The role of cold stratification duration in the germination of carnivorous plants under changing environmental conditions

Climate change, distinct from short-term temperature fluctuations, encompasses long-term shifts in environmental conditions and poses a major threat to biodiversity—particularly for habitat-specialist species such as Drosera intermedia and Drosera rotundifolia . These carnivorous plants rely on the unique conditions of peat bogs, including high and stable soil moisture, low pH, and nutrient-poor substrates. This ex situ study investigated the effect of cold stratification duration and temperature interruption (simulating winter heat waves) on seed germination. Seeds were exposed to −10°C for 5 to 25 days, with or without a 5-day warming period at 1°C. Control seeds (no stratification) exhibited low germination rates (10–26%), while interrupted stratification increased germination to as much as 60%, suggesting a potential adaptive response to increasingly variable winter temperatures. Significant differences were also found between populations, possibly reflecting local environmental factors such as soil moisture. These results indicate that winter warming events may alter both the timing and success of seed germination, with implications for population persistence. Understanding such mechanisms is essential for the effective conservation and restoration of peatland ecosystems under climate change.