Comments: 

Data was collected at mesic meadow site in Adventdalen valley (78.19ºN, 15.93ºE) of Svalbard in July 2014. A warming treatment by Open Top Chambers (OTCs) was initiated on the site in 2003. Every year between 2003 and 2014, OTCs were placed at the site in late spring and removed each autumn. Within each block, plots were also randomly distributed between three levels of a grazing treatment by captive Barnacle Geese in 2003-2005: no grazing (UG), intermediate (low) grazing (LG), and high grazing, (HG). Grazing treatments were discontinued after 2005. Site setup and treatments are further described in Cooper et al 2004, 2006.

In summer 2014, plots were point-framed using a 0.75m x 0.75m point-frame with 100 evenly-spaced grid points to assess community composition. Each piece of living and dead material at a gridpoint was tallied to the species level where possible; in some cases, lichens could only be identified to the genus level. Dead material, biological crust, or bare substrate (i.e. rock) were also possible “hits”. The total number of “hits” per plot was then greater than 100 because many points had more than one type of cover present. 

At each gridpoint, the height of the vascular plant canopy layer was measured. The measurements from all points where vascular plants were present were averaged to produce a per-plot vascular plant canopy height. We also counted the total number of flowers on all vascular plant species in the plot. 

Additional measurements were taken on five individuals of dominant species (grass Alopecurus magellanicus, forb Bistorta vivipara, and shrub Salix polaris) in each plot. For A. magellanicus we measured the length of the longest leaf and the height of the flowering stalk. For S. polaris and B. vivipara we measured leaf size (length and width, and their product = area) for five leaves per plot.

References:

Cooper E J, Jonsdottir I S and Pahud A 2006 Grazing by captive Barnacle geese affects graminoid growth and productivity on Svalbard Mem. Natl Inst. Polar Res 59 1–16

Cooper E, Jónsdóttir I S, Chaput D, Kuijper D, Loonen M, Pahud A, Sjögersten S, Ubels R, Wal R Van Der, Woodin S and Huiskes A 2004 Climate change and goose grazing on Svalbard’s tundra ACIA International Symposium on Climate Change in the Arctic vol 2pp 1–3

variables in the file Adventdalen_mesic_2014_community.csv:

