Response Of Photosynthetic Vegetation Coverage To Climate Change In Inner Mongolia Grassland

Vegetation is an important component of the earth's terrestrial ecosystem and is extremely sensitive to climate change.Vegetation coverage can well reflect the growth trend of vegetation communities on the surface and has a good indication for regional ecological environment changes.In recent years,Inner Mongolia has become one of the sensitive regions of global climate change due to the accelerated urbanization process,the increased development of natural resources and the increasingly fragile ecological environment.Understanding the response process of vegetation cover to climate in this region is helpful for rational development and utilization of resources,and is of great significance for maintaining sustainable ecological environment.Based on MODIS(MCD43A4,MOD09A1)global photosynthetic vegetation(PV)data products and major climate factor data from 2002 to 2016,this paper selects representative sample areas of grasslands,analyzes the annual,seasonal and monthly vegetation coverage and climate changes of different types of grasslands in Inner Mongolia,discusses the response process and characteristics of vegetation coverage to climate at different time scales,enriches the related research work on vegetation and climate in grassland areas of Inner Mongolia,and provides basic information for ecological environment construction in this area.The main conclusions are as follows:1.From 2002 to 2016,the multi-year average temperatures of meadow grassland,typical grassland and desert grassland in Inner Mongolia were-0.4?,2.3? and 3.2?,respectively.The annual average precipitation in the three grassland areas were 341.0 mm,299.7 mm and 295.4 mm respectively,and the annual variation of precipitation showed no significant fluctuation and rising trend.In the growing season of Inner Mongolia grassland,the average vegetation coverage for many years were 46.5% in meadow grassland,36.3% in typical grassland and 22.4% in desert grassland.The vegetation coverage of meadow steppe and typical steppe showed a non-significant growth trend with interannual variation,while that of desert steppe showed a non-significant decline trend.2.The monthly vegetation coverage of Inner Mongolia grassland has little correlation with the temperature of the current month and earlier period,which are mostly negative correlation,but there is a trend that the drier the grassland is,the greater the inhibition effect of the earlier period temperature on the vegetation;the spring(March to May)temperature has a certain promotion effect on the grassland vegetation of Inner Mongolia,but it is not significant;the monthly temperature and the average temperature in the growth season(Juneto September)have a inhibition effect on the vegetation In addition,the inhibition of annual average temperature on desert steppe was greater than that on typical steppe and meadow steppe.3.The monthly vegetation coverage of Inner Mongolia grassland has obvious 1-2month lag effect and significant cumulative effect on the monthly precipitation,and the more arid the grassland type lag effect is,the more obvious the characteristics;compared with meadow grassland and typical grassland,desert grassland vegetation is more sensitive to the precipitation change.4.The precipitation in winter can promote the vegetation growth of meadow grassland and typical grassland with not significant effect,but it can promote the vegetation coverage of arid desert grassland significantly;the response of annual vegetation coverage of three types of steppe to precipitation shows that the vegetation coverage are significantly affected by annual precipitation,precipitation in growing season and precipitation in June,July and August in annual,seasonal and monthly scales respectively.The linear fitting results of annual vegetation coverage and precipitation of the three types of grasslands in Inner Mongolia are all good.