宁夏草地绿度时空变化图谱及驱动因素分析OA北大核心CSTPCD

[Objective]The aims of this study are to reveal the spatial and temporal variations pattern of grass-land greening in Ningxia and proveits driving factors,and provide decision-making reference for effectively managing the grassland carbon reservoir in the ecologically fragile areas of agriculture and animal husbandry in northern China and promoting the long-term ecological increase of grassland in Ningxia.[Methods]Based on NDVI,meteorological and land use data,geographical information map,Sen+Mann-Kendall trend analysis,coefficient of variation,Hurst index,partial correlation analysis,residual analysis methods were adopted.The spatial and temporal distribution and variation characteristics of grassland greenness in Ningxia from 2000 to 2020 were analyzed.The driving mechanism of climate change and human activities on grassland greenness was explored.[Results]The greenness of grassland in Ningxia fluctuated at the rate of 0.007/a,the greenness of meadow grassland was the highest and the fastest growth rate was 0.011/a,and the green-ness of desert grassland was the lowest and the slowest growth rate was 0.004/a.The average monthly varia-tion of grassland greenness in Ningxia showed an inverted U-shape,and the maximum greenness of different types of grassland varied greatly,and the minimum value was similar.The spatial difference of grassland greenness in Ningxia was obvious,showing a pattern of high level in the south and the low level in the north.The greenness increased from south to north from March to August,and gradually decreased from north to south from September to February.97.76% of the greenness of grassland showed an increasing trend,with the largest proportion of extremely significant increase being 48.78%,the greenness of desert grassland and typical grassland changed to high fluctuation and the greening trend was not continuous,and the greenness of meadow grassland changed to medium and low fluctuation and the greening trend was sustainable.Ningxia grassland greenness and temperature were positively correlated with precipitation,and 67.10% of the area was mainly driven by precipitation.The residual analysis showed that human activities mainly had a positive effect on the greenness of grassland in Ningxia,and ecological projects such as returning farmland to grass-land promoted the greenness of grassland,and the expansion of construction land led to the reduction of grassland greenness.[Conclusion]Since 2000,the grassland greening of Ningxia has improved significantly,and the increase in southern Ningxia is particularly significant.Desert grassland and typical grassland fluctuate greatly,which needs to reduce the disturbance of human activities in the later management.