The overall goal of the Jornada Basin LTER (JRN) program is to quantify the key factors and processes that control ecosystem dynamics and biotic patterns in Chihuahuan Desert landscapes. These landscapes are representative of many arid and semiarid ecosystems of the world where dramatic changes in vegetation structure and ecosystem processes have occurred over the past several centuries. These changes in ecosystem state are often interpreted as “desertification”, the broad-scale conversion of perennial grasslands to dominance by xerophytic woody plants and the associated loss of soils and biological resources, including biodiversity. The JRN LTER has been investigating desertification processes since 1982.
The profession of range science in the United States has its roots in the closing decades of the nineteenth century, when widespread overgrazing and severe droughts resulted in acute episodes of livestock mortality, accelerated soil erosion, and a deviant loss of native forage plants across much of the western United States. The crisis was worst in the Southwest—western Texas, New Mexico, and Arizona—and beginning in the 1890s the US Department of Agriculture sent a handful of special agents to the region to assess the damages, study the causes, and identify potential remedies. Among the institutional outcomes of these early assessments and reports were large experimental ranges, beginning with the Santa Rita Experimental Range south of Tucson, Arizona, in 1903, and followed in 1912 by the Great Basin Experimental Range in Utah and the Jornada Experimental Range (The Jornada) in south-central New Mexico.
The Jornada Experimental Range has served as a field research laboratory since its establishment in 1912. The creation of the International Biological Program (IBP) provided the impetus for an ecosystem framework for research. The Jornada Basin was the location for the desert-grassland site within IBP. As the IBP dissolved in the late 1970s, the Long-term Ecological Research (LTER) program emerged in the 1980s as its successor. The LTER, in its second decade, had five core research efforts: (1) pattern and control of primary production; (2) spatial and temporal distribution of populations selected to represent trophic structure; (3) pattern and control of organic matter accumulation in surface layers and sediments; (4) pattern of inorganic inputs and movements of nutrients through soils, groundwater, and surface waters; and (5) pattern and frequency of disturbances. Research in these core areas provided a basis for modeling at the JRN over the years.