Internal response of vegetation growth to degrees of permafrost degradation in Northeast China from 2001 to 2020

• Published in: Geo-spatial Information Science
• Main Authors: Hong Yang, Yanqiu Xing, Xiaoqing Chang, Jiaqi Wang, Yuanxin Li, Jie Tang, Dejun Wang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2024
• Subjects: Permafrost degradation; vegetation growth; Net Primary Productivity (NPP); Northeast China (NEC); internal response; Mathematical geography. Cartography; GA1-1776; Geodesy; QB275-343; permafrost
• Online Access: https://doi.org/10.1080/10095020.2024.2363618; https://doaj.org/article/f20a68e6b2404012b273079b167d7950

Ecosystems at the southern edge of the permafrost distribution are highly sensitive to global warming. Changes in soil freeze-thaw cycles can influence vegetation growth in permafrost regions. Extant studies mainly focused on analyzing the differences of vegetation dynamics in different permafrost regions. However, the intrinsic drivers of permafrost degradation on vegetation growth remain elusive yet. Based on the top temperature of permafrost (TTOP) model, we simulated the spatial distribution of permafrost in Northeast China (NEC) from 2001 to 2020. Using the data of the vegetation Net Primary Productivity (NPP), vegetation phenology, climate and permafrost phenology, and analytical methods including partial correlation, multiple linear regression, and path analysis, we explored the response of vegetation growth and phenology to soil freeze-thaw changes and climate change under different degrees of permafrost degradation. Overall, the start date of the growing season (SOS) was very sensitive to the start date of soil thaw (SOT) changes, and multiple regression analyses showed that SOT was the main factor influencing SOS in 41.8% of the NEC region. Climatic factors remain the main factors affecting vegetation NPP in NEC, and the results of partial correlation analysis showed that only 9.7% of the regional duration of soil thaw (DOT) had a strong correlation with vegetation NPP. Therefore, we determined the mechanism responsible for the soil freeze-thaw changes and vegetation growth relationship using the path analysis. The results indicated that there is a potential inhibitory effect of persistent permafrost degradation on vegetation growth. Our findings would contribute to the improvement of process-based models of forest dynamics in the boreal region, which would help to plan sustainable development and conservation strategies in permafrost areas.