|James, Aline -|
|Tweedie, Craig -|
Submitted to: Ecological Society of America (ESA)
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2010
Publication Date: N/A
Technical Abstract: Chihuahuan desert 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. Our study addresses a question that is central to the dynamics of arid ecosystems: How spatial and temporal variation in ecosystem properties related to desertification? Under what conditions do fine-scale processes cascade to affect larger spatial scales, and under what conditions do broad-scale drivers constrain processes to influence system dynamics?. We hypothesize that spatial and temporal variations in ecosystem dynamics is the result of patch structure interacting with transport vectors (i.e. turbulence, water) and environmental drivers (i.e. temperature, precipitation, CO2) to influence cross-scale resource redistribution, these interactions feedback to patch structure to cause cascading effects on ecosystem good and services. A new GIS-based decision tool was developed to choose our study site, located on the southwest section of the Jornada Experimental Range (JER). The tool allows users to input geospatial data, weight each criterion according to their priorities and/ or other factors that may affect the accuracy of their instrumentation and subsequently identify sites that best match their criteria. We parameterized this decision tool to identify optimal location in creosote mesquite shrubland on the JER that best meet the instrumental limitations of an Ameriflux standardized eddy covariance tower. Following ground thrusting of five sites we established an extended Open Path Eddy Covariance Tower. The automation of data collection process has been developed. Data is collected remotely on a near-real time basis, screened and flagged automatically for QA/QC purposes, then archive into a database where data are accessed through a web interface.