Impact of tundra vegetation type on topsoil temperature in central Spitsbergen (Svalbard, High Arctic)

•Topsoil temperature was measured under different tundra vegetation types.•Tundra vegetation type significantly affects topsoil temperature.•Marsh and wet moss tundra vegetation were the warmest sites.•Arctic meadow and heath tundra vegetation were the coldest sites.•Freeze-thaw events in the soil were clearly less numerous than in the atmosphere. Current climatic models and projections forecast further increases in air temperature in the Arctic in the future. Therefore, new knowledge concerning the variability of air and soil temperature as well as its dependence on environmental factors is urgently needed to better understand and forecast the consequences of climate warming in the Arctic region. The main aims of this study were: 1) to determine the variability of the topsoil temperature for the one-year time scale under different types of tundra vegetation in the Adventdalen Valley in the central part of Spitsbergen (Svalbard, High Arctic), and 2) to determine the impact of different types of tundra vegetation on the topsoil temperature on a microscale in this area. The obtained results indicate that wet sites covered with marsh and moss tundra vegetation exhibited a significantly higher mean annual topsoil temperature (−0.7 °C and −1.2 °C, respectively) than sites featuring bare ground (−1.5 °C), Arctic meadow (−2.1 °C), and heath tundra vegetation (−2.4 °C). The mean topsoil temperature during the summer season was the lowest at sites covered with Arctic meadow and heath tundra vegetation (4.9 °C and 5.7 °C, respectively), and highest at the site with bare ground (6.9 °C). The topsoil temperature was highly and significantly correlated with the air temperature (correlation coefficient between 0.86 and 0.92); however, the correlation was clearly higher during the autumn and summer seasons (correlation coefficient between 0.76 and 0.89; p