Understanding the spatio-temporal changes of vegetation and its climatic control factors can provide an important theoretical basis for the protection and restoration of eco-environments.In this study,we analyzed the ...Understanding the spatio-temporal changes of vegetation and its climatic control factors can provide an important theoretical basis for the protection and restoration of eco-environments.In this study,we analyzed the normalized difference vegetation index(NDVI)in the Chinese Loess Plateau(CLP)from 2002 to 2018 via trend analysis,stability analysis,and Mann-Kendall mutation test to investigate the change of vegetation.In addition,we also used the skewness analysis and correlation analysis to explore the contribution of climate change and human activities on regional vegetation changes.The results indicated that the overall increasing trend of NDVI from 2002 to 2018 was significant The areas showing increased NDVI were mainly distributed in the south-eastern CLP and the irrigation districts of the Yellow River to the north and west of the CLP,while the areas showing decreased NDVl were concentrated in the desert of the westem Ordos Plateau,Longzhong Loess Plateau,and the built-up and adjacent areas.Precipitation was the dominant factor contributing to vegetation growth in the CLP,while vegetation was less dependent onprecipitation in the irigation districts.The increasement of NDVI has led to a prolonged responsetime of vegetation to water stress and a lag effect of less than two months in the CLP.The effect of temperature on NDVI was not significant;significant negative correlations between NDVI and temperature were found only in the desert,the Guanzhong Plain,the southem Liupan Mountains,and the southeastem Taihang Mountains,owing to high temperatures,urban heat islands,and large cloud cover in mountainous areas.Affected by the"Grain for Green Program"(GGP),NDVIin the CLP increased from 2002 to 2018;however,the increasing trends of NDNI for differentvegetation cover types were significantly different owing to the difference in background status.The increasing contribution rate of NDVI in the CLP mainly came from crops and steppes.Urban not only led to the destruction of vegetation but also had radiation effect causing negative impact of NDVI around the cities.This resulted in the aggravation of the negative bias of NDVI with time in the CLP.The results provide a long-term perspective for regional vegetation protection and utilization in the CLP.展开更多
基金supported by the Natural Science Foundation for Young Scientists of Shanxi Province of China(201801D221043)the Science and Technology Innovation Fund of Shanxi Agricultural University(2016YJ16,2017022).
文摘Understanding the spatio-temporal changes of vegetation and its climatic control factors can provide an important theoretical basis for the protection and restoration of eco-environments.In this study,we analyzed the normalized difference vegetation index(NDVI)in the Chinese Loess Plateau(CLP)from 2002 to 2018 via trend analysis,stability analysis,and Mann-Kendall mutation test to investigate the change of vegetation.In addition,we also used the skewness analysis and correlation analysis to explore the contribution of climate change and human activities on regional vegetation changes.The results indicated that the overall increasing trend of NDVI from 2002 to 2018 was significant The areas showing increased NDVI were mainly distributed in the south-eastern CLP and the irrigation districts of the Yellow River to the north and west of the CLP,while the areas showing decreased NDVl were concentrated in the desert of the westem Ordos Plateau,Longzhong Loess Plateau,and the built-up and adjacent areas.Precipitation was the dominant factor contributing to vegetation growth in the CLP,while vegetation was less dependent onprecipitation in the irigation districts.The increasement of NDVI has led to a prolonged responsetime of vegetation to water stress and a lag effect of less than two months in the CLP.The effect of temperature on NDVI was not significant;significant negative correlations between NDVI and temperature were found only in the desert,the Guanzhong Plain,the southem Liupan Mountains,and the southeastem Taihang Mountains,owing to high temperatures,urban heat islands,and large cloud cover in mountainous areas.Affected by the"Grain for Green Program"(GGP),NDVIin the CLP increased from 2002 to 2018;however,the increasing trends of NDNI for differentvegetation cover types were significantly different owing to the difference in background status.The increasing contribution rate of NDVI in the CLP mainly came from crops and steppes.Urban not only led to the destruction of vegetation but also had radiation effect causing negative impact of NDVI around the cities.This resulted in the aggravation of the negative bias of NDVI with time in the CLP.The results provide a long-term perspective for regional vegetation protection and utilization in the CLP.
