State Key Laboratory of Grassland Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China.
Institute of Fragile Eco-Environment, Nantong University, Nantong, 226007, China.
Sci China Life Sci. 2023 Feb;66(2):385-405. doi: 10.1007/s11427-021-2143-3. Epub 2022 Aug 26.
Grasslands are the most dominant terrestrial ecosystem in China, but few national grassland maps have been generated. The grassland resource map produced in the 1980s is widely used as background data, but it has not been updated for almost 40 years. Therefore, a reliable map depicting the current spatial distribution of grasslands across the country is urgently needed. In this study, we evaluated the grassland consistency and accuracy of ten land cover datasets (GLC2000, GlobCover, CCI-LC, MCD12Q1, CLUD, GlobeLand30, GLC-FCS30, CGLS-LC100, CLCD, and FROM-GLC) for 2000, 2010, and 2020 based on extensive fieldwork. We concluded that the area of these ten grassland products ranges from 107.80×10 to 332.46×10 km, with CLCD and MCD12Q1 having the highest area consistency. The spatial and sample consistency is highest in the regions of east-central Inner Mongolia, the Qinghai-Tibet Plateau and northern Xinjiang, while the distribution of southern grasslands is scattered and differs considerably among the ten products. MCD12Q1 is significantly more accurate than the other nine products, with an overall accuracy (OA) reaching 77.51% and a kappa coefficient of 0.51; CLCD is slightly less accurate than MCD12Q1 (OA=73.02%, kappa coefficient=0.45) and is more conducive to the fine monitoring and management of grassland because of its 30-meter resolution. The highest accuracy of grassland was found in the Inner Mongolia-Ningxia region and Qinghai-Tibet Plateau, while the accuracy was worst in the southeastern region. In the future grassland mapping, cartographers should improve the accuracy of the grassland distribution in South China and regions where grassland is confused with forest, cropland and bare land. We specify the availability of valuable data in existing land cover datasets for China's grasslands and call for researchers and the government to actively produce a new generation of grassland maps.
草原是中国最主要的陆地生态系统，但全国性的草原图生成很少。20 世纪 80 年代制作的草原资源图被广泛用作背景数据，但近 40 年来一直没有更新。因此，迫切需要一幅可靠的全国性草原空间分布地图。本研究利用大量野外调查数据，评估了 10 个土地覆盖数据集（GLC2000、GlobCover、CCI-LC、MCD12Q1、CLUD、GlobeLand30、GLC-FCS30、CGLS-LC100、CLCD 和 FROM-GLC）在 2000、2010 和 2020 年的草原一致性和精度。结果表明，这 10 个草原产品的面积范围为 107.80×10 至 332.46×10 km，其中 CLCD 和 MCD12Q1 的面积一致性最高。在中东部内蒙古、青藏高原和北部新疆地区，空间和样本一致性最高，而南部草原的分布较为分散，在 10 个产品之间差异较大。MCD12Q1 的总体精度（OA）为 77.51%，kappa 系数为 0.51，明显高于其他 9 个产品；CLCD 的 OA 为 73.02%，kappa 系数为 0.45，略低于 MCD12Q1，由于其分辨率为 30 米，更有利于对草原的精细监测和管理。在内蒙古-宁夏地区和青藏高原，草原的精度最高，而在东南部地区，精度最差。在未来的草原制图中，制图员应提高中国南方和草原与森林、耕地和裸地混淆地区的草原分布精度。我们指明了现有土地覆盖数据集对中国草原的可用性，并呼吁研究人员和政府积极制作新一代的草原地图。
