Documentation Revision Date: 2017-01-24
Data Set Version: V1
The study plots were subjectively located in plant communities that occurred in six broad habitat types. A modified Hult-Sernander scale was used to determine the vegetation percent cover classes. The data are provided according to the original source (Churchill, 1955) and also according to the listings provided in TURBOVEG, a database for managing vegetation-plot data (see http://www.synbiosys.alterra.nl/turboveg/).
There are two data files in comma-separated format (.csv) with this data set.
Churchill, E.D., D.A. Walker, A.L. Breen, and L.A. Druckenmiller. 2017. Pre-ABoVE: Arctic Vegetation Plots, Umiat, North Slope, Alaska, 1951. ORNL DAAC, Oak Ridge, Tennessee, USA. http://dx.doi.org/10.3334/ORNLDAAC/1370
Table of Contents
- Data Set Overview
- Data Characteristics
- Application and Derivation
- Quality Assessment
- Data Acquisition, Materials, and Methods
- Data Access
Data Set Overview
This data set provides vegetation cover and plot data collected in 1955 from the Umiat region of Alaska. Early vegetation sampling on Alaska's North Slope was undertaken by Ethan D. Churchill while stationed at Umiat on the Colville River. Field work was conducted in July and August of 1951 to identify plant communities and to determine their relationship to environmental conditions.
Vegetation species are listed and percent cover classes are provided according to a modified Hult-Sernander scale. Plot data includes moisture, topographic position, slope, aspect, shape, and size.
The data are provided according to the original source (Churchill, 1955) and also according to the listings provided in TURBOVEG, a database for managing vegetation-plot data (see http://www.synbiosys.alterra.nl/turboveg/).
Project: Arctic-Boreal Vulnerability Experiment (ABoVE)
The Arctic-Boreal Vulnerability Experiment (ABoVE) is a NASA Terrestrial Ecology Program field campaign based in Alaska and western Canada between 2016 and 2021. Climate change in the Arctic and Boreal region is unfolding faster than anywhere else on Earth. ABoVE seeks a better understanding of the vulnerability and resilience of ecosystems and society to this changing environment.
These data were obtained from the Alaska Arctic Geoecological Atlas (http://agc.portal.gina.alaska.edu), which provides access to existing Arctic vegetation plot and map data in support of the ABoVE campaign.
Spatial Coverage: Umiat, Alaska
ABoVE Grid Location: Ahh1Avv0
Spatial Resolution: Point resolution
Temporal Coverage: 1951-07-01 to 1951-08-31
Temporal Resolution: Each plot was sampled once
Study Area (All latitude and longitude given in decimal degrees)
|Site||Westernmost Longitude||Easternmost Longitude||Northernmost Latitude||Southernmost Latitude|
Data File Information
There are two data files with this data set in comma-separated (.csv) format. The files provide the vegetation species found at 51 plots as well as the percent ground cover occupied by the species and plot data. These data may also be found in the TURBOVEG database. The files include the TURBOVEG accession numbers as well as the original plot nomenclature and numbering. There are also three companion files which provide plot photos and research information.
Table 1. Data files
|Data File Name||Description|
|Umiat_Environmental_Data.csv||Plot data including soil code, moisture, slope, aspect, and topography data. Also includes percent groundcover from Mosses and Lichens|
|Umiat_Species_Data.csv||The estimated percent land cover by species per plot according to a modified Hult-Sernander scale. The plots are named according to the original stand numbers and the TURBOVEG accession numbers.|
|Umiat_Plot_Photos.pdf||Photos of the plots at Umiat in .pdf format|
|Umiat_Veg_Plots.pdf||A pdf of this guide document|
Table 2. Variables in the file Umiat_Environmental_Data.csv
|10||PLOT_SHAPE||All plots are reported as “square”|
|17||STAND_LOCATION_DESCRIPTION||General description of the plot|
Table 3. Variables in the file Umiat_Species_Data.csv
|Column number||Column header||Description|
|1||PASL_TAXON_SCIENTIFIC_ NAME||Current nomenclature according to the Panarctic Species List (PASL)|
|2||PASL_TAXON_SCIENTIFIC_ NAME_AU||Current nomenclature according to the Panarctic Species List (PASL) with the data authors (AU) name|
|3||DATASET_TAXON||Data set taxonomy|
|4-55||TURBOVEG_NUM and DATASET_PLOT_ NUM||Two rows of 51 column headers. The first row is TURBOVEG accession numbers. Column headers= 12942-12992. The 2nd row is DATASET_PLOT_ NUM, the plot numbers as named in the original data set; column headers= STAND_#. For example, STAND_ 70. The data values are the estimated percent land cover by species per plot according to a modified Hult-Sernander scale where:
0= (none present)
+ (trace or 0.5 percent)
1 (covers less than 1/6)
2 (covers 1/6 to 1/8)
3 (covers 1/8 to 1/4)
4 (covers 1/4-1/2)
5 (covers 1/2 to 3/4)
6 (covers 3/4 to 4/4)
Example data are provided in Table 4 below.
