Project Title: Changing Land Use Patterns along the United States-Mexican Border: Effects on Ecosystem Structure and Climate Feedbacks

SCERP Project Number: NR98-2

Principal Investigator: Jeffrey Klopatek

Task Manager's affiliation: Arizona State University

Goal: The purpose of this study is to examine specific paired sites along the western Arizona-Mexico border between Nogales and Yuma to examine the effects of human activity on the local ecosystems. Goals are to: 1) quantify ecosystem structural properties through field and laboratory measurements of vegetation and soil parameters; 2) measure the climatological and energy balance differences at these sites; 3) determine the relationship between the ecosystem properties and climate; 4) describe and model the feedback processes; 5) scale the site data up to the level of the landscape to cover the entire border area in question with remote sensing and a GIS database; 6) describe trends in ecological changes along this border region during the last 30 years; and 7) discuss the potential long-term ecosystem consequences of the present condition and predicted trends.

Direct and indirect human activities have been shown to reduce ecosystem productivity and increase desertification in the deserts and grasslands along the United States-Mexican border. This deterioration of ecosystems can result in a significant decline of species diversity, loss of vegetative cover, reduction of soil organic matter and soil moisture, increase in particulate pollution and significant changes in biogeochemical cycles. The ecosystem deterioration further results in a change in climate that produces a complex set of feedbacks that accelerates the desertification process and may affect changes in regional climate. The research will result in greater understanding of the interactions of climate and vegetation in dryland areas, aid in assessing potential future human-induced impacts, and assist in mitigating ecosystem deterioration in this region.

Activities have included: bibliography compilation, site selection, meteorological measurements, vegetation analysis, soil sampling, soil analysis, climatological database, remote sensing image analysis, remote sensing vegetation map, remote sensing GIS database, ecosystem climate correlation, and simulation model run and refinement. This research has shown annual temperature increases along the border, on both the Mexican and U.S. sides, of 0.07 and 0.05 degrees Celsius, respectively.

Phase I of the project began in September of 1996 and concluded mid 1998. Phase II is in progress.

Last updated 5/6/99