Risk Assessment And Prediction Of Dendrolimus Spp.damage In Northeast China Based On MaxEnt Model

Forests are an important part of terrestrial ecosystems.Forests in a healthy condition are extremely important for the conservation of forest resources by providing biological resources,water conservation,climate regulation and carbon dioxide reserves.But forest pests and diseases are serious threats to the world’s forestry industry,and the Dendrolimus spp.is the most serious forest pest in the country,causing widespread infestation of forests.Therefore,the research on the occurrence mechanism and risk assessment of Dendrolimus spp.damage will be very important for pest control and forest resource protection.The mechanism of Dendrolimus spp.damage and its simulation and prediction have been the focus of research.The outbreak of Dendrolimus spp.damage is not the result of a single factor,but a combination of multiple environmental factors.However,the current research is faced with the problem of incomplete consideration of environmental factors,and the lack of geographical and temporal analysis and future prediction of the potential occurrence area of Dendrolimus spp.damage.Therefore,the research focus of this paper is to analyze the habitat conditions of Dendrolimus spp.damage and to simulate the prediction and risk assessment of potential Dendrolimus spp.damage areas.This paper selects the northeastern region as the study area and takes the distribution point data of Dendrolimus spp.as the basis.Using the environmental factors extracted from the remote sensing data,we analyze the main environmental factors affecting the occurrence of Dendrolimus spp.and the simulation prediction of the occurrence area by combining the distribution point data with the environmental factors data through MaxEnt model method.The main research contents and results of this paper are as follows.(1)The data of Dendrolimus spp.distribution points were collected,and environmental factors such as climate,topography,forest stand,soil,anthropogenic,and snowpack were considered comprehensively,and environmental factors were screened by using the contribution rate of jackknife method and correlation analysis.The response curves of environmental factors by multi-value extraction to point statistics and MaxEnt model were used to explore the main influencing factors of pine woolly adelgid infestation and the mechanism of disaster formation.The results show that climate factor is the main environmental factor affecting the occurrence of Dendrolimus spp.damage,followed by topographic factor and vegetation type,and that the areas with long sunshine hours,high temperature,low precipitation,high average annual temperature,medium altitude,gentle slope,and larch forest in Northeast China are favorable for the survival of Dendrolimus spp.(2)The habitat suitability results obtained from the MaxEnt model were graded by using the natural interruption point grading method.The risk level of Dendrolimus spp.damage was divided into non-infestation area,low-risk infestation area,medium-risk infestation area and high-risk infestation area,and the risk assessment of Dendrolimus spp.damage area in northeast China was carried out.The Dendrolimus spp.damage in northeast China is mainly concentrated in the Daxinganling area in eastern Inner Mongolia,Changbai Mountain area in Jilin Province,and Nurulhu Mountain area in Liaoning Province.The low-risk pest areas in the Daxinganling are scattered and extensive,the high-risk pest areas in the Changbai Mountain are concentrated and relatively large,and all risk areas in the Nurulhu Mountain are scattered overall.(3)The potential occurrence areas of Dendrolimus spp.damage in the future period under different climate scenario models were predicted,and the area of various types of risk infestation areas were counted and analyzed for changes.The results were obtained that the area of various types of risk infestation zones in most regions in Northeast China gradually increased from low to high under SSP126,SSP245 and SSP585 climate scenarios,with the largest area of infestation zones during 2081-2100.As time goes on,there is a tendency to expand the distribution of various types of risky pest areas,with the most drastic changes under the SSP585 scenario.So the climate conditions under SSP585 scenario are most suitable for the survival of Dendrolimus spp.,and the warming temperature will lead to the expansion of the potential infestation area in the future.Therefore,measures can be taken in the future to prevent a large outbreak of Dendrolimus spp.infestation by regulating climatic conditions and reduce the risk of pest threat to forest resources.