Ecological Benefits Of Land Use In The Loess Plateau Based On NPP And Ecological Green Equivalent

The ecological environment of the Loess Plateau area is fragile,and the former land use one sidedly pursues its social and economic benefits,but neglects the realization of the ecological benefits of land use.The ecological benefits of land use will affect the sustainable development of social economy in the Loess Plateau.Loess Plateau is the most concentrated area in the Loess Plateau in the world.The Loess Plateau has become one of the most serious areas of vegetation degradation and soil erosion in the world because of the erosive nature of the Loess and the strong human activities in history.The consequent ecoenvironmental degradation seriously hinders the social and economic development of the region.The purpose of this study is to analyze the change trend of the current vegetation NPP and its spatial pattern,and combine the green equivalent model to analyze the change trend of the ecological benefits of the Loess Plateau and provide support for the scientific and rational utilization of the land in the future.By analyzing the current situation of land use in the four phase of the Loess Plateau,the temporal and spatial distribution characteristics of land use change in the Loess Plateau were obtained.Then,based on the CASA model,using remote sensing and 3S means,combined with MODIS/NDVI data,meteorological data and land use data,the NPP data of the Loess Plateau for 2000-2015 years are estimated,and then the spatial and temporal analysis of the Loess Plateau NPP is carried out.The change trend of the ecological benefit of land use in the Loess Plateau was studied by comparing and analyzing the vegetation NPP and the land use change data of different land use types in different years of the Loess Plateau.Based on the ecological green equivalent model,the ecological service functions of different land use cover in the Loess Plateau were analyzed,and the ecological benefits of different types of land cover types in the 1990-2015 years of the Loess Plateau were studied.The following conclusions are obtained:In the Loess Plateau,the area of land use cover type changed obviously in 2000-2015years.The area of forest,grassland and settlement increased obviously.The area of shrubs,arable land,water and unused land showed a decreasing trend.The area of cultivated land decreased obviously,the average annual decrease was 7737km2,the area of shrub was the smallest,and the annual average decreased by 166km2.In the past 2000-2015 years,the interannual fluctuations of vegetation NPP on the Loess Plateau were larger,but the overall growth rate showed an increasing trend,with an average annual growth rate of 9 gC/(m~2·a).The change trend of vegetation NPP in the Loess Plateau Area in the past 2000-2015 years is consistent with the overall trend of land use change.It shows that the overall ecological environment of the Loess Plateau has been improved year by year,the crop yield has increased year by year,and the effects of shrubs and unused land are remarkable,and the land use ecology has been improved.The benefit is increasing.According to the ecological green equivalent simulation results,the ecological benefit of land use in the Loess Plateau area was increasing in 1990-2015 years,of which1990-2000 years of ecological benefit increased slowly,and the ecological benefits of land use increased obviously during the 2000-2015 years.Grassland has the most contribution to the ecological benefit of land use,followed by forest.Therefore,the land use of the Loess Plateau should strengthen the management and protection of natural and artificial forest grassland,and improve the ecological benefits of land use continuously.