Analysis Of The Spatio-temporal Evolution Of Ecosystem Services Based On GIS And RS

In order to find out the change characteristics and driving mechanism of ecosystem services in Yuanyang County,Yunnan Province,in this study,based on MODIS-NDVI data,Landsat data,meteorological,terrain,soil,geographic information and other parameters,simulated the different types of ecosystem services between 2005 and 2015in Yuanyang County used NPP,precipitation and soil erosion as time and space regulation factors.Taking into account the linkage and balance of the indicators,the total index synthesis of regional ecosystem services was established by means of transfer criterion and generalized mean calculation method,and analyzed its spatial and temporal variation trend.The results showed that:?1?The change of net primary productivity?NPP?of vegetation is an important index reflecting the change of service type of various ecosystem services.From 2005 to2015,the spatial distribution of NPP was significantly different in Yuanyang,increasing from the northeast to southwest,with an annual average of 380.57 g C·m^-2·a^-1.The vegetation NPP differed among land use types.The monthly and inter-annual NPP showed substantial variation.The uneven distribution of solar radiation had greater influence on NPP than that of precipitation during the year.The annual NPP presented a fluctuant increasing trend during the past decade.The overall annual NPP was increased slightly.With the implementation of returning farmland to forest and grassland,the area of cultivated region with NPP of 200–300 g C·m^-2·a^-1 was decreased,and that of the woodland and grassland with NPP of 300–400 g C·m^-2·a^-1 showed an increasing trend.The change trends of NPP in different areas of Yuanyang could be classified as significantly increased?P<0.01?,slightly increased?P<0.05?,and no significant change,of which 29.5%of the area increased significantly,and 16.3%of the area increased slightly.The trend of NPP increasing varied across different vegetation types.The proportions of areas with significantly increasing NPP were 58.1%for woodland,19.2%for grassland,17.4%for arable land,11.4%for construction land,and 8%for garden.The changes of NPP were influenced by natural factors and human factors.?2?Soil erosion can directly reflect the strength of regional water and soil conservation services.The spatial differentiation of soil erosion in Yuanyang County was remarkable.The soil erosion area was concentrated on the southeast and southwest,the erosion widely distributed among both sides of Tengtiao River.Extreme and violent erosion presented a point distribution trend.The average soil erosion modulus was11.06 t/?hm²·a?from 2005 to 2015,the erosion level was basically micro and mild which occupied 80 percent.Mild and moderate erosion contributed nearly 50 percent of total annual soil erosion,which was the key level of soil erosion control.Generally,the soil erosion had been slowed down with the improvement on forest cover in ten years.The terrain was complicated and changeable in Yuanyang County,so soil erosion distribution had a prominent correlation with altitude and slope.The formation of this distribution pattern was influenced by numerous natural and human factors.The key area of soil and water protective governance were below 500 meters,above 1500 meters and slope located at 25⁴5°.?3?The comprehensive calculation showed that,the single index of ecosystem service benefit of high top three in turn were food production,raw material production,aesthetic landscape services.In terms of spatial distribution,the overall distribution of ecosystem services was basically the same in Yuanyang County during 2005-2015,the high values were in the southern border,the northwestern border,the central southwestern and the border.The consistent distribution of ecosystem services indices over the years shows that the ecosystems in the region had shown a relatively steady state in the past decade.Specifically,the average value of ecosystem service index over the years were 0.008,0.009,0.008 respectively,the maximum values were 0.022,0.022,0.023.In terms of the trend of change,the distribution of global trend of ecosystem service index over the years was basically the same,with obvious concave trend in the east-west direction and weak deformation in the north-south direction.According to different types of land cover,the mean value of ecosystem service index of forestland was the highest,which can provide the highest benefit,followed by cultivated land,while the other types had no obvious difference.This study was applied to the quantitative assessment of ecosystem services in Yuanyang County by integrating various model methods.It can be a useful complement to the assessment system of regional ecosystem services.In addition,it provides reference and basis for rational land use,resource management and ecological environment construction.