Impacts Of Wind Farm On Vegetation Phenology Of Different Types Grassland

Grassland has irreplaceable natural ecological significance and social economic value.Due to reasons such as cheap land and abundant wind energy,a large number of wind farms around the world are built on grasslands.However,existing research has shown that wind farms can have many impacts on environmental factors.And changes in the environment will inevitably affect the phenology of grassland vegetation.The impact of wind farms on the phenology of other types of grasslands worldwide is currently unclear.Therefore,this article selects 4 types of grassland with wind farm distribution worldwide as study areas to determine the impact of wind farms on the phenology of different types of grasslands.Firstly,MODIS data is used to calculate the daily vegetation index data of the study area,and new interpolation method and Whittaker smoothing method are used to remove a large number of outlier in the daily vegetation index data,so as to obtain high-quality daily vegetation index data.Then,the dynamic threshold method was used to extract grassland phenological information from high-quality daily data for four study areas.Moreover,by calculating the phenological difference between wind farms after construction and before,in turn comparing that difference between different zones of each study area,the impact of wind farms on the phenology of the four different grasslands mentioned above was analyzed.Finally,the reasons for the impact of wind farms on phenology were explored using precipitation and land surface temperature data combined with Pearson correlation analysis and one-way ANOVA methods;The impact of phenological changes on grassland productivity was analyzed by comparing the difference in net primary productivity(NPP)between wind farms after construction and before;The impact of phenological changes on grassland soil moisture was discussed using various climate data.The research results of this article show that:Wind farms can extend the phenological period of grasslands.The growth season of typical grasslands is extended by 3 ～ 5 days under the operation of wind turbines,and the peak season is extended by 3 ～ 4 days;The growth season of desert grasslands is extended by 4 ～ 5 days;The growth season of the meadow grassland is most significantly prolonged,about 4 ～ 7 days;The phenology of shrub grasslands will not be affected by wind farms,which may be related to the relatively stable phenology of shrubs.The reasons why wind farms can affect the phenology are different in each grassland.The extended growth season of typical grasslands due to wind farms is significantly correlated with the surface temperature in the first two months of the growth season,while the extended peak season is significantly correlated with the precipitation and temperature in the two months before its end;The extension of the desert grassland growth season is related to the surface temperature in the first two months before its onset;The extension of the growth season in the meadow grassland is significantly correlated with the precipitation in the two months before its end.The impact of phenological changes on NPP varies among different types grasslands.Prolonging the phenological period of typical grasslands can increase vegetation NPP;Prolonging the phenological period of desert grasslands will lead to a decrease in vegetation NPP,which may be related to water scarcity in desert grassland areas;The extension of the phenological period of the meadow grassland has no significant impact on its vegetation NPP,which may be related to the relatively sufficient regional water.The soil moisture of grasslands affected by phenology decreases due to the extension of phenological period.After the phenological period of typical grasslands,desert grasslands,and meadow grasslands is extended,the transpiration of vegetation increases.Among them,the vegetation transpiration of typical grasslands and meadow grasslands shows a significant increase,indicating that the extension of phenological period consumes more soil moisture,thereby reducing regional soil moisture.