Thursday, August 7, 2008

PS 67-159: Landscape variability in soil and vegetation response to 70-year-old restoration treatments

Noemi Baquera1, Jeff E. Herrick2, H.C. Monger1, Albert Rango3, Heather L. Throop1, and Michael C. Duniway2. (1) New Mexico State University, (2) USDA Agricultural Research Service, (3) Jornada Experimental Range

Background/Question/Methods

During the 1930’s the Civilian Conservation Corps implemented a number of landscape restoration projects, most of which were abandoned in the early 1940’s. Although many restoration projects failed, several projects had a lasting effect on the landscape and can be used to study the long term effects of restoration treatments. Restoration treatments including soil berms were created in Las Cruces, New Mexico in the early 1930’s.  Soil berms are soil barriers laid across the contours of the landscape to slow water movement resulting in water ponding and increased water infiltration.  Water ponding initiates a cyclical feedback system where the establishment of vegetation (grasses) promotes soil stability and soil stability increases vegetation establishment.  Soil berms mimic naturally banded vegetation.  The objective of this project was to assess landscape variability in soil and vegetation response to soil berms in order to guide future restoration efforts in the Chihuahuan Desert, and better understand the ecological processes associated with soil and vegetation recovery.  GIS analysis was carried out using a 1936 to 2005 chronosequence of aerial photographs. Ground measurements were completed to supplement the 2005 GIS analysis.

Results/Conclusions

Berms were found on three different soil types described by the Desert Soil Project as; Algerita Complex (Coarse-loamy), Soledad-Onite Complex (Loamy-skeletal / Coarse-loamy), and Hachita Pinaleno soils (Loamy-skeletal).  Preliminary GIS results supported by field observations indicate a greater vegetation response to the berms located on the Soledad-Onite complex.  Berms located on Loamy-skeletal soils demonstrated the lowest response.  Restoration treatments are site specific and require extensive analysis of site characteristics such as soil type, vegetation, annual precipitation, or slope.  Soil berms are an effective method to slow water movement across the landscape. However, it may not be an appropriate treatment for all soils.  Future research should investigate the soil and vegetation response of soil berms on other soil types, and attempt to identify the specific soil and topographic characteristics that are associated with positive responses to this type of treatment.