The International Tundra Experiment (ITEX) is a long-term international collaboration of researchers examining the responses of arctic and alpine plants and ecosystems to climate change.Henry, GHR, and Molau, U. 1997. Tundra plants and climate change: the International Tundra Experiment. Global Change Biology, 3(S1): 1-9. Researchers measure plant responses to standardized, small-scale passive warming, snow manipulations, and nutrient additions. Researchers use small open-top chambers (OTCs) to passively increase mean air temperature by 1-2 °C.Marion, G. et al. 1997. Open-top designs for manipulating field temperature in high-latitude ecosystems. Global Change Biology, 3(S1): 20-32. The ITEX approach has been validated by tundra responses at the plot level.Hollister, RD and Webber, PJ. 2000. Biotic validation of small open-top chambers in a tundra ecosystem. Global Change Biology, 6: 835-842. The network has published meta-analyses on plant phenology, growth, and reproduction,Arft, AM, et al. 1999. Responses of tundra plants to experimental warming: Meta-analysis of the International Tundra Experiment. Ecological Monographs, 96(4): 491-511. composition and abundance,Walker, MD, et al. 2006. Plant community responses to experimental warming across the tundra biome. Proceedings of the National Academy of Sciences, 103(5): 1342-1346. and carbon flux.Oberbauer, SF, et al. Tundra CO2 fluxes in response to experimental warming across latitudinal and moisture gradients. Ecological Monographs, 77(2): 221-238. The ITEX network consists of more than 50 sites in polar and alpine locations around the world.ITEX Sites Spreadsheet
Canadian sites Alexandra Fiord, Ellesmere Island
Name of site leader(s): Greg Henry
University: University of British Columbia
Site elevation: 0-100m
Latitude (WGS84 decimal degrees): 78.8833° N
Longitude (WGS84 decimal degrees): 75.8000° W
Date site was established: 1987
Does your site have OTC's? Yes
Number of plots at your site (include OTCs control plots, etc.) 90 OTCs 99 controls
When were they established? 1993
Have they been closed? If so, when? No
Is there grazing at your site? No
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation, Cloud cover, Wind, global radiation etc.
Current or past data collection: Phenology, Point framing, Above ground plant traits, Flower counts, Fertilizer plots, Snowmelt dates, Snow addition and removal, GIS data, Drones (https://arcticdrones.org/), Phenocams (GoPros etc.), Transplant experiments, Plot photos, Soil moisture, Soil sampling, Succession studies
Main genera in OTC plots: Dryas, Salix, Cassiope, Vaccinium, Sedges, Grasses, Rushes, Saxifraga, Equisetum, Poppy, Oxyria, Draba, Mosses/Lichens, Fungi
Other nearby related study sites on Ellesmere: Sverdrup Pass, Princess Marie Bay, Hot Weather Creek,
Sverdrup Pass, Ellesmere Island, Nunavut
Name of site leader(s): Esther Lévesque, Josef Svoboda (1986-1994)
University: Université du Québec à Trois-Rivières (UQTR)
Site elevation: 180 m
Latitude (WGS84 decimal degrees): 79.14
Longitude (WGS84 decimal degrees): -79.7
Date site was established: 1990
Does your site have OTC's? No
Number of plots at your site (include OTCs control plots, etc.) 13 in total along altitudinal gradients (300m to ca. 700m) on two substrates (granite and dolomite) D1-D6 and G1-G7
When were they established? 1990
Have they been closed? If so, when? Yes, 1994
Is there grazing at your site? Insects, Ungulates, Hares (Lagomorphs)
Climate data: Air temperature >1m, Soil temperature, Precipitation, Soil temperature year-round (1986-1994)
Current or past data collection: Individual plant phenology, Above ground plant traits, Flower counts (total), Flower counts (per stage)
Main genera in plots: Papaver
Bylot Island, Nunavut
Name of site leader(s): Esther Lévesque
