|RACHAL, DAVID - New Mexico State University|
|OKIN, GREG - University Of California|
|Herrick, Jeffrey - Jeff|
Submitted to: Wildland Shrub Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2012
Publication Date: N/A
Technical Abstract: Semi-arid grassland and savanna communities in many parts of the world have been displaced by woody shrubs. In the Jornada Basin of southern New Mexico, the displacement of perennial grasslands is well documented beginning in 1858. As shrubs invade semi-arid perennial grasslands, the length, number, and arrangement of connected bare patches increase which creates transport corridors. Increased growth and coalscence of these connected pathways over time cann result in a nonlinear increase in soil loss and redistribution by wind and water. Implementing remediation strategies that disrupt the growth of these connected transport pathways is a potential mitigation strategy that can lessen the harmful effects of shrub encroachment. Small-scale manipulations were conducted in two high sediment transport environments positioned in shrublands, and located on a wind erosion dominated landform (basin floor) and a water erosion dominated landform (bajada). Sediment retention structures were deployed in highly eroded unvegetated gaps. Fallout radionuclide tracers were used to understand how these structures modify the lateral movement of sediment by water during the monsoon and by wind in the windy season. Fallout radionuclide inventories indicate that retention structures are more efficient in modifying soil redistribution by wind compared with water.