This species data is extracted from a report on a summary of environmental,
soil, and vegetation information collected from 81 study plots at the Toolik
Lake research site, located in the northern Arctic Foothills of the Brooks
Range, Alaska (68 deg. 37' N, 149 deg. 32' W). It brings together for easy
reference all the available information collected from the plots. This
information is being used for the classification, mapping and analysis of the
geobotanical factors in the Toolik Lake and Imnavait Creek region. A separate
equivalent data report is available for 71 permanent plots at Imnavait Creek
(Walker et al., 1987).
Methods and data summaries
Reconnaissance survey, sampling dates, and plot locations
A reconnaissance survey was conducted in August 1988 to define the primary
vegetation types in the Toolik Lake area. Unknown plants were collected and many
informal partial releve were sampled with reference to spectral signatures on a
1:50,000-scale color-infrared photograph. A total of 22 preliminary vegetation
types were defined based on habitat and dominant species (Table 1).
Formal releve sampling for the plots in this data report was done during
the period 1-26 August 1989. An attempt was made to sample at least three
releve for each of the types defined in 1988, but this was not possible in all
cases (Tables 1 and 2).
The plots were located in homogeneous areas of vegetation using the
centralized replicate method of the Braun-Blanquet approach to vegetation
classification (Mueller-Dombois and Ellenberg, 1974; Westhoff and van der
Maarel, 1978).
Nearly all of the plots are permanently marked. The exception is plot
SWT-55. The plots are marked with 48-inch (122-cm) wooden stakes, and aluminum
tags at the base of the stakes with the plot numbers. Some of the stakes have
broken off since sampling. We intend to replace all of
the wooden stakes with tall plastic stakes.
Forty of the plots are located along transects as follows:
1. West-facing toposequence of Itkillik II glacial outwash and
retransported hillslope deposits on the south side of Toolik Lake: (from top of
hill) SWT-7, 8, 9, and 10.
2. East-facing toposequence of slope that includes Itkillik I and Itkillik
glacial till and retransported hillslope deposits on the south side of Toolik
Lake: SWT-18, 19, 20, 21, 22, 24, and 77.
3. South-facing toposequence on Itkillik II till and retransported
hillslope deposits on the west side of Toolik Lake: SWT-46, 45, 44, 41, 40, 43,
39, 42, 38, and 37. These are in mixed positions on stone-stripes and inter-
stripe sites. Plots 38 and 37 are in a colluvial basin at the base of the hill.
4. North-facing toposequence on Itkillik II till and retransported
hillslope deposits: SWT-48, 47, 49, 50, 51, 52, 53, 54 and 81. Plot SWT 48 is
on a ground- squirrel mound, and most of the sequence is through a deep
snowbed.
5. Water-track transect on the south side of Toolik Lake: SWT-80, 32, 35,
75, 78, 27, 79, 36, 73, 74, 64. Plots SWT-80, 35, 74, and 64 are on frost
scars.
The remaining plots were located around Toolik Lake to sample the diversity
of vegetation types of the region (Figure 1, Table 2).
Sampling methods
Plot size, species cover estimation, and photographs
The plots have no fixed size because our main objective was to obtain
a complete species list for each relief.
Photographs were taken of each plot (see Appendix). Usually photos
were taken of (1) the general site, (2) close-up of the vegetation, and (3)
closeup of the soil.
Site factors
The site of each plot was described according to the variables listed
in Table 3 plus measurements of thaw depth, estimates of cover of bare soil,
rocks, and the major plant growth forms. These data are summarized in Table 4.
Soils
Field sampling
Soil pits were dug adjacent to the plots and described and
classified according to the U.S. soil taxonomy [Soil Survey Staff, 1975]. Soil
samples were collected from each horizon and air dried in the laboratory. Bulk
density and soil moisture samples were taken from the sides of the soil pits or
from large soil plugs for the wet soils using a 240-ml soil can.
Laboratory analysis
Laboratory analyses were conducted at the Colorado State
University Soil Testing Laboratory, Fort Collins. The laboratory's routine
analysis was run on all samples [pH (saturated paste); NO3 (KCl extract); P, K,
Zn, Fe, Cu, Mn (NH4HCO3-DTPA extract); lime estimate, texture estimate (by
hand); and organic matter (Walkley-Black or ash method). Selected samples were
analyzed for cation exchange capacity (C.E.C.); percentage gravel; particle size
(hydrometer method), CaCO3 equivalent; Ca, Mg, Na, K (NH4OAc extract); and soil
moisture retention (field capacity at 1/3 BAR and permanent wilting point at 15
BAR). These methods are described in Page et al. (1982) and Klute (1986). The
soils data are in Table 5.
Vegetation
A large area surrounding each plot marker was searched until no new
species were encountered. Estimates of vegetation cover used the Braun-Blanquet
cover-abundance scale (r = rare; + = common but less than 1% cover; 1 = 1-5%; 2
= 6-25%; 3 = 25-50%; 4 = 51-75%; 5= 76-100%). Cover-abundance values are
relatively broad subjective classes, and were determined by estimating cover
within the general area of the stake. Voucher collections were made for all
vascular plants, bryophytes, and lichens occurring in the plot. Vascular plants
were verified by Dr. Dave Murray, University of Alaska Herbarium. Bryophytes
were verified by Dr. Dale Vitt, University of Alberta. Lichens were verified by
Dr. Joanne Flock at the University of Colorado Herbarium. Table 6 contains the
raw species data.

Acknowledgments
This work was funded by the Department of Energy's R4D (Response, Resistance,
and Resilience to, and Recovery from Disturbance in arctic ecosystems)
(Grant No. DE-FG02-84ER60242.A006). Curt Westburg, Nancy Auerbach, and
Marilyn Walker assisted in the field. Liz Arnold, Diane Andrews, Nan Lederer,
Leanne Lestak, and Diane Lorenz assisted with the preparation of this report.

Notes: The tables and figure can be found in the full report which is available online
at http://arcss.colorado.edu/data/arcss.html.

Reference Citations: Klute, A. 1986. Methods of soil analysis, Part 1. Physical and
mineralogical methods. Agronomy Series, No. 9, American Society of
Agronomy, Inc.. and Soil Science Society of American, Inc.
Madison, WI, 1188 pp.
Mueller-Dombois, D. And H. Ellenberg. 1974. Aims and methods of
vegetation ecology. New York: John Wiley and Sons, 547 pp.
Page, A.L., R.H. Miller, and D.R. Keeney (Eds.) 1982. Methods of soil
analysis, Part 2. Chemical and microbiological properties. Agronomy
Series, No. 9, American Society of Agronomy, Inc.. and Soil Science
Society of American, Inc. Madison, WI, 1159 pp.
Soil Survey Staff. 1974. Soil taxonomy of the National Cooperative
Soil Survey. Soil Conservation Service, U.S. Department of Agriculture,
754 pp.
Walker, D.A., N.D. Lederer, and M.D. Walker. 1987. Permanent vegetation plots:
site factors, soil physical and chemical properties, and plant species cover.
Data report for R4D Program, U.S. Department of Energy.
Westhoff V. and E. van der Maarel. 1978. The Braun-Blanquet approach. In:
Whittaker, R.H. (Ed.) Classification of plant communities.
Boston: Junk, pp. 617-726.