Site history & management
Land use at Jornada has contrasting livestock grazing histories (including ungrazed lands), dating back to 1902, which are representative of the pervasive land use in desert-southwest wildlands. Historical accounts of the region report significant changes in vegetation starting in the late 1800s coincident with the expansion of livestock grazing. By 1912, sufficiently dramatic changes lead area scientists and private landowners to convince the U.S. government to set aside Public Domain Lands for the Jornada Range Reserve for the purpose of scientific investigation on shrub invasion and subsequent loss of forage grasses. Much of this early research focused on quantifying utilization levels for forage species, developing livestock production strategies to deal with drought, and developing methods for shrub control and grass recovery. Exclosures were constructed and long-term plots were established throughout the range to monitor the continued expansion of shrubs across the landscape. Over the decades, numerous trials of various remediation approaches were implemented, from manual and mechanical shrub removal to herbicide application to construction of terraces or other means of redirecting surface flow of runoff.
Vegetation cover at Jornada is dominated by Desert Scrub and Grassland, which together represent ~ 90% of the Domain. Throughout southern New Mexico, where the Jornada research site is located, large upland areas that were formerly dominated by perennial grasses, including black grama (Bouteloua eriopoda) and mesa dropseed (Sporobolus flexuosus), have been replaced by desert shrubland species, in particular creosote bush (Larrea tridentata) and honey mesquite (Prosopis glandulosa). Native desert shrubs and non-native grasses have a well-documented history of increase and opportunities exist to compare invaded and uninvaded areas.