内蒙古大兴安岭根河植被覆盖度动态变化及影响因素的分析

研究植被覆盖度（Fractional Vegetation Cover，FVC）动态变化，可增强了解森林群落的抵抗力和恢复力，为森林生态系统定量评价提供科学依据。基于像元二分模型、Landsat-5 TM（2006、2010）及高分一号（GF-1，2016）数据估算了3个时期的根河市FVC，引入变化率和动态度2个指标评价其动态变化情况，并且分析了多因素对该变化的影响。实验结果显示：中度以上等级占总面积80%以上，2016年低、较低、中度、较高、高等级FVC分别为1 645.02、1 655.97、3 536.59、5 556.87、7507.15 km²。采用0.2 m航空CCD影像进行植被/非植被点提取后，针对2016年的FVC估算结果进行交叉验证的精度为0.92。变化分析结果显示：除部分地区外（敖鲁古雅），2006~2016 年间FVC变化整体上呈增加态，尤其是高等级增加了1 668.78 km²。综合来看，根河市植被覆盖良好，多重因素共同影响其动态变化，局部FVC对火灾干扰的变化极为敏感，低海拔和平坡FVC明显降低，与人类生产生活密切相关。

Analysis of Dynamic Changes of Fractional Vegetation Coverage and Influencing Factors of the Genhe in the Great Khingan of Inner Mongolia

Study of dynamic changes of fractional vegetation cover(FVC) can strength our understanding the resistance and resilience of forest communities，and thus can provide a scientific basis for the quantitative evaluation of forest ecosystem.Based on dimidiate pixel model，and Landsat-5 TM in 2006 and 2010，and Chinese high resolution satellite data(Gaofen-1，GF-1) in 2016，this study estimated three temporal FVC in the Genhe，the city located at the Great Khingan of Inner Mongolia.The dynamic changes were quantitatively detected by using two factors，the change rate and dynamic index.The impacts of forest many factors on the changes were further analyzed.These three temporal FVC estimates showed that，the above middle level occupied more than 80% of the total study area.In 2016，the lowest，low，middle，high and highest grades of FVC estimates were 1 645.02，1 655.97，3 536.59，5 556.87，7 507.15 km²，respectively.The airborne CCD image with 0.2 m resolution was applied to extract the vegetation/non-vegetation points，and then was used to conduct the cross-validation against the estimates from GF-1 data in 2016.Satisfied result was obtained with accuracy of 92%.Except for some areas(i.e.，Aoluguya)，the overall FVC estimates showed an increase from 2006 to 2016，especially for the highest level which increased 1 668.78km².In general，the situation of FVC in the study area is good，and multiple factors affected the dynamic changes.Some regional FVCs were extremely sensitive to the natural disturbances，for example，forest fires.Some regional FVCs in the low-altitude and flat-slope areas were significantly reduced，which was closely related to anthropological disturbances.