46-Year (1973–2019) Permafrost Landscape Changes in the Hola Basin, Northeast China Using Machine Learning and Object-Oriented Classification

• Main Authors: Raul-David Șerban, Mihaela Șerban, Ruixia He, Huijun Jin, Yan Li, Xinyu Li, Xinbin Wang, Guoyu Li
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Remote Sensing
• Subjects: land use and cover changes (LUCC); object-based image analysis (OBIA); Support Vector Machine (SVM); permafrost; Northeast China
• Online Access: https://www.mdpi.com/2072-4292/13/10/1910

Land use and cover changes (LUCC) in permafrost regions have significant consequences on ecology, engineered systems, and the environment. Obtaining more details about LUCC is crucial for sustainable development, land conservation, and environment management. The Hola Basin (957 km²) in the northernmost part of Northeast China, a boreal forest landscape underlain by discontinuous, sporadic, and isolated permafrost, was selected for the case study. The LUCC was analyzed using the Landsat archive of satellite images from 1973 to 2019. A thematic change detection analysis was performed by combining the object-based image analysis (OBIA) and the Support Vector Machine (SVM) algorithm. Four types of LUCC (forest, grass, water, and anthropic) were extracted with an overall accuracy of 80% for 1973 and >90% for 1986, 2000, and 2019. Forest, the dominant class (750 km² in 1973), declined by 88 km² (11.8%) from 1973 to 1986 but had a recovery of 78 km² (12.5%) from 2000 to 2019. Grass, the second-largest class (187 km² in 1973), increased by 86 km² (46.5%) between 1973 and 1986 and decreased by 90 km² (40%) between 2000 and 2019. The anthropic class continuously increased from 10 km² (1973) to 37 km² (2019). Major features in LUCC are attributed to rapid population growth, resource exploitation, agriculture intensification, economic development, and frequent forest fires. Under a pronounced climate warming, these drivers have been accelerating the degradation of permafrost, subsequently triggering natural hazards and deteriorating the ecological environment. This study represents a benchmark for sustainable LUCC management in the Hola Basin, Northeast China.