A Comparison of Vegetation Responses to Grazing Yearlong, in the Growing Season, and in the Dormant Season on Low-Value Semidesert Grass-Shrub Ranges in Southern Arizona - Cover data for 1957-1966 and 1970



The file contains perennial grass basal cover and shrub foliar cover data collected for USFS Study FSRM 1706-09. A copy of the Study Plan may be downloaded at http://ag.arizona.edu/SRER/study09/study09.txt. Measurements were taken annually from 1957-1966 and in 1970 on 12 pairs of sample plots in each of 6 pastures. Each pair of plots was located at one of three distances from water and on one of two kinds of soil. Each pasture was subjected to one of three livestock grazing treatments. Pastures 3 and 5N were grazed during the winter dormant season (approximately November through April). Pastures 5S and 12B were grazed during the summer growing season (approximately May through October). Pastures 2N and 6B were grazed yearlong. Two permanent 100-ft. line transects were established at each plot location. One transect in each plot was a control, but all mesquite (Prosopis velutina) within 50 ft. of the other was killed. Cover was measured in autumn on each of the permanent line transects in units of 0.01 ft. Perennial grass was recorded as basal intercept; i.e., length of live root crown portion of tuft at ground level. Shrub cover was recorded as the entire live crown intercept excluding conspicuous openings or areas of dead crown. Sources of data were original field data sheets and a printout of previously digitized data. Taxa were recorded separately to the species level in most cases and sometimes to the genus level only. When measurements are entered for OTHERPG (unidentified perennial grass species) and OTHSHRUB (unidentified shrub species) the species/genera referred to are not consistent. In this study ARIS refers to the Aristida genus (specifically tall threeawns). A value of -9999 in a field means that no data were available because a reading was not made for that date. A value of -99 in a field means that the datum is unknown.
Date made available2005
PublisherKNB Data Repository

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