The Chihuahuan Desert, similar to many arid and semiarid ecosystems, has experienced dramatic changes in vegetation structure and ecosystem processes over the past 150 years. This “desertification” is manifested by the broad-scale expansion of unpalatable woody plants into perennial grasslands with associated loss of grasses and increase in soil degradation that compromise the ecosystem services provided to human populations.

Regime shifts from grasslands to shrublands in arid and semiarid ecosystems are thought to be irreversible, similar to state changes in other systems. We analyze long-term data from the Jornada Basin LTER site to determine if a directional change in climate provides an opportunity to reverse this conversion in the Chihuahuan Desert. We compare historical dynamics based on 140 years of landscape change (1858-1998) with 18 years (1990-2007) of detailed ecosystem responses under a variable climate to predict future responses under either a directional increase or decrease in rainfall.

High yielding perennial grasses, legumes, and grass/cereal hybrids are currently being investigated as potential alternative crops which could produce high yields of food or forage while also maintaining high levels of ecosystem services (lowered erosion, increased carbon sequestration, improved soil quality, and higher levels of pollinators and natural enemies as compared to annual systems). However, it is still unknown to what extent it will be possible to select perennial grasses and perennial grass/cereal hybrids for increased yield without jeopardizing the perennial life cycle.

Resource control in the western Pyrenees from 1800 to the present is addressed by reference to external factors: historical events; economic, technological and policy changes; and in the context of the “house system,” which functioned and continues to function as a control agent of environmental exploitation practices. The issue for the present is political, having to do with the conflict of legitimacy fed by the confusion that exists over the concept of the mountain: “free space” (high mountain zone) vs.

The Southwest is the incubator of the country’s fastest growing urban landscapes; relatively young socio-ecosystems of known origins but unknown fates. The region has long-served as a destination for the American dream of the fresh start, the new land; sunlit places far from East Coast stoicism and West Coast angst. Ironically, Thomas Jefferson’s humid zone ideal of an eternally expanding fee simple empire remains most robustly in force and uncontradicted in the deserts of the Southwest. Las Cruces, New Mexico is no exception.

Public lands in the desert Southwest have rich and complex human histories.  This poster presents data and analyses from an ongoing research project which is linking socio-economic and ecological dimensions for public lands grazing allotments.  The project uses public records to create a timeline of human events which may affect ecological outcomes. 

Both increases and decreases in diversity have been documented in urban areas, with suggested explanations ranging from species-productivity relationships to habitat fragmentation, introduced species, disturbance and pollution. For landscape planning and urban wildlife management, it is imperative to understand which processes act in determining diversity in urban habitats. For over ten years we have monitored arthropod communities with pitfall traps in the Central Arizona Phoenix area in residential areas and compared them to desert and desert remnant sites.

Large and complex watersheds, as result of complex topography, characterize the Mexican landscape. And although water for human consumption is becoming more limited as water demands increase, there is incomplete information on current and future water availability. As water resources become scarce, it is not clear how ecosystem services of economic critical ecosystems will be impacted due to limited water supply in Mexico. The objective of this project is to evaluate how ecosystem resiliency capacity is controlled by the hydrological connectivity in a variety of Mexican ecosystems.