Events hidden in winter warming: Effects of recurrent soil freeze-thaw cycles on ecosystem functions in the temperate zone

点击翻译按钮获取中文摘要

Ongoing global warming is expected to increase the recurrence of soil freeze-thaw cycles (FTC) in cool-temperate regions due to decreases in snow cover and increased variability of air temperature in winter. FTC currently occur in more than half of the northern hemisphere, therefore it is important to explore the ecological implications of their altered regimes due to climate change. Knowledge of FTC effects on plant communities is scarce, although plants may be the decisive factor in controlling ecosystem functions such as nutrient retention. Evidence suggests that FTC alter plant productivity, carbon allocation and competition between. Shifts in frequency and timing of FTC are capable of altering ecosystem stability and ecosystem services, vegetation composition and species distributions. Nutrient cycling is altered via physical disruption and changes in microbial activity, leading to nutrient leaching and trace gas loss. These processes indirectly affect human interests (e.g. productivity, water quality, greenhouse gas emissions). We want to analyze effects of intensified FTC in winter for the biomass production of grassland and heath in a field experiment, thereby also exploring processes behind effects of FTC on plants addressing N-nutrition, photosynthetic activity, root injury, and biotic interactions such as plant competition and root mycorrhization.