Plant community shift across sharp soil moisture transition at the Kungsängen meadow
The plant community was assessed in plots along two permanent transects stretching from the wetter part close to the Fyris river to a mesic-dry part of the meadow (Fig. 1). A total of 85 plant species were recorded along transects 1 and 4 (73 and 61 species, respectively; Supplementary datafile 3), with the highest numbers, 24–29 plant species, recorded in plots 13–16 in transect 1 (Fig. S2), just on the mesic-dry side of the moisture transition. In accordance with earlier inventories (Sernander, 1948; Zhang, 1983), the number of recorded plant species dropped rapidly in the wet part of the meadow with on average only six species per plot across plots 17–25. There is a slight levee along the river where the number of recorded species increases again (Fig. S2). nMDS ordination of the plant community along transects 1 and 4 demonstrates the distinct separation between plots in the mesic-dry part east of the soil sampling compared to the wet part west of the soil sampling (Fig. 2), and with a transition from Carex disticha to Carex acuta dominance at the border (Zhang, 1983). Alopecurus pratensis andStellaria graminea were detected in all plots in the mesic-dry area and Poa trivialis , Phleum pratense andTrifolium repens were other highly abundant species in the mesic-dry area (Supplementary datafile 3). Fritillaria meleagriswas frequent in plots in the mesic-dry part to the east of the soil sampling (and also in elevated plots closest to the river) but did not occur in the wetter parts of the transects (Fig. S2). The distinctC. acuta dominated community in the wet side of the meadow has been previously reported (Zhang, 1983). Other frequently observed species in the wet area include Equisetum fluviatile , Carex disticha and Galium palustre . Soil sampling in early June confirmed that mean gravimetric soil moisture was significantly different (p<0.001; t = -5.1812, nwet = 10; ndry = 10) on either side of the plant community transition border, with 76% and 34% soil moisture in the wet compared to the mesic-dry side of the meadow (Fig. S3).
Characterizing the belowground microeukaryotic community composition