Effects of Surface Characteristics on the Existence of Isolated Permafrost in Northeastern Mongolia

Isolated patches of permafrost, where ground thermal changes are affected by ecosystem factors such as vegetation cover rather than climate, may be vulnerable to environmental disturbances in semiarid regions. However, the impacts of ecosystem factors remain underevaluated in Mongolia. This study monitored changes in the ground surface temperature with respect to vegetation biomass and snow thickness and characterized the ground temperature dynamics at five boreholes in a wetland. Dense vegetation at the permafrost sites cooled the ground surface, resulting in a smaller positive surface offset (SO). Conversely, sparse and dry vegetation warmed the ground surface, leading to a larger positive SO. At the permafrost sites, the negative thermal offset was greater than that at the permafrost‐free sites because of the latent heat flux in the water‐saturated soil beneath the peat layer. The permafrost‐free sites had shorter zero curtains with mineral soils compared with wetter soils underlain by isolated permafrost. Ecosystem‐driven permafrost formed in the semiarid region impeded water penetration, increasing soil moisture and fostering peat soil development due to a slower decomposition rate. These processes reduced ground temperatures. These processes were associated with vegetation–soil negative feedback, ultimately enhancing the resilience of isolated patches of permafrost to climate change.