Study site
The study was performed in a longitudinal fen, the Rastmyran wetland (60°07’35”N 17°53’56”E), which is situated two hours north of Stockholm. The wetland (about 2.5 km long and 0.3 km wide) is situated in a headwater area near a local water divide (Åhlén, et al. 2022) and transected by a stream running south to north (Fig. 2). The wetland is seasonally flooded (wetter in winter-spring and drier in summer-autumn, Åhlén, Jarsjö and Hambäck 2023) and undisturbed from current human activities with no grazing, forestry, water regulation or other activities. The wetland is relatively isolated from adjacent wet habitats and surrounded by a coniferous forest. Within the wetland, there are patches of willow thickets and single bushes, but the vegetation consists mainly of typical wetland plants such as grasses, sedges, horsetails and forbs (e.g., Lysimachia and Lythrum) .