Study On Land Use Change And Ecosystem Services Trade-off In Karst-coastal Zone Of Southwest Guangxi

The Land use/cover change has a close relationship with ecosystem services.The land use modeand intensity will affect the provision of various ecological process and ecosystem services.It is not only the science of sustainable development at home and abraod,but also the dynamic change law of land use chanage and ecosystem services and the relationship between the rights and balances and coordiantion among the services.The new direction of ecological and geography research is also the demand of the current ecological environment construction and sustainable development.It is of special theoretical and practical significance to choose karst-coastal zone in Southwest Guangxi to study the trade-off or coordination of land use changes and its ecosystem services.Taking karst-coastal zone in Southwest Guangxi as the research object,based on the land use change rate,dynamics degree and transfer matrix method,the land use change characteristics of the research area from 2005 to 2018 are analyzed;Based on the Invest model and scenario simulation method,the supply capacity of the four ecosystem services,including soil conservation,water production services,carbon storage and habitat quality,was evaluated,and the temporal and spatial trade-off or coordinaion relationship of ecosystem services were discussed.The main conclusions are as follows:(1)During the period of 2005-2018,the land use pattern of the study area has changed greatly,with the most obvious changes in construction land,cultivated land and land.With the rapid development of economic and social and the rapid expansion of urban and rural areas,the new constructions continue to occupy arable land,but the amount of arable land has not been supplemented,which makes the cultivated land area in the study area continueto decrease and the construction land area continue to increase,among which the cultivated land distributed in the river valley basin and basin Beibu Gulf coastal area is the most acutely converted into construction land.The increase of construction land mainly comes from the tansformation of cultivated land and woodland,and woodlands is the largest source of cultivated land increase.In the past 14 years,although the area of forest land has decreased,the area of forest land is still the largest,accounting for more than 60% of the total area.It is widely distributed in all areas of the study area,with the most concentrated in nature reserves,forest parks and forest management and protection areas.On the whole,the land use pattern and intensity show significant transitional characteristics.(2)From 2005 to 2018,the change characteristics of ecosystem services such as soil conservation,carbon storage,water production and habitat quality in the study area have similar regularities,and the spatial distribution pattern of various services has little changed.The high value areas of ecosystem services are mainly concentrated in nature reserves,forest parks,and forest management and protection areas,and the soil conservation,carbon storage and ecological envirment of forest land.Thesupply capacity of water production and habitat quality services was the largest.The low value areas are mainly distributed in the river valleys of Zuojiang Youjiang Yongjiang and the coastal zone of Beibu Gulf where human activities are frequent and cultivated land and construction land are concentrated.On the whole, the supply capacity of soil conservation,water yield,carbon storage and habitat quality services showed significant transitional characteristics,which was consistent with the transitional characteristics of land use pattern and intensity.(3)Based on the evaluation results of the four ecosystem services of the Invest model,the correlation analysis of various ecosystem services and the identification and division of important areas of integrated ecosystem services were carried out through the ArcGIS platform.The ecosystem services in the study area show positive spatial correlation and synergy,that is,the ecosystem services have the same changing trend.There are many types of ecosystem services.The high importance areas of integrated ecosystem services mostly occur in forest land types,mainly distributed in nature reserves,forest parks and forestry management and protection areas with less impact of human activities;In general,the ecosystem services are inclined to a certain type of ecosystem services,most of which are constryction land,cultivated land and other land types.(4)Based on the scenario simulation,the evolution of ecosystem services in the study area was simulate by using thr Invest model,which includes natural development priority,urban-rural expansion priority and ecological protection priority.The results show that the supply capacity of soil conservation,carbon storage,water production services and habitat quality service is reduced under the natural development priority scenario and urban-rural expansion priority scenario;Under the priority of ecological protection,the supply capacity of soil conservation,carbon storage,water production service and habitat quality service has been improved.If the main development goal is to provide ecosystem services with high quality and realize regional sustainable development,the priority scenario of ecological protection is more suitable for the development of the research area.Under different land use scenarios,there are still significant transitional characteristics in the saptial supply capacity of various services in the research area.