| Monochamus alternatus is the main vector insect of Bursaphelenchus xylophilus,a quarantine disease in the world.Long-lasting and effective control of this species is very important to control the disease.However,there are no effective measures against this insect at present.Landscape pattern is an important factor affecting the number and dynamics of species population,and it can promote and inhibit the movement of species in heterogeneous landscape.In addition,extensive studies have proved that landscape pattern is closely related to the occurrence and spread of forest pests and diseases.However,little is known about the impact of landscape pattern on the population of long-horned beetles.In order to clarify the impact of landscape pattern on the occurrence of population,Xiapu County,in Fujian Province was selected as the study area,and the occurrence of population at each spot was investigated based on traps.At the same time,in order to determine the influence range and effect of each landscape type more accurately,the radius ranges of four different scales were set with each sample point as the center,and the landscape scale with the biggest influence of each landscape type was screened out by using the generalized linear mixed model,and the influence of landscape type on population occurrence was analyzed on the determined landscape scale.Then,in order to reveal the influence of landscape pattern on the temporal dynamics of population,this study uses the monitored population situation to construct the temporal dynamics model of population,and then calculates the time period of each period based on this model,and analyzes the relationship between landscape index and temporal dynamics of population at different levels through RDA.The research results are as follows:Firstly,the influence range of each landscape type was screened by the generalized linear mixed model,and it was found that the maximum influence radius of each landscape type on the occurrence of population was different.The maximum influence radius of forest,road,water and farmland land landscape area is 2000 m,and the urban landscape is 1000 m.In the analysis of the ratio of perimeter/area index of landscape types,it shows that the maximum influence radius of perimeter/area ratio of water and urban landscape is 2000 m,while the maximum influence radius of perimeter/area ratio of woodland,road and cultivated land landscape is 500 m,1500 m and 1000 m respectively.At the same time,the landscape pattern was studied based on the screened radius range.The results showed that the area and perimeter/area ratio of forest and road landscape were positively correlated with the occurrence of population,while the area and perimeter/area ratio of urban,water and the perimeter/area of cultivated land landscape were negatively correlated with its occurrence.The results of this study prove that different landscape types in the landscape pattern can have a significant impact on the population occurrence of Monochamus alternatus,and of this impact,forest and road landscape mainly play a role in strengthening the occurrence of this pest,while water,urban and farmland land show an inhibitory effect.Secondly,in order to further determine the role of landscape,the influence of landscape pattern on the temporal dynamics of population was explored.The results showed that there were differences in the occurrence time of long-horned beetles in different regions,and RDA model analysis showed that each landscape type had a significant impact on the population time dynamics.The area and aggregation of forest were positively correlated with the population time dynamics,and the density and number of road landscape were also positively correlated with it.The aggregation,perimeter/area ratio of water,area and density of urban and farmland were negatively correlated with population time dynamics.At the same time,the degree of landscape fragmentation was negatively correlated with the occurrence time of this species.To sum up,it can be found that forest and road landscape were the main reasons for the long occurrence period of Monochamus alternatus,while the distribution of water,urban and farmland shortens the occurrence time of population to a certain extent.This study not only preliminarily explored the action mechanism of landscape pattern on the population of this specie,but also proved that the ecological prevention and control of Monochamus alternatus can be realized by fully considering the stand structure and artificial landscape planning. |
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