You are here:
SOIL MICROTOPOGRAPHY ON GRAZING GRADIENTS IN CHIHUAHUAN DESERT GRASSLANDS
Citation:
Nash, M S., E. Jackson, AND W G. Whitford. SOIL MICROTOPOGRAPHY ON GRAZING GRADIENTS IN CHIHUAHUAN DESERT GRASSLANDS. JOURNAL OF ARID ENVIRONMENTS 55(1):181-192, (2003).
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
We tested the hypothesis that one of the significant impacts of livestock in the creation of
piospheres centered on water points is the loss of soil microtopography. The size, height, and spatial distribution of micromounds and surrounding depressions were measured by a modified erosion bridge at three distances (50 m, 450 m, and 1050 rn) from water points in desert grassland pastures in the Jornada Basin, N. M.. Plots at 50 m had fewer n-iieromounds and the mounds were smaller than those recorded on the more distant plots. Microtopography of plots at 450 m from water was not significantly different from that recorded at 50rn. Microtopography of plots that were 1050 m frorn water points was significantly different from that of plots nearer water points. Loss of rnicrotopography from the impacts of livestock in piospheres exacerbates erosion processes and contributes to decertification.