Ecohydrology

The effects of western juniper (Juniperus occidentalis) control on vegetation and topsoil water interactions were studied at the watershed-scale. Seasonal differences in topsoil water content, as affected by vegetation structure and soil texture, were determined for a pair of previously treated and untreated watersheds. A watershed-scale characterization of vegetation canopy cover and soil texture was completed to determine the driving factors influencing soil water content fluctuations throughout dry and wet seasons for one year (2014-2015). Total canopy cover, and more specifically functional group cover, was the dominant variable affecting soil water content over time. Increases in perennial grass cover were positively correlated with changes in soil water content during the wettest months. Increases in juniper cover were negatively correlated with soil water content. Soil particle analysis of samples collected from the top five inches profile fell mostly under sandy loam textural class. A few areas within each watershed showed relatively higher clay content. A geospatial analysis of soil water content and clay content showed corresponding areas of high clay and high soil water content across watersheds. Maps derived from the geospatial analysis illustrate the progression from dry to wet season, as well as the influence of topographical features on soil water content.