Background and aims: Nitrogen (N) fixation in feather moss-cyanobacteria associations is a major source of N for boreal ecosystems. However, mosses experience significant shifts in their moisture status due to daily and yearly fluctuations in sunlight, temperature and precipitation. While the effects of drying and rewetting on nutrient leaching and photosynthesis in mosses have been studied, no attempt has been made to assess the consequences for N fixation in feather mosses. Methods: We conducted an experiment in which we dried (3 day at 28 °C;