Supplement to: Walker, Donald A; Kuss, Patrick; Epstein, Howard E; Kade, Anja N; Vonlanthen, Corinne M; Raynolds, Martha K; Daniëls, Frederikus J A (2011): Vegetation of zonal patterned-ground ecosystems along the North America Arctic bioclimate gradient. Applied Vegetation Science, 14(4), 440-463, https://doi.org/10.1111/j.1654-109X.2011.01149.x