Land Use Change And Its Comprehensive Ecological Effect Of Savannakhet In Lao PDR

With the increasingly profound and complex impacts of human on the earth's surface cover and ecosystem,land use/cover change(LUCC)and its environmental ecological effects have become a hotspot in global change and sustainable development.Many underdeveloped areas with good natural environments are experiencing a process of LUCC at the expense of eco-developed economies,where LUCC and environmental ecological effects are urgently needed to be properly assessed and valued.In this paper,the land use of 1975,1990,2005 and 2015 in Savannakhet of Laos was extracted from remote sensing data,and the land use structure and spatiotemporalevolution were quantified.This paper analyzes the characteristics of land use and thechange law,and expounds the comprehensive ecological effect of LUCC based on theanalysis of landscape ecological pattern and regional ecosystem service,so as toprovide scientific basis for local land use development,and then provide a scientific basis for the development of land use and land use to promote the sustainable development of resources and environment.The conclusions are:(1)The land use structure of Savannakhet is characterized by "high vegetation coverage,low construction intensity and rapid expansion of cultivated land",among which forest land>grassland>cultivated land>water>unused land>construction land(in 2015).The main pattern is " forest land-grassland-cultivated land "to the plains,while " forest land-grassland" mainly to the hill mountainous region;(2)The regional LUCC is not intense,while the degree of utilization is deepened from 1975 to 2015.The cultivated land and unused land are the most significant changes and keep the trend.The construction land and water increase slightly.The grassland is declining and the forest land is slightly reduced;(3)In the past 40 years,the overall pattern of land use was "forest land-grassland-cultivated land",which dominated the land use change in Savannakhet,among which unused land and other forest land and grassland are more in 1975?1990,the scale of land use change from 1990 to 2005 has been reduced,the scale of change from 2005 to 2015 has increased again,the grassland has been transferred out,the water body has increased significantly,cultivated land continue to expand;(4)In the past 40 years,the change of landscape pattern in Savannakhet showed the characteristics of "forest land-grassland control,cultivated land-water body expansion,increase of construction land and obvious degradation of unused land".In the landscape pattern of forest land,cultivated land and water continue to erode the dominant landscape.The landscape heterogeneity is enhanced,and the fragmentation is more uniform,when the stability of the pattern is decreased but the overall characteristics remain unchanged.(5)In the past 40 years,the total value of ecosystem service(ESV)in Savannakhet has increased to 5.62 × 109 $,the forest value is the largest and the proportion is over 80%.Secondly,the value of grassland is obviously decreased,the value of cultivated land and water is similar and obviously increased.And unused land value is the smallest and continues to decline.The overall ecosystem service function is mainly natural adjustment and support services,the supply service is growing rapidly,and the intervention of human activities is low.