Arctic Vegetation Archive - Alaska: International Turdra Experiment Vegetation Plots.
The International Tundra Experiment (ITEX) is an international scientific collaboration to study the effects of climate change on tundra plant communities worldwide including multiple sites in northern Alaska (Arctic National Wildlife Refuge, Atqasuk, Barrow, Imnavait Creek, Toolik Lake) and across the circumpolar Arctic (Elmendorf 2014). ITEX long-term observations have resulted in numerous publications from individual sites, as well as several meta-analyses and syntheses (e.g. Walker et al. 2006, Elmendorf et al. 2012a, 2012b, Oberbauer et al. 2013).
The core experiment consists of a passive summer warming experiment using open-topped chambers, and use of common sampling protocols to document plant responses including measurements of growth, phenology, and community composition. ITEX sites are maintained by individual Principal Investigators who implement a subset of protocols specified in the ITEX manual (Molau and Molgaard 1996), as time and funding permit.
The ITEX data used in Elmendorf et al. (2012b) included a diversity of sampling methods: 1) point-frame data based on top only, top and bottom only, or all hits through the canopy, 2) ocular cover estimates, 3) stem counts, 4) biomass harvests, and 5) subplot frequency counts. Complete species lists are not reliably generated from this array of methods as they most likely miss rare species. In addition, species that are difficult to identify reliably (predominantly cryptogams) were lumped into easily recognized morpho-species for their analysis (Elmendorf 2014b). These data are therefore not archived in the Alaska Arctic Vegetation Archive’s Turboveg database because they do not satisfy the criterion of having complete species lists with associated cover abundance values.
The data from the 2012 published syntheses are archived in the Polar Data Catalogue (Elmendorf 2012c; see link below).
Select vegetation plot data are also archived in the TundraPlot database (GIVD ID 00-00-005). The description that accompanies their GIVD entry is as follows:
"All plots were set up as part of long-term monitoring studies, but data included here are only the most recent survey year per site. Plants were identified to species whenever possible, otherwise to genus. Cover was estimated slightly differently for each site in the database (e.g. some using the point-intercept method, some by visual cover estimation, etc. - see metadata) but all values provided have been converted to cover. The total cover of bryophytes and lichens also is provided for most sites."
References
Elmendorf, S. C. 2014. Overview of the International Tundra Experiment (ITEX) data sets and discussion of point data. In Walker, D.A. (Ed). Alaska Arctic Vegetation Archive Workshop, Boulder, Colorado, October 14-16, 2013. CAFF Proceedings Report #11. Akureyri, Iceland. ISBN: 978-9935-431-29-5.
Elmendorf, S. C., G. H. R. Henry, R. D. Hollister, R. G. Björk, A. D. Bjorkman, T. V. Callaghan, L. S. Collier, E. J. Cooper, J. H. C. Cornelissen, T. A. Day, A. M. Fosaa, W. A. Gould, J. Grétarsdóttir, J. Harte, L. Hermanutz, D. S. Hik, A. Hofgaard, F. Jarrad, I. S. Jónsdóttir, F. Keuper, K. Klanderud, J. A. Klein, S. Koh, G. Kudo, S. I. Lang, V. Loewen, J. L. May, J. Mercado, A. Michelsen, U. Molau, I. H. Myers-Smith, S. F. Oberbauer, S. Pieper, E. Post, C. Rixen, C. H. Robinson, N. M. Schmidt, G. R. Shaver, A. Stenström, A. Tolvanen, Ø. Totland, T. Troxler, C.-H. Wahren, P. J. Webber, J. M. Welker, and P. A. Wookey. 2012a. Global assessment of experimental climate warming on tundra vegetation: heterogeneity over space and time. Ecology Letters 15:164-175.
Elmendorf, S. C., G. H. R. Henry, R. D. Hollister, R. G. Björk, N. Boulanger-Lapointe, E. J. Cooper, J. H. C. Cornelissen, T. A. Day, E. Dorrepaal, T. G. Elumeeva, M. Gill, W. A. Gould, J. Harte, D. S. Hik, A. Hofgaard, D. R. Johnson, J. F. Johnstone, I. S. Jónsdóttir, J. C. Jorgenson, K. Klanderud, J. A. Klein, S. Koh, G. Kudo, M. Lara, E. Lévesque, B. Magnússon, J. L. May, J. A. Mercado-Dıaz, A. Michelsen, U. Molau, I. H. Myers-Smith, S. F. Oberbauer, V. G. Onipchenko, C. Rixen, N. Martin Schmidt, G. R. Shaver, M. J. Spasojevic, Þ. E. Þórhallsdóttir, A. Tolvanen, T. Troxler, C. E. Tweedie, S. Villareal, C.-H. Wahren, X. Walker, P. J. Webber, J. M. Welker, and S. Wipf. 2012b. Plot-scale evidence of tundra vegetation change and links to recent summer warming. Nature Climate Change 2:453-457.
Elmendorf, S. et al., 2012c. Global Tundra Vegetation Change - 30 years of plant abundance data from unmanipulated and experimentally-warmed plots. www.polardata.ca, CCIN reference number 10786.
Molau, U., and P. Molgaard. 1996. ITEX manual. Dansk Polar Center, Copenhagen.
Oberbauer, S. F., S. C. Elmendorf, T. G. Troxler, R. D. Hollister, A. V. Rocha, M. S. Bret-Harte, M. A. Dawes, A. M. Fosaa, G. H. R. Henry, T. T. Høye, F. C. Jarrad, I. S. Jónsdóttir, K. Klanderud, J. A. Klein, U. Molau, C. Rixen, N. M. Schmidt, G. R. Shaver, R. T. Slider, Ø. Totland, C.-H. Wahren, and J. M. Welker. 2013. Phenological response of tundra plants to background climate variation tested using the International Tundra Experiment. Philosophical Transactions of the Royal Society B: Biological Sciences 368:20120481.
Walker, M. D., C. H. Wahren, R. D. Hollister, G. H. R. Henry, L. E. Ahlquist, J. M. Alatalo, M. S. Bret-Harte, M. P. Calef, T. V. Callaghan, A. B. Carroll, H. E. Epstein, I. S. Jónsdóttir, J. A. Klein, B. Magnússon, U. Molau, S. F. Oberbauer, S. P. Rewa, C. H. Robinson, G. R. Shaver, K. N. Suding, C. C. Thompson, A. Tolvanen, Ø. Totland, P. L. Turner, C. E. Tweedie, P. J. Webber, and P. A. Wookey. 2006. Plant community responses to experimental warming across the tundra biome. Proceedings of the National Academy of Sciences of the United States of America 103:1342-1346.
