Three exclosure sites each with sixteen 21.3 x 21.3 m plots were established in 1938/39 to evaluate the effects of lagomorph exclusion and shrub removal in a creosotebush dominated community.
The study sites, developed by Ken Valentine, were placed on the Jornada Experimental Range at the following locations: 1) outside the southeast corner of the Gravelly Ridges Artificial Revegetation Enclosure, 2) about one half mile southwest of Parker Tank, and 3) inside the Moisture Conservation Plots Enclosure about .15 mile east of the Dona Ana Revegetation Enclosure. Major dominant shrubs (creosotebush, mesquite, and tarbush) were individually severed at ground level and removed by hand in 1939, 1947, 1956, 1960, 1967, 1989, 1995, and 2001. Lagomorphs were excluded with poultry wire fencing in 1939 and integrity of fences is maintained. The objective of the original study was perennial grass responses to shrub removal, lagomorph exclusion, furrowing (shallow, hand raked furrows designed to trap surface water), and seeding (broadcast application of seeds of native perennials). Furrowing and seeding treatments were short lived and not repeated or maintained. All plots were sampled prior to initial treatment applications in 1938/39 and immediately following all subsequent shrub removal events. Each plot was divided into east and west halves and 14 randomly located 10.65 m line intercept transects were sampled for shrub canopy cover and perennial grass basal cover.