mass.From the analysis of landscape scale,the landscape complexity of Spartina alterniflora continued to increase,and the aggregation and connectivity showed a tendency to increase first and then later In a stable state.4)The ANN-CA model constructed in this paper has a good simulation effect on the vegetation evolution of Jiuduansha Nature Reserve.The forecast results indicate that Spartina spartina in Jiuduansha further expands in 2025.However,the expansion rate has slowed down from a trend point of view,and its main diffusion direction is still competing with the sea clover to the southeast.Figure 25;Table 18;Reference 74...