Data set ID:
This is data for perennial plant vegetation canopy cover measured from all SMES study plots, fall 1995. The purpose of this data is to provide ground-truth data for comparison with low-level aerial photographs of each study plot. Three, 29 meter lines were measured along three of six rows of the permanent vegetation measurement quadrats. Each line was measured at 10cm resolution for intercepts of perennial plant live canopy cover, and for bare ground. 10cm resolution is comparable to the resolution of the aerial photos. All plants were identified to the species level. These line-intercept measurements are taken once every ten years, at the same time that low-level aerial photographs are taken. These data will be compared to both decadal air photos, and annual measures of vegetation from one-meter2 quadrats on each plot to provide information on vegetation change over time relative to the various animal exclosure treatments.
field data sheets
100 meter measuring tapes were attached to the steel re-bar posts marking vegetation quads 1, 3, and 5 on each study plot. The measuring tapes were extended south to the re-bar posts marking quads 36, 34, and 32. Data were recorded for all intercepts of live perennial plant canopy foliage, and for bare ground. The start and end points for each intercept were recorded to the nearest 10 cm on the measuring tape. Intercepts less than 5 cm were ignored, and intercepts between 5 and 10 cm were recorded to the nearest 10 cm. Intercept measurements were only recorded for perennial plant species, and for bare soil. Annual plants and dead perennial plants were ignored. The data were entered in the field on to micro-cassette tape recorders. The taped recorded data were then entered on to MS Excel spreadsheets. A macro statement was used to subtract each observed intercept end measure from the start measure, to produce an intercept measure for each observation. Those data were then converted to space-formatted text file s, and combined as one file.
SAS program will be used to analyze data
The Jornada LTER site is located at the US Department of Agriculture, Agricultural Research Service, Jornada Experimental Range in southern New Mexico (Figure 1). The Jornada is located at 32 north latitude, and the grasslands and shrublands are at about 1,300 meters elevation. The grassland site is one kilometer west of the IBPE grassland site, and the creosotebush site is three kilometers southeast of the lower trailer. The Sevilleta LTER site is located at the US Fish and Wildlife Service, Sevilleta National Wildlife Refuge in central New Mexico (Figure 1). The Sevilleta is located at 34 north latitude, and the grasslands and shrublands are at about 1,550 meters in elevation. The Mapimi Biosphere Reserve is located in the south-central Chihuahuan Desert in the northeastern portion of the state of Durango, Mexico (Figure 1). The Mapimi site is located at 27 north latitude, and the creosotebush shrublands are at 1,100 meters elevation. The Mapimi research site is primarily creosotebush shrubland with mesquite. Tabosa (Hilaria mutica) grasslands occur in the bottoms of basins.
Every 10 years.