摘要
【目的】监测南水北调中线水源区2000—2015年森林空间分布格局,研究森林动态变化过程及其机制,为水源区森林生态系统保护和水质安全提供理论依据。【方法】基于2000、2010和2015年3期30 m分辨率国产环境灾害卫星HJ-1 A/B CCD以及Landsat TM影像数据,采用面向对象决策树分类方法,监测南水北调中线水源区的土地覆被,并运用像元二分模型和归一化植被指数估算植被覆盖度。【结果】3期土地覆被数据精度(K)分别为89. 4%、86. 9%和84. 4%,2000年用户精度为98%,2010年用户精度为96%,2015年用户精度为94%。土地覆被监测结果表明,受退耕还林和封山育林等生态工程项目实施影响,2000—2015年,南水北调中线水源区森林面积持续增加,增幅达9. 5%,增加面积主要来自草地、耕地和建设用地;然而,随着水源区大规模移民和区域经济不断发展,也使得约4 547 km^2的森林转化为耕地、草地和建设用地。分市统计分析表明,十堰市和安康市森林面积增量最大,均超过1 300 km^2,生态修复工程效果显著。2000—2015年,水源区植被覆盖度也呈增加趋势,其中森林植被覆盖度增幅达25. 4%,且植被覆盖度在0. 6以上的森林面积比例3期均超过70%。【结论】近15年来,南水北调中线水源区森林面积和森林植被覆盖度增加显著,森林密度得到提升,高密度的森林植被能够在地表形成植被保护层,降低水源区发生水力侵蚀和沟渠侵蚀的风险,从而提高水源区水土保持能力。
【Objective】 Monitoring the spatial distribution pattern of forest in the water source area of the middle-route of the south-to-north water diversion project from 2000 to 2015 and studying the process mechanism of forest dynamic change provide a theoretical basis for forest ecosystem protection and water quality safety in the study area.【Method】 Based on the 30 m resolution HJ-1 A/B CCD images(2010, 2015)and Landsat TM images(2000), the object-based decision tree classification method was used to obtain the land cover and the pixel dichotomy model for fractional vegetation coverage(FVC)estimation by NDVI.【Result】 The classification accuracy K value went up to 89.4%, 86.9% and 84.4%, respectively and the user’s accuracy of forest was 98% in 2000, 96% in 2010 and 94% in 2015.The result showed that the acreage of forest increased continually from 2000 to 2015, and mainly transferred from grassland, cropland and construction land, due to the implementation of ecological projects, such as Grain for Green.However, because of the mass migration and the continuous development of regional economy, part of the forest acreage turned to cropland, grassland and construction land.Due to the remarkable implementation of ecological projects, in the statistical analysis of cities, the increments of forest area in Shiyan city and Ankang city were the most, reaching 1383.9 km^2 and 1344.8 km^2 ,respectively.From 2000 to 2015, the FVC of forest increased with a rate of 25.4%.The acreage with FVC above 0.6 took account of the largest proportion of forest area.【Conclusion】 In summary, not only the acreage of forest, but also the FVC of forest both increased significantly.Thus the quality of forest in the water source area has been improved generally, which form the vegetation protective layer on the surface to reduce the risk of water erosion and ditch erosion, so as to improve the soil and water conservation capacity of the water source area.
作者
高文文
曾源
刘宇
衣海燕
吴炳方
鞠洪波
Gao Wenwen;Zeng Yuan;Liu Yu;Yi Haiyan;Wu Bingfang;Ju Hongbo(Research Institute of Forest Resource Information Techniques,CAF Beijing 100091;State Key Laboratory of Remote Sensing Science,Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences Beijing 100101;Research Institute of Geographic Sciences andNatural Resources, Chinese Academy of Sciences Beijing 100101)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2019年第4期97-107,共11页
Scientia Silvae Sinicae
基金
国家重点研发计划(2016YFC0500201)
国务院南水北调项目"利用遥感技术对南水北调中线水源区生态环境变化的监测研究"
国家自然科学基金项目(41671365
41771464
41501199)
关键词
森林
植被覆盖度
南水北调中线水源区
面向对象分类
forest
fractional vegetation cover
the middle-route of the south-to-north water diversion project
object-based classification
