Research On The Improvement Of Ecosystem Services In The Southern Hilly And Mountainous Barrier Zone Based On Spatial Optimization

Recent years have witnessed the acceleration of urbanization in many countries and regions.Land use and development activities have become more frequent and human activities are affecting the ecosystems from multiple perspectives.Due to the disturbance of human activities and the impact of climate change,the structure and processes of ecosystems have undergone tremendous changes.Not only the phenomenon of damage to ecosystems is very common,but also some ecological and environmental problems are becoming more prominent.In order to explore regional ecosystem spatial patterns that can effectively balance the contradictory relationship between economic development and ecological protection,scientists at home and abroad have carried out plenty of studies on evaluations around ecosystem services,dynamic simulation of land use,and the construction of regional landscape ecological security patterns.However,there is still lacks in optimizing the spatial pattern of regional ecosystems to improve ecosystem services,especially in the areas with fragile ecosystems,sharp conflicts between human activities and ecosystem protection,and prominent eco-environmental problems.Additionally,more attention is paid to local management strategies,the existing information summary,and some supplementary suggestions to the improvement of ecosystem services.There are relatively few quantitative studies based on the structure and dynamics of the ecosystem itself.In this study,we selected southern hills and mountains barrier region,one of"Two Screens and Three Belts”divided by The strategy of Major Functional Zone as the study area.It aims to take the perspective of multi-level regional ecosystem service improvement.First,with the help of ArcGIS10.5 and other software technologies,we utilized the secondary Land use/cover classification data to analyze the spatial and temporal dynamic characteristics of land use.Then,on the basis of above research,we used CASA model and other reliable tools to carry out three regulating service evaluation.Finally,based on the research of land use dynamic simulation and integrated with the basic theory of landscape ecology,we applied GeoSOS-FLUS model and Lingo software to carry out study on the improvement of three regulating ecosystem services under three different scenarios(background development scenario,coordinated development scenario and ecological priority scenario)to optimize the spatial pattern.A regional ecological security pattern can be built through a comprehensive quantitative study to explore the specific scenario setting and optimization plan of regional ecosystem service improvement.It can effectively balance the contradiction between economic development and ecosystem protection.Besides,it provides a practical and feasible scientific basis for land use planning,and also provides theoretical and technical support for the promotion of national ecological civilization construction strategy implementation in study area.The main research conclusions are as follows:(1)The ecosystem type of the southern hilly and mountain barrier region is dominated by forest,followed farmland;from the perspective of secondary classification,there are more evergreen broad-leaved forests in the region,accounting for the 45%of the total area,followed by evergreen coniferous forests,accounting for more than 15%of the total area of the southern hilly and mountain barrier region.The area of evergreen broad-leaved forest and deciduous coniferous forest is relatively large.From 1995 to 2015,towns and construction land in the region expanded rapidly.From 1995 to 2015,the changes in the area of various ecosystem types in the southern hilly and mountain barrier region have obvious phase characteristics,which can be divided into two phases:1995-2000 and 2000-2015:In the first stage(1995-2000),the forest ecosystem is degraded,which is related to the blind expansion of cultivated land and urban areas in the central and western regions.In the second stage(2000-2015),as the policy of Grain for Green Program in the central and western regions gradually deepened,the forest ecosystem in the study area gained recovery to some extent.The negative impact of human activities also weakened.(2)From 1995 to 2015,the three regulating ecosystem services in the southern hilly and mountainous barrier region decreased at first but then increased.The ability of providing services by ecosystems also showed the same trend.These are related to changes in regional precipitation and temperature,both of which are the main driving factors for changes in regional regulating ecosystem services.In addition,indirect driving factors such as population growth and rapid economic development are related to the decline in the quantity of ecosystem services from 1995 to 2000.(3)The spatial distribution of ecosystem types in the southern hilly and mountainous barrier region has vertical zonality,latitude zonality and longitude zonality.The temperature rise and the precipitation increase lead to the forest line rise and the forest layer expansion.The suitable area of the main ecosystem type(evergreen broad-leaved forest)in the region expanded north,west,and upward,and the suitable area increased.(4)Under three different simulation scenarios,the regulating ecosystem service equivalent EST of the ecological priority scenario,the total water conservation service equivalent of the study area ES1,the total soil retention service equivalentES2 and the total carbon sequestration service equivalent ES3 showed a significant improvement.It is due to the large increase in the area of forest ecosystems under planning;regulating ecosystem service equivalent EST under the coordinated development scenario,total water conservation service equivalent in the study area ES1,total soil retention service equivalent ES2 and the total carbon sequestration service equivalent ES3 have increased,which is related to the increase in the area of natural ecosystems under planning.In the background development scenario,the regional ecosystem service equivalent EST,the total water conservation service equivalent of the study area ES1,the total soil retention service equivalent ES2 and the total carbon sequestration service equivalent ES3 all have no significant improvement.The reason is that the background scenario is affected by changes in natural conditions,which has a slow effect on the spatial distribution and area changes of the ecosystem.