Study Site
The study was conducted at Fortress Mountain (50.82°N, 115.21°W) - a non-active alpine ski resort, located 80 km West of Calgary, Alberta, in the Kananaskis Range of the Canadian Rocky Mountains (Figure 1A, B). The study site, called Bonsai, was a marsh meadow, about 1 ha in size with a topographic boundary outlined by: a headwall (~500 m high) to the south, an ephemeral tarn to the North, and ridges (~150 m high) to the East and West (Figure 1C). The site was mostly-flat with a moderate increasing slope of 6 degrees (2083 to 2086 m.a.s.l.) from the tarn to the base of the talus slopes (50 m distance). Because of the headwall to the South and ridge to the East, different portions of the wetland were shaded for long durations of time across the day and season, which promoted a deep snowpack, long snow-covered period, extended spring melt period, and a constrained growing season.
The soil at the site was comprised of a thin layer of pervious well-sorted sand above a semi-pervious layer of very fine silt across much of the wetland, with increased gravel near the headwall. Vegetation was comprised of shade tolerant wetland species, including:Equisetum , Salix , Castilleja raupii , andErigeron caespitosus . The hydrology of the site consisted of a deep water-table (>2 m) and two surface streams, one on the East and one on the West margin of the wetland. These streams met at a confluence in the North-Central section of the wetland, where they drained into the tarn, which then drained into Galatea Creek and downslope to the Kananaskis River (a tributary to the Bow River – a major river in the area and a tributary of the South Saskatchewan River). For more information about the site characteristics please refer to Hrach et al. (2021).