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. 

Increasing land fragmentation, mostly caused by urban sprawl and “leap-frog’ developments, is a major concern in many rapidly growing metropolitan cities of the US. Land fragmentation affects biodiversity and ecosystem processes, as portions of the landscape become isolated without connecting corridors and this, in turn, can change ecological structure and function. This cross-site comparative study, a joint-collaboration of several LTER sites (i.e.

Grass to shrubland conversions have been widely reported in drylands world wide, but remain poorly understood. Knowledge of ecosystem spatial properties and the environmental constraints underlying landscape pattern is crucial to determining why shrublands have replaced grasslands in some areas and not others as well as predicting where such transitions may be most likely to occur in the future.

Wind and Water erosion are two dominant, interrelated transport processes that influence the dynamics of arid and semi-arid ecosystems. Complex interactions between wind and water erosion and transport events vary across different landscape units, exhibiting varying degrees of dominance; thereby, affecting soil types, topography, and the movement of soil parent material over spatial and temporal scales. Historic and prehistoric interactions of these erosion events between different landform units are poorly documented in the stratigraphic record.

Shrubs have displaced grasses throughout much of the world’s arid and semiarid lands (drylands) over the past century. In the Chihuahuan Desert in southern New Mexico, the conversion of black gramma grasslands to mesquite shrublands over the past 100 years has been well documented. The extent to which this displacement of grasses by shrubs has altered leaf litter quality and the spatial distribution of litter inputs and thus nutrient turn over via decomposition is unknown.

 Future changes in climate are likely to strongly affect plant physiological and growth parameters, and thus potentially influence competitive interactions among plants. We used rainout shelters and sprinklers to test the influence of changes in precipitation on aboveground physiological parameters and belowground growth of honey mesquite (Prosopis glandulosa) and black grama (Bouteloua eriopoda) at the Jornada Basin LTER. In this area of the northern Chihuahuan Desert, mesquite and other woody plants have encroached into former desert grasslands over the past 150 years.

Patch-scale connectivity is frequently cited as a significant factor controlling redistribution of water, organic matter and nutrients in many arid and semi-arid ecosystems. The ‘leakiness’ of these systems has been cited as an indicator of degradation. Methods to limit or modify soil loss and redistribution are included in many restoration strategies.

Decomposition is a fundamental driver of biogeochemical cycling that dictates nutrient availability, carbon storage, and community composition. Although mechanistic models of decomposition dynamics have been successfully applied to many different systems, predicting decomposition in drylands has remained problematic due to a poor understanding of the driving variables. A recent study in the Sonoran Desert found a strong positive relationship between decomposition rates and the amount of soil deposited onto litter, which varied by a factor of six as a function of microsite vegetation cover.