Assessing climatic indicators of mire resilience along a subarctic-temperate gradient in the face of abrupt climate change: A study of selected Norwegian and Polish peatlands

Although the leading cause of peatland loss and deterioration is direct human activity, peatlands outside the influence of human activity are also subject to pressures that cause their transformation, evolution, and degradation. Due to the diverse course of accelerating climate change (increases in air temperature, changes in precipitation) and its consequences (changes in groundwater recharge, changes in water balance) across Europe, peatlands of different hydromorphological types at different latitudes respond differently to pressures resulting from climate change. In this study, we analyzed climatic indicators determining the resilience of five different types of natural peatlands representing four European mire regions: the palsa mire region (Šuoššjávri), the northern fen region (Øvre Forra), the typical raised bog region (Midtfjellmåsan), and the continental fen and bog region (Rospuda Valley and Biebrza Valley), along a gradient from subarctic Scandinavia to the temperate climate of Central Europe. We analyzed the variability of six characteristic indicators of meteorological conditions that affect the status of these peatlands over possibly long periods (from 1946 to 2022), namely annual sums and seasonality of precipitation, air temperature, evapotranspiration, water balance, and the length of rain-free periods. We revealed that the variability of these indicators was negative, implying an increased risk of losing or changing the character of these peatlands. The most significant changes were diagnosed for the Šuoššjávri palsa mire in northern Norway. The lowest risk of losing or changing the character of peatlands due to climate change was diagnosed in fens and bogs in the oceanic areas of the European northern fen region. In the case of all analyzed sites, there was a stepwise heterogeneity in the values of the analyzed indicators emerging around 1986–1996. The results highlight the importance of continued protection of natural and well-preserved peatlands to support their resilience under progressive, accelerating climate change. • Development of six meteorological indicators for peatland stability over 1946–2022. • Five mires analyzed in the gradient from subarctic Norway to Poland. • Meteorological indicators have predominantly negative trends and tendencies. • Highest risk of losing palsas, lowest risk of losing oceanic fens and bogs. • Protecting mires should assure their resilience to climatic change.