Defining boundaries across borders: a case study extending a major land resource area into Mexico

The Chihuahuan and Sonoran Deserts occupy significant areas on both sides of the border and demonstrate similar climate, geology, soil and water resources, and vegetation. MLRA 41 is a very diverse ecological area in the transition zone between the Sonoran and Chihuahuan Deserts, consisting of a series of isolated mountain chains and arid river basins. We used geographic information science (GIS) and field work to extend MLRA 41, Southeastern Arizona Basin and Range, from southeastern Arizona and southwestern New Mexico into northeastern Sonora and Chihuahua. This is a proposed method to link NRCS ecological sites with the Comisión Técnico Consultiva de Coeficientes de Agostadero (COTECOCA-Technical Commission for Stocking Rates) Sitios de Productividad Forrajera (Forage Production Sites). Precipitation, temperature, vegetation, soils, and elevation data were collected to compare the NRCS MLRA characteristics with that of the available data for Mexico. The result of this analysis is an updated boundary. This new boundary of MLRA 41 does not extend as far west or south as the previous boundary. This boundary should still be considered tentative, but will allow land managers and investigators in Mexico to take advantage of the existing contained in ecological site descriptions for MLRA 41