Study On The Relationship Between The Characteristics Of Landscape Pattern And The Damage Of Poplar Herbivores In The Valley Of Irtysh River In Xinjiang

To explore the landscape pattern under different scale influence on forestry harmful biological occurrence and harm,this article takes the irtysh river valley,xinjiang area as the research object,using the remote sensing image and characteristics of the landscape pattern using landscape indices analysis,from two dimensions of landscape and landscape types,using generalized linear model(GLM),poplar pests population density were analyzed and the relationship between landscape pattern and its harm degree,to explore the influence law of landscape pattern in poplar pests.The main conclusions are as follows:(1)the proportion of forest land,cultivated land,grassland and wasteland in landscape in the erhe river valley is 7.5%,25.89%,16.76%and 39.84%respectively.The forest land in the river valley presents small patch distribution,and its maximum patch index,total edge length and average patch area are all smaller than other landscape types.Compared with 1988,the average patch area of woodland decreased from 0.047km2 to 0.007km2,and the average patch area of the landscape of river valley decreased from 0.034km2 to 0.0153km2,and the landscape of river valley showed serious fragmentation.(2)a total of 1225 cicadas were captured,including 29.06%,39.26%and 31.67%respectively.The leaf-eating rate of most plots ranged from 15%to 20%,with an average of 19%.The average population density was 1.3 head larvae/leaf.(3)the landscape scale,the landscape aggregation index and population density of three kinds of leaf pests was significantly positive correlation(r2=0.32,p=0.44),with the increase of mean patch fractal dimension,Yang(gyllenhal(p=0.04),and the leaf cicadas(p<0.01),the density of a significant rise,spring geometrid inhibition of density was significant(p=0.02),showed that different pests on landscape pattern of response.(4)of landscape fragmentation is the key to the poplar pests damage increase,but the feed rate of leaf and leaf moth population density of the response differences of the landscape pattern,landscape scale,the feed rate of leaf and landscape heterogeneity and landscape connectivity was significantly positively related to leaf moths harm and landscape heterogeneity has significant negative correlation,two kinds of damage of insect pests feeding range is different caused this difference;On the scale of landscape type,the more complex the patch shape of woodland and wasteland is,the more serious the damage of poplar to leaf pests in river valley is.The increase of cultivated land area leads to the increase of leaf moth population density.The response of two kinds of leaf pests to the characteristics of grassland landscape pattern is completely opposite.