University: Université du Québec à Trois-Rivières
Latitude (WGS84 decimal degrees): 73.3652
Longitude (WGS84 decimal degrees): -79.0153
Nunatsiavut (Nain and Torr Bay)
Name of site leader(s): Laura Siegwart Collier, Luise Hermanutz
University: Memorial University
Latitude (WGS84 decimal degrees): 58.4774° N
Longitude (WGS84 decimal degrees): 62.8295° W
Date site was established: 2009
Nain Does your site have OTC's? Yes
Number of plots at your site (include OTCs control plots, etc.) 18
When were they established? 2009
Have they been closed? If so, when? Yes, the subsite is closed
Is there grazing at your site? No
Climate data: Air temperature >1m, Soil temperature, PAR, Soil moisture probe
Current or past data collection: Point framing, Flower counts (total), Plot photos, Fruit production
Main genera in OTC plots: Betula, Vaccinium, Empetrum, Rhododendron, Carex, Bryophytes, Lichen
Torr Bay Does your site have OTC's? Yes
Number of plots at your site (include OTCs control plots, etc.) 60
When were they established? 2009
Have they been closed? If so, when? No but visited infrequently (once 3–5 years)
Is there grazing at your site?
Climate data: Air temperature >1m Soil temperature, PAR, Soil moisture probe
Current or past data collection: Point framing, Flower counts (total), Fruit production
Main genera in OTC plots: Salix, Betula, Vaccinium, Empetrum, Rhododendron, Carex, Eriophorum, Poa, Juncus, Bryophytes, Lichen, Oxytropis
Tundra Ecosystem Research Station, Daring Lake Tundra Ecosystem Research Station, Daring Lake:https://www.enr.gov.nt.ca/en/services/research-and-data/tundra-ecosystem-research-station Name of site leader(s): Karin Clark
University: Government of the Northwest Territories
Latitude (WGS84 decimal degrees): 65 degrees 52 min N
Longitude (WGS84 decimal degrees): 111 degrees 32 min W
Date site was established: 1995
Does your site have OTC's? Currently have
Number of plots at your site (include OTCs control plots, etc.) 9
When were they established? Plots established 1995; OTCs in 2000
Have they been closed? If so, when? No
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation, radiation, wind speed and direction
Current or past data collection: Phenology, Point framing, Above ground plant traits, Flower counts, Snowmelt dates
Main genera in OTC plots: Salix, Betula, Vaccinium, Sedges, Saxifraga, Oxytropis
Qikiqtaruk (Herschel Island), Yukon
Name of site leader(s): Isla Myers-Smith
University: University of Edinburgh, Yukon Parks
Site elevation: 70m
Latitude (WGS84 decimal degrees): 69.6 N
Longitude (WGS84 decimal degrees): 138.9 W
Date site was established: 1999
Does your site have OTC's? Never had
Number of plots at your site (include OTCs control plots, etc.) 12
When were they established? 1999
Have they been closed? If so, when? No
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation
Current or past data collection: Phenology, Point framing, Above ground plant traits, Herbivory, Flower counts, Plot photos, Snowmelt dates, GIS data, Drones (https://arcticdrones.org/), Phenocams (GoPros etc.), Soil sampling, Shrub common garden
Main genera in OTC plots: Dryas, Salix, Betula, Sedges, Grasses, Mosses/Lichens
Garibaldi Park, BC, Canada
Garibaldi Park, BC, Canada:https://garibaldialpine.wixsite.com/garibaldialpine
Name of site leader(s): Cassandra Elphinstone, Courtney Collins, & Nathalie Chardon (2022-2024); Chelsea Little (2025–present)
University: University of British Columbia & Simon Fraser University
Site elevation: 1470m
Latitude (WGS84 decimal degrees): 49.927275
Longitude (WGS84 decimal degrees): -122.992919
Date site was established: 2022
Does your site have OTC's? Yes
Number of plots at your site (include OTCs control plots, etc.) 24
When were they established? 2022
