Impact of small mammal disturbances on water and sediment yields in the Jornada Basin, southern New Mexico

TitleImpact of small mammal disturbances on water and sediment yields in the Jornada Basin, southern New Mexico
Publication TypeThesis
Year of Publication1999
AuthorsNeave M
Number of Pages243
Date Published1999
UniversitySUNY at Buffalo
CityBuffalo, NY
Thesis TypePh.D. Dissertationpp
Accession NumberJRN00277
Call Number00722
Keywordsdissertation, dissertations, disturbance, rodent, hydrology,, hydrology, grassland, hydrology, rainfall simulation, hydrology, sediment transport, hydrology, shrubland, hydrology, surface runoff, hydrology,sediment yield, rodent, hydrology, runoff, rodent effects, sediment yield, theses, thesis
AbstractThis study examines water and sediment movement on a bajada in the Jornada Basin, New Mexico. Forty-five rainfall simulation experiments were conducted on 1 m2 and 2 m2 runoff plots in grassland, degraded grassland, and shrubland communities. Within the shrubland community separate experiments were conducted in shrub and intershrub environments. Regression analyses indicate that for a 30-min rainfall at approximately 130 mm h1, water yields on these environments are negatively related to the percentage of ground covered by vegetation and/or litter. In the degraded grassland and intershrub environments, sediment concentration is positively correlated with the average diameter of small mammal disturbances, suggesting that animal digging is an important factor controlling rates of erosion in these environments. Sediment concentration is not correlated with any surface property in the grassland or shrub environments. An analysis of water yields and sediment concentrations at 5-min intervals during the 30-min simulated rainfall experiments reveals that the influence of the above-mentioned factors on runoff and erosion is established 10 to 15-min into a rainfall event. A comparison among the different communities indicates that the shrubland (incorporating both shrub and intershrub environments) produces higher water and sediment yields than either the grassland or the degraded grassland. This finding has important implications for the historical replacement of grassland by shrubland. ... Thus the impact of small mammals on the erosion, transport, and redeposition of sediment in the study area depends not only on the amount of activity by the animals but also on the average distance to a rill. Because intense animal activity and short interrill flow paths occur together only in the shrubland, it is evident that this is the community where degradation of the soil by small mammals has been greatest.