Arctic Vegetation Archive-Alaska: ATLAS-1.
Vegetation from 15 releves within 8 different grids at Barrow, Atqasuk, Ivotuk and Oumalik were described as part of the NSF-funded Arctic Transition in Land-Atmosphere System (ATLAS) project. The full ATLAS Transect also includes locations at Council and Quartz Creek, which are in the ATLAS-2 dataset (Raynolds et al. 2002). The focus of the ATLAS project was to improve understanding of controls over spatial and temporal variability of terrestrial processes in the Arctic that have potential consequences for the climate system, i.e., processes that affect the exchange of water and energy with atmosphere, the exchange of radiatively active gases with the atmosphere, and delivery of freshwater to the Arctic Ocean. The purpose of the ATLAS-1 studies was: 1) to characterize the major zonal vegetation types found along the North Slope climate gradient, 2) to quantify differences between acidic and non-acidic tundra along the same gradient, and 3) to investigate relationships between plant biomass, Leaf Area Index (LAI), and Normalized Difference Vegetation Index (NDVI). The data reported here are from an ATLAS study by D. A. Walker and colleagues titled Arctic Climate Change, Substrate and Vegetation (OPP-9732706). The data from fieldwork conducted in 1998 and 1999 are in a data report by Edwards et al. (2000).
Grids were delineated as follows: 100 m x 100 m grids were established at Atqasuk (A-1 (1 grid)), Barrow (B-1 (1 grid)), and Ivotuk (I-1, I-2, I-3, I-4 (4 grids)), while at Oumalik 50 m x 50 m grids (O-1 and O-2 (2 grids)) were established. Subjectively located within the grids were one or more circular (10 meter in diameter, except for Oumalik, where they were 5 meter in diameter) releves. Where present, location information for the releves within the grid is given in the remarks field. The 15 releves represent microsites within the grids related to, for example patterned ground features. These microsites were labeled with the letters A, B, C as needed. Plots occur in 14 plant communities within 5 broad habitat types including: a) willow shrub vegetation of riparian areas and warm habitats (south-facing slopes) (1 plot), b) sedge grass and dwarf shrub mire and fen vegetation (2 plots), c) bog vegetation, acidic mires, including tussock tundra (6 plots), d) frost boil vegetation in nonacidic tundra (1 plot), and e) dry and mesic dwarf-shrub and graminoid vegetation on non-acidic substrate (5 plots).
GPS coordinates were obtained for most grid corners. Species and environmental data (including subjective site assessments, soil physical variables, spectral data) were collected in the field and plant samples (biomass) and soil samples (pH) were brought back to the lab for analysis.
These data were subsequently used in several reports and publications listed below.
Edwards, E. J., A. Moody, and D. A. Walker. 2000. A western Alaskan transect to examine interactions of climate, substrate, vegetation, and spectral reflectance: ATLAS grids and transects, 1998-1999. ARCSS-ATLAS-Northern Ecosystem Analysis and Mapping Laboratory data report. Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA.
Jia, G. J., H. E. Epstein, and D. A. Walker. 2002. Spatial characteristics of AVHRR-NDVI along latitudinal transects in northern Alaska. Journal of Vegetation Science 13:315-326.
Riedel, S. M., H. E. Epstein, D. A. Walker, D. L. Richardson, M. P. Calef, E. Edwards, and A. Moody. 2005a. Spatial and temporal heterogeneity of vegetation properties among four tundra plant communities at Ivotuk, Alaska, U.S.A. Arctic, and Alpine Research 37:25-33.
Riedel, S. M., H. E. Epstein, and D. A. Walker. 2005b. Biotic controls over spectral reflectance of arctic tundra vegetation. International Journal of Remote Sensing 26:2391-2405.
Walker, D. A., G. J. Jia, H. E. Epstein, M. K. Raynolds, F. S. Chapin III, C. Copass, L. D. Hinzman, J. A. Knudson, H. A. Maier, G. J. Michaelson, F. Nelson, C. L. Ping, V. E. Romanovsky and N. Shiklomanov. 2003. Vegetation-soil-thaw-depth relationships along a low-arctic bioclimate gradient, Alaska: synthesis of information from the ATLAS studies. Permafrost and Periglacial Processes. 14:103-123.
Walker, D. A., H. E. Epstein, J. G. Jia, A. Balser, C. Copass, E. J. Edwards, W. A. Gould, J. Hollingsworth, J. Knudson, H. A. Maier, A. Moody, and M. K. Raynolds. 2003. Phytomass, LAI, and NDVI in northern Alaska: Relationships to summer warmth, soil pH, plant functional types, and extrapolation the circumpolar Arctic. Journal of Geophysical Research 108, 8169, doi:10.1029/2001JD000986, D2.