Effect Of Landscape Pattern On The Prevalence Of Poplar Rust In Yanqing,Beijing

Based on the investigation of the damage status of Populus alba L.in Yanqing District,Beijing,this study explored the relationship between the landscape pattern and the disease epidemiology of poplar rust,explained the incidence of poplar rust in this region from the perspective of the landscape,and provided theoretical basis and policy recommendations for the prevention and control of the disease.The research carried out the investigation of poplar rust in 78 samples in the study area.According to the disease classification standards,the incidence of poplar rust was recorded and the disease index was calculated Based on the remote sensing image classification map of the research area,metrics at the landscape level and class level were calculated at the scales of 250m,500m,750m and 1000m in FragStats.Correlation analysis of landscape metrics and stepwise regression analysis of disease index between landscape metrics was implemented in R,and RDA analysis of class level was implemented in CanocoThe investigation indicates the following results1.The disease occurred frequently in the study area,with the disease index between 5.6 and 94.1 The severity of the disease was significantly affected by the landscape pattern,habitat environment,the geomorphological type and manual management status2.The metrics of landscape level has certain information redundancy,which needs to be screened in the analysis of landscape pattern.In this study,there are some differences in the correlation of landscape index of different scales,and landscape metrics of 500m scale is relatively independent.3.At the landscape level,landscape pattern of different buffers has different responses to the disease index,and the factors with significant influence are also different.The model is the best in 500m buffer,and the disease index can be reflected by the metrics of area,shape,aggregation degree and diversity.4.At the class level,cropland patches and grassland patches have significant impacts on the occurrence of poplar rust,which is mainly reflected in the common metrics such as PD and IJIThrough the analysis of the above results,the study found that the associated corridor and foundation provide convenient conditions for the spread of disease,which can promote the occurrence of poplar rust.The landscape pattern of 500m buffer is the optimal scale of disease management.Under this scale,the landscape metrics can establish a significant correlation with the occurrence of disease.Combined with the characteristics of poplar rust occurrence of pathology,this study explained the occurrence of diseases in the aspects of the area-shape,aggregation and diversity.The complexity of the shape of the patches inside the landscape and the level of diversity of the landscape will affect the occurrence of disease,and it will greatly promote the prevalence of disease with dispersed patches in the landscape,refined landscape structure as well as the uniform distribution between patches.