plot: first letter (D) = mesic site; second letter (C,D,E,F,G) = block; third letter = grazing treatment (U=ungrazed, L=low grazing, H=high grazing); fourth letter = warming treatment (T=warmed, A=ambient)
block: block, extracted from plot
warming: OTC (warmed) vs ambient, extracted from plot
grazing: grazing treatment, extracted from plot
combined_trt: concatenated factor of warming and grazing treatments
date_sampled: sampling date (day of year)
Dead_D_Salix_polaris: dead Salix polaris hits (deciduous shrub)
Dead_E_Dryas_octopetala: dead Dryas octopetala hits (evergreen shrub)
Dead_F_Bistorta_vivipara: dead Bistorta vivipara hits (forb)
Dead_F_Stellaria_crassipes: dead Stellaria crassipes hits (forb)
Dead_G_Alopecurus_borealis: dead Alopecurus borealis hits (grass)
Dead_G_Dupontia: dead Dupontia spp hits (grass)
Dead_G_Poa_alpina: dead Poa alpina hits (grass)
Dead_G_Poa_arctica: dead Poa arctica hits (grass)
Dead_G_unknown_graminoid: dead hits of unknown/unidentifiable graminoids
Dead_R_Luzula_confusa: dead Luzula confusa hits (rush)
Dead_R_Luzula_nivalis: dead Luzula nivalis hits (rush)
Dead_VP_litter: dead hits of unidentifiable vascular plant litter
lichen_Lecanora: number of times (out of 100 points) a Lecanora spp. lichen was the topmost hit of the bottom moss/lichen/substrate level
lichen_Nephroma: number of times (out of 100 points) a Nephroma bellum lichen was the topmost hit of the bottom moss/lichen/substrate level
lichen_Ochrelechia: number of times (out of 100 points) an Ochrelechia andogyna lichen was the topmost hit of the bottom moss/lichen/substrate level
lichen_Peltigera: number of times (out of 100 points) a Peltigera spp. lichen was the topmost hit of the bottom moss/lichen/substrate level
lichen_Stereocaulon: number of times (out of 100 points) a Stereocaulon alpinum lichen was the topmost hit of the bottom moss/lichen/substrate level
lichen_Thamnolia: number of times (out of 100 points) a Thamnolia vermicularis subsp. subuliformis lichen was the topmost hit of the bottom moss/lichen/substrate level
Live_D_Salix_polaris: live Salix polaris leaf/stem hits (deciduous shrub)
Live_D_Salix_woody: Salix polaris thick woody central stem hits (deciduous shrub)
Live_E_Dryas_octopetala: live Dryas octopetala leaf/stem hits (evergreen shrub)
Live_E_Dryas_woody: Dryas octopetala thick woody central stem hits (evergreen shrub)
Live_F_Bistorta_vivipara: live Bistorta vivipara hits (forb)
Live_F_Cerastium_arcticum: live Cerastium arcticum hits (forb)
Live_F_Pedicularis_dasyantha: live Pedicularis dasyantha hits (forb)
Live_F_Saxifraga_hirculus: live Saxifraga hirculus hits (forb)
Live_F_Saxifraga_oppositifolia: live Saxifrage oppositifolia hits (for)
Live_F_Stellaria_crassipes: live Stellaria crassipes hits (forb)
Live_G_Alopecurus_borealis: live Alopecurus borealis hits (grass)
Live_G_Dupontia: live Dupontia spp hits (grass)
Live_G_Poa_alpina: live Poa alpina hits (grass)
Live_G_Poa_arctica: live Poa arctica hits (grass)
Live_G_unknown_graminoid: live hits of unkown/unidentifiable graminoids
Live_R_Luzula_confusa: live Luzula confusa hits (rush)
Live_R_Luzula_nivalis: live Luzula nivalis hits (rush)
moss_Anthelia_juratzkana: number of times (out of 100 points) an Anthelia juratzkana moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Aulacomium_green: number of times (out of 100 points) an Aulacomnium palustre moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Aulacomium_yellow: number of times (out of 100 points) an Aulacomnium turgidum moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Ditrichum: number of times (out of 100 points) a Ditrichum flexicaule lichen was the topmost hit of the bottom moss/lichen/substrate level
moss_Hylocomium: number of times (out of 100 points) a Hylocomium splendens moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Polytrichum: number of times (out of 100 points) a Polytrichum commune moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Ptilidium: number of times (out of 100 points) a Ptilidium ciliare moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Racomitrium: number of times (out of 100 points) a Racomitrium lanuginosum moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Sanionia: number of times (out of 100 points) a Sanionia uncinata moss was the topmost hit of the bottom moss/lichen/substrate level
moss_Tomentypnum: number of times (out of 100 points) a Tomentypnum nitens moss was the topmost hit of the bottom moss/lichen/substrate level
mushroom: number of times (out of 100 points) a mushroom was the topmost hit of the bottom moss/lichen/substrate level
Black_crust: number of times (out of 100 points) biological crust was the topmost hit of the bottom moss/lichen/substrate level
chasm_bare_ground: number of times (out of 100 points) bare ground was the topmost hit of the bottom moss/lichen/substrate level, or a rupture in the surface prevented anything from growing
goose_droppings: number of grid squares with goose droppings present
grub_holes: number of goose grub holes in the plot
reindeer_droppings_summer: number of groups of summer droppings of reindeer in the plot
reindeer_droppings_winter: number of groups of winter droppings of reindeer in the plot
Stone: number of times (out of 100 points) a stone was the topmost hit of the bottom moss/lichen/substrate level
Total_cover: Total of all hits in plot (>100 grid points because usually more than one “hit” per point)
Total_live_VP: total of all live hits of deciduous and evergreen shrubs, forbs, grasses, and rushes
Total_dead_VP: total of all dead hits of deciduous and evergreen shrubs, forbs, grasses, and rushes
Total_Salix_live: total hits of live Salix polaris and its woody parts
Total_Dryas_live: total hits of live Dryas octopetala and its woody parts
Total_F_live: total of all live forb hits
Total_F_dead: total of all dead forb hits
Total_G_live: total of all live grass hits
Total_G_dead: total of all dead grass hits
Total_R_live: total of all live rush hits
Total_R_dead: total of all dead rush hits
Total_moss: number of times (out of 100 points) any moss was the topmost hit of the bottom moss/lichen/substrate level
Total_lichen: total of all lichen hits: number of times (out of 100 points) any lichen was the topmost hit of the bottom moss/lichen/substrate level
Total_live_cover: sum of Total_live_VP, Total_moss, and Total_lichen
Height_average: average height (in mm) of canopy at all grid points, including points where height=0
Hits_straight_to_base: number of points where no vascular plants present and there is only a moss/lichen/substrate level
Height_average_notzeroes: average height (in mm) of canopy at all grid points where vascular plants are present
Species_richness: number of species in plot (can include species which are not “hits” - extra species in the matrix were also counted)
flr_Alopecurus: number of Alopecurus stalks flowering in plot on sample day
flr_Poa_alpina: number of Poa alpina stalks flowering in plot on sample day
flr_Poa_arctica: number of Poa arctica stalks flowering in plot on sample day
flr_Luzula_confusa: number of Luzula confusa stalks flowering in plot on sample day
flr_Luzula_nivalis: number of Luzula nivalis stalks flowering in plot on sample day
flr_Dryas_octopetala: number of Dryas octopetala flowers in plot on sample day
flr_Bistorta_vivipara: number of Bistorta vivipara flowers in plot on sample day
flr_Cerastium_arcticum: number of Cerastium arcticum flowers in plot on sample day
flr_Pedicularis_dasyantha: number of Pedicularis dasyantha flowers in plot on sample day
flr_Saxifraga_hirculus: number of Saxifraga hirculus flowers in plot on sample day
flr_Stellaria_crassipes: number of Stellaria crassipes flowers in plot on sample day
flr_Cardamine: number of Cardamine bellidifolida flowers in plot on sample day
flr_Dupontia: number of Dupontia stalks flowering in plot on sample day
Salix_male_flr: number of Salix polaris male flowers in plot on sample day
Salix_female_flr: number of Salix polaris female flowers in plot on sample day
Salix_all_flr: number of total Salix polaris flowers in plot on sample day
Salix_avg_lf_length: average length (mm) of five Salix polaris leaves measured in plot
Salix_avg_lf_width: average width (mm) of five Salix polaris leaves measured in plot
Salix_avg_lf_area: average area (l*w) (mm) of five Salix polaris leaves measured in plot
Alopecurus_avg_lf_length: average length (mm) of longest leaves of five Alopecurus measured in plot
Alopecurus_avg_stalk_length: average length (mm) of flowering stalks of five Alopecurus measured in plot (NA indicates plot had no flowering stalks)
Bistorta_avg_lf_length: average length (mm) of five Bistorta vivipara leaves measured in plot
Bistorta_avg_lf_width: average width (mm) of five Bistorta vivipara leaves measured in plot
Bistorta_avg_lf_area: average length (mm) of five Bistorta vivipara leaves measured in plot