Biodiversity & Ecology

English

Abstract: Measures of plant cover and density are available from 130 permanent transect locations on the 21,000 ha Santa Rita Experimental Range. This long-term research area stretches across the western alluvial skirt of the Santa Rita Mountains, about 50 km south of Tucson, Arizona (31º50’ N, 110º53’ W). Elevation increases from about 900 to 1,450 m, with a corresponding increase in annual precipitation from 275 to 450 mm (fig. 1). Transects were established between 1956 and 1972 and were re-measured every year from 1956-1966, and every three years from 1972-2009 (except 1987). Transects are 30.4 m long and 0.31 m wide, and line intercept measured on the long axis provides an estimate of grass basal cover and shrub canopy cover, and counts of plants rooted in the 9.28 m2 area provide estimates of plant density. All previous measurements and UTM coordinates are available on the Santa Rita web site (http://ag.arizona.edu/srer). This report describes the available content in the vegetation-plot database "Santa Rita Experimental Range Long Term Transect Database" (GIVD ID NA-US-005).