Table 4. Example data from the file Umiat_Species_Data.csv
|DATASET_ PLOT_NUM||STAND_70||STAND _8||STAND_2||STAND_63|
|PASL_TAXON_SCIENTIFIC_ NAME||PASL_TAXON_SCIENTIFIC_ NAME_AU||DATASET_ TAXON|
|Alnus viridis s. crispa||Alnus viridis s. crispa (Dryl. ex Aiton) Turrill||Alnus crispa||1||1||0|
|Andromeda polifolia||Andromeda polifolia L.||Andromeda polifolia||0||1||0||0|
|Anemone richardsonii||Anemone richardsonii Hook.||Anemone richardsonii||0||0||0||0|
|Antennaria rosea s. pulvinata||Antennaria rosea s. pulvinata (Greene) R. J. Bayer||Antennaria isolepis||0||0||0||0|
|Arctagrostis latifolia||Arctagrostis latifolia (R. Br.) Griseb.||Arctagrostis latifolia||1||1||0||0|
Note: In five instances, taxa were lumped into a single taxon in the PASL: 1) Carex bigelowii s. ensifolia (Carex consimili and Carex lugens), 2) Equisetum arvense s. alpestre (Equisetum arvense var. boreale and Equisetum arvense var. boreale f. pseudo-varium), 3) Salix niphoclada (Salix brachycarpa var. mexiae and Salix niphoclada), 4) Salix glauca s. acutifolia (Salix desertorum, Salix glauca var. acutifolia, Salix glauca var alisceae), and 5) Salix pulchra (Salix pulchra and Salix pulchra var. palmeri).
Application and Derivation
These data represent a historical snapshot of conditions on the North Slope in the mid-20th century. They could be useful for studies of vegetation and land cover change and also for climate models.
Stands were not permanently marked and very little plot-specific environmental data were recorded.
Modifications to the source data:
1) A verbal description of aspect was converted to degrees and then crosswalk to TURBOVEG categorical data. Where slope was 0 and aspect was lacking, aspect values were converted to -1 “too flat to determine”.
2) Cover of mosses, lichens, and bare ground were converted from the modified Hult-Sernander scale codes (pluses and minuses were dropped due to lack of assigned value) to fractional ranges given in the text (Churchill, 1955). The midpoint in the fractional range was taken and converted to a cover percentage as indicated:
+ (trace or 0.5 percent),
1 (covers less than 1/6 of the area or 4 percent),
2 (covers 1/6 to 1/8 or 9 percent),
3 (covers 1/8 to 1/4 or 18 percent),
4 (covers 1/4 to 1/2 or 38 percent),
5 (covers 1/2 to 3/4 or 63 percent),
6 (covers 3/4 to 4/4 or 87 percent).
3) The pluses and minuses associated with cover values as presented in the publication were dropped (although not where plus alone indicates a trace) as these symbols were not assigned a value.
4) Habitat types and site moisture were assigned by D.A. ‘Skip’ Walker in January 2016.
5) Location data were not available for the plots so all were assigned the latitude and longitude for Umiat.
