Abstract: Many types of ecological construction measures have played an important role in the greening of China's land, but the contribution of grassland greening need a close attention to be paid. Taking Ningxia as an example, the study first time used the remote sensing data of more than 20 years and precipitation data of more than 40 years to evaluate the effect of the policy of grassland grazing constraint and conservation in Ningxia by Mann-Kendall nonparametric estimation method and NDVI residual trend analysis method. The results showed that:① From 2000 to 2022, Ningxia grassland NDVI showed a significant increase trend, with a cumulative increase of 69.92% for 23 years; ② The grassland vegetation restoration area accounts for 76.88% of the total grassland area, and the degradation area only for 0.27%; ③ Grassland contributes about 59% to Ningxia land greening, the largest contribution among all types of ecosystems; ④ After the implementation of the policy, the restoration of grassland vegetation in Ningxia showed a strong vitality, and the ability to cope with climate change and resist to drought stress is constantly enhanced; ⑤ Grassland vegetation restoration dominated by climate and policy factors accounted for 64.34%, along with that the policy factors for 33.94% alone, and by climate factors for only 1.72%, which demonstrated that policy factors had significantly promoted grassland vegetation restoration rather than the climate factors.

Key words: Grazing constraint and grassland conservation, Effectiveness evaluation, Remote sensing in a long time series, Vegetation restoration, Climate change

摘要： 为揭示草原对宁夏国土增绿贡献和草原植被恢复驱动因素，本研究首次结合近20余年遥感数据和40余年降水量数据，采用Mann-kendall非参数估计方法、植被指数残差趋势分析等方法对宁夏草原禁牧封育成效进行评估。结果表明：2000-2022年，宁夏草原NDVI呈显著增加趋势，23年累计增长幅度69.92%；草原植被恢复区域占草原总面积的76.88%，退化区域仅占草原总面积的0.27%；宁夏草原对国土增绿面积的贡献约59%，在各类生态系统中面积贡献比例最大；在禁牧封育政策实施后，宁夏草原植被恢复力强劲，应对气候变化能力不断增强；气候因素和政策因素共同主导的草原植被恢复面积占64.34%，政策因素主导的面积占33.94%，气候因素主导的面积仅占1.72%。表明禁牧封育的实施有效促进了草原植被生长，基本上遏制了草原退化，较气候因素更显著促进了草原植被恢复。

关键词: 禁牧封育, 成效评估, 长时间序列遥感, 植被恢复, 气候变化