Have they been closed? If so, when? No
Is there grazing at your site? Yes
Climate data: Plot level Air temperature, Soil temperature, radiation
Current or past data collection: Phenology, Point framing, Above ground plant traits, Flower counts, Phenocams (GoPros etc.), Plot photos, Soil moisture, Soil sampling
Main genera in OTC plots: Salix, Cassiope, Phyllodoce, Kalmia, Triantha, Pinguicula, Equisetum, Carex
Greenlandic sites Disko, Greenland
Name of site leader(s): Per Molgaard
University: University of Copenhagen
Site elevation: 10-100m
Latitude (WGS84 decimal degrees): 69.63N
Longitude (WGS84 decimal degrees): 42.17W
Date site was established: 1989 (last visit 2013)
Does your site have OTC's? No
Number of plots at your site (include OTCs control plots, etc.) 4
When were they established? 1992
Have they been closed? If so, when? Yes 1994
Is there grazing at your site? No
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation
Current or past data collection: Phenology, Point framing, Above ground plant traits, Herbivory, Flower counts
Main genera in OTC plots: Salix, Papaver, Caterpillars on willow
Arctic Station, Disko, Greenland Name of site leader(s): Anders Michelsen, Bo Elberling
University: University of Copenhagen
Mesic-dry heath tundra Site elevation: 95m
Latitude (WGS84 decimal degrees): 69 16 N
Longitude (WGS84 decimal degrees): 53 27 W
Date site was established: 20Does your site have OTC's? Only snow fences
Number of plots at your site (include OTCs control plots, etc.) 48
When were they established? 2012
Have they been closed? If so, when? still running
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation, Cloud cover
Current or past data collection: Point framing, Above ground plant traits, Below ground traits, Snow fences, Soil moisture, Drones, Soil sampling
Main genera in OTC plots: Dryas, Salix, Betula, Cassiope, Vaccinium, Sedges, Grasses, Mosses/Lichens
Wet sedge tundra Site elevation: 85m
Latitude (WGS84 decimal degrees): 69 26 N
Longitude (WGS84 decimal degrees): 53 47 W
Date site was established: 2013
Does your site have OTC's? Only snow fences
Number of plots at your site (include OTCs control plots, etc.) 48
When were they established? 2013
Have they been closed? If so, when? still running
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation, Cloud cover
Current or past data collection: Point framing, Above ground plant traits, Below ground traits, Snow fences, Snowmelt dates, Soil moisture, Drones, Soil sampling
Main genera in OTC plots: Salix, Sedges, Rushes, Equisetum, Mosses/Lichens
Zackenberg, Greenland
Name of site leader(s): Niels Martin Schmidt
University: Aarhus University
Site elevation: App. 55 m
Latitude (WGS84 decimal degrees): 74.47427
Longitude (WGS84 decimal degrees): -20.52895
Date site was established: 1996
Does your site have OTC's? Currently have
Number of plots at your site (include OTCs control plots, etc.) 20
When were they established? 2007
Have they been closed? If so, when? No
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation, Cloud cover
Current or past data collection: Phenology, Point framing, Flower counts, Plot photos, Snowmelt dates, Soil moisture, Soil sampling
Main genera in OTC plots: Salix, Cassiope, Vaccinium, Grasses, Mosses/Lichens
Zackenberg, Greenland
Name of site leader(s): Anders Michelsen
University: University of Copenhagen
Site elevation: 35m
Latitude (WGS84 decimal degrees): 74 30 N
Longitude (WGS84 decimal degrees): 21 00 W
Date site was established: 2004
Does your site have OTC's? Yes
Number of plots at your site (include OTCs control plots, etc.) 20
When were they established? 2004
Have they been closed? If so, when?
Is there grazing at your site? Yes
Climate data: Air temperature, Soil temperature, Snow depth, Precipitation