Research On Spatial Pattern Optimization Of Ecosystem Services Based On Bayesian Network And Land Multi-scenario Simulation In Qinhuangdao City

With the rapid development of society and economy,human’s demand for natural resources expands rapidly and the intensity of utilization of natural resources increases continuously,which leads to the deterioration of regional ecological environment and the weakening of ecosystem service capacity.Therefore,on the regional scale,we should vigorously carry out the dynamic evaluation of land use change and ecosystem service level,explore the interaction between land use structure and ecosystem service,and analyze the spatial pattern of ecosystem service under different land use scenarios.These studies are of great significance for the in-depth analysis of the land use pattern suitable for regional ecological protection and construction.This paper takes Qinhuangdao,a typical coastal ecotourism city,as an example.We quantitatively estimated the water conservation services,soil conservation services,carbon sequestration services and biodiversity conservation services within the region,analyzed the mechanisms by which climate factors,topographic factors and socio-economic factors affect ecosystem services,and constructed a Bayesian network model for ecosystem services.Set different scene model to simulate the land use situation in 2030,introducing the uncertainty of land use into the Bayesian networks,predict four scenarios of ecosystem service spatial distribution pattern and compared with the current situation in order to select the optimal scenario of ecosystem services and define the key optimization areas,as the study area ecosystem services provide reference space structure optimization strategy,at the same time,it can also provide scientific reference for ecological protection and construction in other areas.The main conclusions of this paper are as follows:(1)There were significant differences in the spatial distribution of ecosystem service levels in Qinhuangdao.The service level of water conservation is mostly medium and high,and the high value area is mainly distributed in the river system.Soil conservation services were generally poor,and the low value area was mainly distributed in Changli County.The area with high value of carbon sequestration services mainly distributed in the north of the study area.The spatial distribution of biodiversity conservation services is highly similar to that of land use.The comprehensive level of ecosystem services is relatively high,and the area of high value area and second high value area accounts for 50.83%of the total area of Qinhuangdao.The Bayesian network model of ecosystem services constructed by coupling the ecosystem service model with the Bayesian network is verified with an error rate of 16.40%,which indicates that the model has good performance in predicting results and can accurately predict the level of ecosystem services under different situations.(2)Based on Logistic Ca-Markov model,the classification transformation rules were determined by logistic regression method.On this basis,the study set up the habitat mask rule and the habitat transformation rule,set up four scenarios of natural growth,ecological protection,ecological agriculture and ecological construction,and predicted the spatial distribution pattern of land use in Qinhuangdao in 2030.The simulation results showed that under the ecological protection scenario,the forest area increased the most,the expansion of construction land area was effectively restrained,and the comprehensive ability of ecosystem services was the strongest.Scenario-setting and land-type conversion rules can provide reference for the zoning management of land use and the optimization of ecosystem service pattern in Qinhuangdao City in the future.(3)Ecosystem services integrated index factors from high to low in turn for land use,gross national product and slope.Based on the sensitivity analysis results of Bayesian network and the simulation results of land use scenarios,Qinhuangdao city can be divided into 8 types of ecosystem service optimization units and 4 types of ecosystem service optimal zones:core ecological protection zone,ecological buffer protection zone,ecological agriculture development zone and construction control development zone.Implementing different development modes in different regions is beneficial to improving the comprehensive benefits of ecosystem services.This study can provide reference for the ecological management and conservation work of Qinhuangdao City,provide technical support for the formulation of land use planning and the construction of ecological protection projects,and also provide reference for the optimization of the spatial pattern of land use and ecosystem services in other regions.