Data Acquisition, Materials, and Methods
The Umiat area is within the Northern Foothills section of the Arctic Foothills province on the slope north of the Brooks Range. The general topography of the upland is gently rolling hills and moderately flat valleys. The climate of the Umiat area is rigorous. The average annual temperature is 10.7 degrees F; the lowest recorded temperature was -63 degrees during February, the highest was 85 degrees during July, and the mean monthly temperature was below 0 degrees for the period December through April (Churchill, 1955).
The tundra vegetation of the Umiat area displays in many cases variation within a few feet or inches, probably as a result of the variation in environmental conditions accompanying a few inches difference in microrelief and resulting in a mosaic of microstands. Each stand has a homogeneity of micromosaics that is distinctive over a given area and is dissimilar to the distinctive homnogeneities of adjacent area. The elevation on the floodplain at Umiat is approximately 340 feet. Elevations of the ridges and tops of hills of the upland extend to 950 feet (Churchill, 1955).
Figure 2. Aerial view of the river and floodplain at Umiat, Alaska.
Early vegetation sampling on Alaska's North Slope was undertaken by Ethan D. Churchill while stationed at Umiat on the Colville River. Field work was conducted in July and August of 1951 to identify plant communities and to determine their relationship to environmental conditions.
In July and August of 1951, 51 stands (areas of unified vegetation) were subjectively located and sampled. Stands were determined by aerial photography and ground reconnaissance to ensure homogeneity. Ten, 1-square meter plots were systematically located as uniformly and widely as possible within homogeneous vegetation of the stand but restricted so that transitional areas into adjacent stands were avoided. Plant species cover was recorded using a modified Hult-Sernander scale where:
0 (none present),
+ (trace or 0.5 percent),
1 (covers less than 1/6),
2 (covers 1/6 to 1/8),
3 (covers 1/8 to 1/4),
4 (covers 1/4-1/2),
5 (covers 1/2 to 3/4), and
6 (covers 3/4 to 4/4).
Plant communities occurred in broad habitat types including:
1) Willow shrub vegetation of riparian areas and warm habitats (south-facing slopes) (2 plots),
2) Moist to wet acidic tussock and nontussock (Eriophorum vaginatum-Carex bigelowii-Sphagnum-Hylocomium) tundra (40 plots),
3) Dry acidic prostrate-shrub heaths (Arctous alpina, Salix phlebophylla, Empetrum heaths) (2 plots),
4) Frost boil vegetation in nonacidic tundra (Juncus biglumis, Saxifraga oppositifolia) (2 plots),
5) Alder communities (2 plots), and 6) Sedge grass and dwarf shrub mire and fen vegetation (3 plots) (Churchill, 1955).
Plot characterization data are also included with this data set. However, location data were not available for the plots so all were assigned the latitude and longitude for Umiat.
Churchill (1955), references Payne et al. (1951), Smith and Mertie (1930), Stenfansson and Whittington (1947), and Black and Barksdale (1948) regarding the geology and topography of the area.
Habitat types and site moisture were assigned by the primary contact D. A. ‘Skip’ Walker, in January 2016.
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).
Contact for Data Center Access Information:
- E-mail: firstname.lastname@example.org
- Telephone: +1 (865) 241-3952
Black, R. F., and W. L. Barksdale. 1948. Terrain and permafrost, Umiat Area, Alaska. Progress Report No. 5, Military Geology Section, U. S. Geol. Surv. Washington. 23 p.
Churchill, E. D. 1955. Phytosociological and environmental characteristics of some plant communities in the Umiat region of Alaska. Ecology. 36:606-627.
Payne, T. G., W.W. Dana, W. A. Fischer, George Gryc, E.H. Lathram, R.H. Morris, H.N. Tappan, and S.T. Yusler. 1951. Geology of the Arctic Slope of Alaska. Oil and Gas Investigations, Map 126 Sheet 1. U. S. Geol. Surv., Washington.
Smith, P. S., and J. B. Mertie, Jr. 1930. Geology and mineral resources of northwestern Alaska. U. S. Geol. Surv. Bull. 815. 351 p.
Stenfansson, K., and C. L. Whittington. 1947. Stratigraphy and structure of the Umiat anticline. Report No. 3, Geological Investigations Naval Pet. Res. No. 4, Alaska. U. S. Geol. Surv. Washington. 11 p.