U.S. Geological Survey home page

Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

TITLE: Rangeland C03-031 S15% G14% DESCRIPT


SAMPLE_ID: C03-031

PLANT_TYPE: Mixed rangeland shrubs, grasses, and forbs



COLLECTION_LOCALITY: Catnip Mountain, in the Sheldon-Hart Mountain National Wildlife Refuge Complex, is located in northwestern Nevada, approximately 55 miles southeast of Lakeview, Oregon

COLLECTION_LATITUDE: 41 deg. 50.669 min. N

COLLECTION_LONGITUDE: 119 deg. 22.240 min. W




This spectrum is the average reflectance for an area of rangeland covered by mixed shrubs, grasses and forbs as detailed in this description of site number C03-031.

Collection Date
The reflectance data were collected on 22-Jun-2003.

Site Vegetation Description
The total vegetation cover on this site was 48%. The following table shows the percent cover by cover class:

Cover Category, Sub-Category                Cover (%)
_____________________________      ____________________________
Vegetation, Total Cover                  48
Vegetation, Tree                            0
Vegetation, Shrub                          15
Vegetation, Grass                          14
Vegetation, Forb                           19
Non-vegetation, Total Cover              52
Non-vegetation, Litter                     10
Non-vegetation, Bare                       42
Non-vegetation, Other                       0
_____________________________      ____________________________

The following table shows the cover by shrub species in the site (for shrubs with greater than 2% cover):

Shrub Species                            Cover (%)    Avg. Height (cm)
_____________________________________  ____________  __________________
Artemisia tridentata                       14               35
_____________________________________  ____________  __________________

The following table shows the cover by grass species in the site (for grasses with greater than 2% cover):

Grass Species                             Cover (%)
_____________________________________  _____________
Poa secunda                                 8
Pseudoroegneria spicata                     3
_____________________________________  _____________

The following table shows the cover by forb species in the site (for forbs with greater than 2% cover):

Forb Species                             Cover (%)
_____________________________________  _____________
Castilleja applegatei                      7
Lupinus argenteus                          2
_____________________________________  _____________

Field Observations
The plot is on the margin of an unburned patch of sage. Many blooming paintbrush and wild onions are scattered throughout the site. Not much bare soil is exposed.

Site Orientation
The mean elevation of the site is 2130 m (6987 ft). The mean slope of the site is 19%, with a Southwest aspect of 220 degrees.

Site Burn History
Part of the area of this plot has recently burned (since 1996).

Site Location, Dimensions, and Vegetation Sampling
The center coordinates of this rangeland plot are 41 deg. 50.669 min. N, 119 deg. 22.240 min. W (datum is NAD83). The diameter of this circular vegetation plot was 15.2 meters. Within this plot, four subplots of 0.5 meter diameter were established 5 meters from the center at the four cardinal directions (north, east, south and west). Within these subplots, grass and forb species were identified and associated percent cover of each were visually estimated. Litter cover and the percent area of bare ground were also visually estimated. For each shrub in the larger plot, the species was identified, the lateral dimensions were measured, and the height was measured. The cover of trees, shrubs, grasses, forbs, litter and bare ground were calculated from the full plot and subplot measurements. Field identifications of Tetradymia canescens (winterfat) were inconsistent between the 2003 and 2004 field seasons. In 2003, some shrubs were identified as Chrysothamnus nauseosus (gray rabbitbrush) and Krascheninnikovia lanata (winterfat). Later, it was determined that some of these shrubs were incorrectly identified and it was decided to label them all as Tetradymia canescens.

Spectral Measurement Procedures
This spectrum is the average of 53 measurements made throughout site C03-031. These spectra were collected using an ASD Full Range Field Pro spectrometer in reflectance mode, relative to a Spectralon reference panel. While walking through the site, the fiber optic cable was pointed at nadir (straight down) at approximately shoulder height. The instrument was programmed to record 6 second averages of reflectance while moving through the site (thus, each recorded spectrum was an average of 60 individual measurements). These recorded spectra were examined for artifacts due to low signal:noise, detector offsets and atmospheric contamination. Those spectra with large artifacts were not included in further processing. An average of the remaining 53 spectra was computed. This average spectrum was converted to absolute reflectance by multiplying by the reflectance spectrum of the Spectralon reference panel. The following channels were deleted (set to a value of -1.23e+34) from the spectrum because of remaining artifacts: 1-6, 410-413, 576-592, 761-801, 1006-1051, 1441-1591, 2111-2151 (corresponding to the wavelength ranges of 0.350-0.355, 0.759-0.762, 0.925-0.941, 1.110-1.150, 1.355-1.400, 1.790-1.940, and 2.460-2.510 microns).

Catnip Mountain General Description
The Catnip Mountain study area is located in northwestern Nevada, 55 miles southeast of Lakeview, Oregon, in the "Sheldon-Hart Mountain National Wildlife Refuge Complex," which is managed by the U.S. Fish and Wildlife Service. The approximate center of the study area is 41.8584 degrees North latitude and 119.3533 degrees West longitude. The vegetation cover of the study site consists of areas of decadent or dead bitterbrush (Purshia tridentata) stands with islands of old mountain mahogany (Cercocarpus ledifolius) scattered near the ridges. Mountain big sagebrush (Artemisia tridentata) dominates the low elevation areas with grasses and forbs mixed with mountain big sagebrush. Little sagebrush (Artemisia arbuscula) dominates the cover of the ridges. Elevations of the site are about 6,000 to 7,000 feet (1,830 to 2,135 m).

Project Background
This site was measured as part of a cooperative U.S. Geological Survey and Bureau of Land Management project funded by the Joint Fire Science Program.

IMAGE_OF_SAMPLE: Photo of site facing north Photo of site facing east Photo of site facing south Photo of site facing west



Amount Weight
Percent, %
COMPOSITION: Water: %(of fresh weight)
COMPOSITION: Total_Chlorophyll: %(of fresh weight)
COMPOSITION: Chlorophyll_A: %(of fresh weight)
COMPOSITION: Chlorophyll_B: %(of fresh weight)
COMPOSITION: Nitrogen: %(of dry weight)
COMPOSITION: Lignin: %(of dry weight)
COMPOSITION: Cellulose: %(of dry weight)








SPECTRAL_PURITY: 1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib06a r 31470 g.s.=