Submitted to: Society for Range Management Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2007
Publication Date: 2/9/2007
Citation: Hansen, N., Herrick, J.E., Abbott, L., Peters, D.C., Parker, D. 2007. Using GIS to study the past and present of a northern Chihuahuan Desert playa [abstract]. Society for Range Management, 60th Annual Meeting and Trade Show, February 9-16, 2007, Reno/Sparks, Nevada. Paper No. 179. 2007 CDROM.
Technical Abstract: The encroachment of mesquite (Prosopis glandulos Torr.) and other desert shrubs into the desert grasslands of the northern Chihuahuan Desert is commonly associated with increased rates of soil erosion. The processes associated with vegetation shifts are still poorly understood. One such example of vegetation shift is the replacement of tobosa (Pleuraphis mutica Buckely) grasslands by mesquite dunelands on the Red Lake playa, an ephemeral lake on the USDA-ARS Jornada Experimental Range in south central New Mexico, USA. The objective of this project was to describe grass-shrubland transitions for vegetation patches based on soil characteristics and spatial context. We used aerial photos from 1942 and 1973 and a digital orthophoto quarter quadrangle from 1996 to define changes in the mesquite-dominated area since 1942. We used the 1996 photos to compare GIS-based mesquite canopy intercept measurements with line-point and canopy intercept measurements completed in 2005. We then used a QuickBird satellite image from 2004 to identify current vegetation community patches based on vegetation type, soil reflectance, and the spatial distribution of plants and bare ground within each patch. Plots were then established in the field within these patches to characterize the soils and vegetation of the site and create highly-detailed soil and vegetation maps of the site. After the initial characterization, the field data and 2004 satellite image were compared against the older imagery and past vegetation and soil maps to identify areas requiring more intensive soil and vegetation measurements. We plan to use these data to identify relationships between various soil properties and vegetation community composition and structure. This information will be used on patterns and processes to propose changes to state-and-trainsition models correlated with soils in this area.