1990~2015年东北地区草地变化遥感监测研究

基于1990年和2015年东北地区草地数据集，采用草地动态度模型、草地变化程度综合指数、草地相对变化率、质心模型和景观指数等作为参考指标对草地时空演变特征及其驱动因素进行分析.结果表明：25a间，东北地区草地面积减少了9755.94km²，其中，内蒙古自治区东部减少量最大；黑龙江省草地动态度、变化程度综合指数和相对变化率最高，分别为-30.67%、21.68%和5.55，草地变化最剧烈、稳定性最差；内蒙古自治区东部相应三个指标最低，分别为-3.76%、2.66%和0.68，年均变化强度最高，为0.0193%，相对其他省草地更稳定，但其减少规模最大；草地质心向西偏南方向移动11.28km，是由东部黑龙江省和西部内蒙古自治区东部草地动态强度巨大差异所致；东北地区草地破碎化程度降低、景观类型稳定性上升、斑块形状趋于规则化，主要是小斑块、破碎斑块转化为其他土地类型的结果.气候变暖、变干是草地退化的自然驱动因素，人口增加和经济增长间接影响了草地变化，牲畜大幅度增长是重要因素.

Remote sensing investigation of grassland change in Northeast China during 1990~2015

Northeast China is located in the eastern section of the agro-pastoral ecotone in the northern grassland. It is a typical ecologically fragile zone, sensitive to human disturbance and climate change. Based on the grassland datasets in Northeast China in 1990 and 2015, grassland dynamics model, grassland change degree comprehensive index, grassland relative change rate, area-weight centroid model and landscape index were used as reference indicators to analyze the Spatio-temporal dynamics and their driving factors of grasslands. The results showed that the grassland area in Northeast China decreased by 9,755.94km² during 1990 and 2015, among which the Eastern Inner Mongolia Autonomous Region had the largest reduction; the grassland dynamic degree, the change degree comprehensive index and the relative change rate of the Heilongjiang Province were the highest, namely -30.67%, 21.68% and 5.55, respectively, and the grassland had the most dramatic changes and the worst stability. The corresponding three indicators in the Eastern Inner Mongolia Autonomous Region were the lowest, namely -3.76%, 2.66% and 0.68, respectively, with the highest average annual change intensity of 0.0193%, which was more stable than other provinces, but its reduction was the largest. The grassland area-weight centroid moved 11.28km to the southwest in Northeast China, which was caused by the huge difference in grassland dynamic intensity between the Heilongjiang Province and the Eastern Inner Mongolia Autonomous Region. The fragmentation of grassland in Northeast China has decreased, the stability of landscape types has increased, and the shape of patches tended to be regular, mainly due to the conversion of small patches and fragmentized patches into other land-cover types. Climate warming and drying were the natural driving factors for grassland degradation. Increasing population and economic growth had indirectly affected grassland changes, and livestock growth was an important factor for grassland degradation.