Point frame vegetation data collected 1989-2023 at the International Tundra Experiment (ITEX) experimental warming plots and the Toolik-Imnavait 1 km ambient grids in the North Slope of Alaska

The Arctic is warming at more than twice the rate of the global average. The International Tundra Experiment (ITEX) was established in the early 1990s to understand the effects of environmental variability as a result of climate change on tundra vegetation. This data publication includes tabular plant community composition and structure data for four sites in the North Slope of Alaska, USA that are part of the ITEX: 1) 1-square kilometer (km²) ambient grid near Toolik Lake (85 plots), 2) 1 km² ambient grid near Imnavait Creek (71 plots), 3) one experimentally warmed manipulated site near Toolik Lake (21 control plots and 21 treated plots), and 4) a snow depth manipulated site near Toolik Lake (25 control plots and 23 treated plots). Treated plots were warmed with open-top chambers which raised the ambient air temperature 2-3 degrees Celsius. Data at the two ambient sites were collected approximately every four to six years from 1989 to 2023. The experimentally warmed/snow manipulated plots were sampled approximately every two to five years from 1994-2023. Measurements at points on each plot include: the height of the top (canopy) and bottom (understory) vegetation structures relative to the ground; whether the vegetation was live or standing dead; and whether the vegetation was a woody or non-woody structure. Species, or the large taxa, was also recorded.These data were collected as part of an ongoing monitoring study that is part of the International Tundra Experiment (ITEX). The purpose of the study is to understand the long-term effects of environmental variablility as a result of climate change on tundra vegetation.For more information about this study and these data, see Wahren et al. (2005).