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International Tundra EXperiment (ITEX)
Primary Investigator: Robert D. Hollister

Brief Description:
This study seeks to quantify and improve the understanding of short-term and long-term responses of tundra vegetation to annual variation of and increase in temperature. This project provides data for improved prediction of the response of the tundra to climate change.  

To accomplish this the project will continue and expand a tundra warming experiment at Barrow and Atqasuk, Alaska.  This experiment, which has been in place in the Barrow since 1994 and at Atqasuk since 1996, has provided new insights on flower and growth responses to warming. This research is a contribution to the US NSF Arctic Observatory Network (AON) Program and the  International Tundra Experiment (ITEX). ITEX sites are located at 37 locations in 13 countries including all the Arctic Nations. ITEX uses small, passive, clear-plastic, open-top chambers to warm the tundra. The chambers raise the daily temperature of the tundra plant canopy by 1.5 to 2.0 ºC which is in the range predicted by global climate simulations.

Research Design:
There are 24 chambers and 24 control plots at each of the four sites studied.  This high amount of replication allows for detection of change in spite of the noise of the system.  The sites span gradients of  temperature, from cooler Barrow to warmer Atqasuk, and moisture, from wet meadow to dry heath tundra types.

Sites by treatment

Barrow
Atqasuk
Dry Heath
Wet Meadow
Dry Heath
Wet Meadow
Alopercurus alpinus Alopecurus alpinus Antennaria friesiana Betula nana
Arctagrostis latifolia Arctophila fulva Arctagrostis latifolia Calamagrostis spp.
Carex stans Calamagrostis holmii Armeria sibirica Carex aquatilis
Cassiope tetragona Cardamine pratensis Artemesia artica Carex rariflora
Draba lactea Carex stans Artemesia borealis Carex rotundata
Draba micropetala Carex subspathacea Carex bigelowii Dupontia psilosantha
Festuca brachyphylla Ceratium beeringianum Carex saxatilis Eriophorum angustifolium
Juncus biglumis Cochlearia officinalis Cassiope tertragona Eriophorum russeolum
Luzula arctica Draba lactea Diapensia lapponica Eriophorum scheuchzeri
Luzula confusa Draba micropetala Hierachloe alipina Luzula arctica
Oxyria digynia Dupontia fisheri Ledum palustre Luzula wahlenbergii
Papaver hultenii Eriophorum russeolum Luzula arctica Pedicularis sudetica
Papaver lapponicum Eriophorum scheuchzeri Luzula confusa Polygonum viviparum
Pedikalaris kanei Eriophorum triste Luzula wahlenbergii Salix polaris
Poa arctica Hierochloe pauciflora Minuartia obtusiloba Salix pulchra
Poa malacantha Juncus biglumis Polygonum bistorta  
Potentilla hyparctica Luzula arctica Salix phlebophylla  
Salix rotundifolia Luzula confusa Trisetum spicatum  
Saxifraga caespitosa Melandrum apetalum Vaccinium vitis-idaea  
Saxifraga cernua Petasites frigidus    
Saxifraga flagellate Poa arctica    
Saxifraga foliolosa Ranunculus nivalis    
Saxifraga nivalis Ranunculus pygmaeus    
Saxifraga punctata Salix pulchra    
Senecio atropurpureus Salix rotundifolia    
Stellaria laeta Saxifraga caespitosa    
Vaccinium vitis-idaea Saxifraga cernua    
  Saxifraga foliolosa    
  Saxifraga hieracifolia    
  Saxifraga hirculus    
  Stellaria humifusa    
  Stellaria laeta    

Measures Collected at all Sites:
Plant Phenology and Growth
Species Composition and Abundance
Screen Height Temperature
Canopy Temperature
Soil Temperature
Precipitation
Canopy Relative Humidity
Soil Moisture
Light Intensity
Wind Speed Near the Ground


Acknowledgements:
Funding for this research is provided by the Arctic Sciences Division of the Office of Polar Programs (OPP) of the National Science Foundation (NSF) (Award # OPP-) with logistics provided by the Barrow Arctic Research Consortium (BASC).