This data set contains information regarding vegetation structure at sites in grama grassland and both creosote and mesquite shrubland habitats at the Sevilleta NWR. This information was collected at randomly selected sites throughout the refuge. Each site is within 100 meters of one of the 22 road-based transects(20 in 2008) that were used to carry out coyote scat surveys during three seasons (spring, summer and fall) in 2009 (see "Coyote scat surveys in grassland and shrubland sites at the Sevilleta NWR, spring, summer and fall 2009" data set). Data was collected within at total of 22 circular vegetation plots (40 in 2008), each of which is 30m in diameter. Each plot was surveyed a total of three times, specifically in: April (spring), July (summer), and October (fall) 2009. Variables were selected based on their relevance to patterns of coyote habitat use, as well as their utility in calibrating Landsat images of the study site and the likelihood that they would vary seasonally. Measured variables include: average percent live woody vegetation cover, average percent live grass cover, average percent live forb cover, and average woody plant height. Information on woody plant species with individuals greater than 0.5 m in height is also presented.
Vegetation surveys were carried out at grassland and shrubland sites located throughout the Sevilleta NWR. In 2008, two plot locations were randomly elected for each of twenty road based scat transects that were surveyed during the same field season. Vegetation plot location was determined by randomly selecting the following: a distance from the beginning of each mile long, road-based scat transect; side of the road (left or right); and a distance from the road (30-100m).
One of the two plots associated with each of the 20 scat transects surveyed in 2008 was randomly selected and surveyed in each of the three seasons in which scat surveys were conducted in 2009. Two new vegetation plots, one for each of two new scat transects, were also surveyed in 2009.
Each vegetation plot was circular with a 30m diameter intended to match the spatial scale of a Landsat satellite image pixel. In 2008, each of 40 plots was surveyed once between July 30th and August 20th, 2008. At each plot, measurements were collected along 4 x 15m line intercept transects, one per cardinal direction, and in 5 x 1m^2 quadrats located at random distances and angles from the plot center. In 2009, half of these plots and two new ones were each surveyd three times, once in each of the following three months: April, July, October. At each plot, measurements were collected along 4 x 15m line intercept transects, one per cardinal direction.
The coordinates of the center of each vegetation plot were determined using a GPS unit. In 2008, percent woody vegetation cover was measured, to the nearest 0.1m, along the 4 x 15m line intercept transects described in the sampling design section. This data was later combined to obtain estimates of percent woody cover for 2 x 30m transects that passed through the plot center and were perpendicular to one another such that one ran north-south and the other ran east-west. An attempt was made to measure percent cover only for live woody plants with a height of 0.5 m or greater. A plant was considered to be alive if it had green leaves on some part of it. The one exception to this rule was Gutierrezia sarothrae, for which percent cover was assessed for both plants with green leaves and plants with dead flowers but no green leaves. Each woody plant that crossed the line intercept transects was identified to species and, for each plant with a height of 0.5m or greater, the height was recorded and two perpendicular axes of the plant were measured. 5 interplant distances were measured from the first woody plant (0.5m or taller) that was encountered along each of the 4 line intercept transects in a plot. These distances were measured to the 5 closest woody plants that were also at least 0.5m tall and were within the plot and therefore represent nearest neighbor distances. When no woody plants were encountered along the line intercept transects, measurements were made from the woody plant closest to the first 1m^2 quadrat (described in sampling design section). Fewer than 5 distances were measured when there were fewer than 6 woody plants found within the plot boundaries.
Measurements of percent grass cover were made in the 5 x 1m^2 quadrats described in the sampling design section. For each quadrat, the dominant grass, defined as the grass with the highest percent cover, was identified to genus and a small sample was collected. Two grass genera were recorded in cases where the two grasses had similar values for percent cover. A small sample of each woody plant species (excluding cholla and other cactus species) found within the plot was also collected. In 2009, percent live woody vegetation, grass and forb cover was measured, to the nearest 0.1m, along the 4 x 15m line intercept transects described in the sampling design section. This data was later combined to obtain estimates of percent woody, grass and forb cover for 2 x 30m transects that passed through the plot center and were perpendicular to one another such that one ran north-south and the other ran east-west. A plant was considered to be "live" if there were green leaves or stalks. For a given plant that intersected a line intercept transect, if only part of the plant had green leaves or stalks, then only that part was measured and included in the calculation of percent live vegetation cover. Each woody plant that crossed the line intercept transects was identified to species and, for each plant with a height of 0.5m or greater, the height was measured to the nearest 0.1m and recorded. As a result, a list of woody plant species with individuals of a height greater than or equal to 0.5m that crossed the line intercept transects is presented for each plot. A small sample of the dominant woody plant species (excluding cholla and other cactus species) and one of the dominant grass species found within the plot was collected. Dominance was determined based on vegetation data collected in 2008. In particular, dominance was defined as follows: woody plant species with the highest value for percent cover within the plot; grass species with the highest percentage cover in at least one of 5 1m^2 quadrats that was surveyed in each plot.
All plant samples were dried for 24 hours at 60 degrees Celsius and, in future, will be prepared and run through a stable carbon isotope analysis.
Data were recorded in the field and entered into a spreadsheet in Excel. Extraneous information, for example information on woody plants less than 0.5m in height, was removed. No automated or quantitative data quality checks were performed.
Additional Information on the personnel associated with the Data Collection / Data Processing
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