Hillslope soil movement in the oak savannas of the Southwestern Borderlands Region

Abstract

Oak woodlands and savannas comprise more than 31,000 square miles (80,290 square kilometers) in the southwestern United States and northern Mexico and provide various resources including forage for livestock, wildlife habitat, fuelwood, and recreational areas. Increased woody-plant encroachment into the more open savanna ecosystems has presented a problem to managers and ranchers concerned with maintaining these ecosystems with less overstory density. Prescribed fire has been proposed as a managerial tool to help control woody-plant encroachment and improve the production of forage. Concerns over the ramifications to other ecosystem attributes from the reintroduction of fire, however, have been raised. One concern is how soil erosion rates might be affected. This study examined erosion and deposition rates on a biannual basis for 12 watersheds in the oak savannas of the Southwestern Borderlands Region to provide an indication of soil movement on hillslopes to managers of these ecosystems. Rates were measured at the plot level and compared to plot characteristics before the watersheds were subjected to cool and warm season burns and an unplanned wildfire. Pre-treatment erosion and deposition rates, as well as the initial post-fire erosion and deposition rates after the bums, are reported in this study.

Citation

Kauffman, Aaron. 2009. Hillslope soil movement in the oak savannas of the Southwestern Borderlands Region. Tucson: University of Arizona. 74 p. Thesis.