Study area
The field survey was conducted in an alpine meadow located in Shangri-La
County (27°37’40” N, 99°47’32” E; 3379 m), Northwest of Yunnan
Province, China. The study area was about 12 hectares, which was a small
valley basin surrounded by mountains. For the pollinators, the study
site could be regarded as an isolated area because the mountains were
mainly covered by coniferous forests and the nearest meadows were 2 km
away (straight-line distance) and separated by the forests. More than
120 flowering plant species grow in the meadow, including more than 55
plant species visited by bumble bees. The flowering season extends from
May to September. The most dominant plant is Polygonum
macrophyllum D. Don., which contributes to no less than 40% of the
coverage for this meadow. The next most dominant species areSanguisorba filiformis (Hook. f.) Hand. -Mazz., Anemone
obtusiloba D. Don., Pedicularis densispica Franch.,Phlomis atropurpurea Dunn. etc.