Photo of UAV at study site, photo by Carolina Medina-Nava.

Ecohydrology and Its Effects on Reseeding Techniques in the Green Valley, Brewster County, Texas

Carolina Medina-Nava, Bonnie J. Warnock, Mieke Titulaer, and Kevin Urbanczyk (Rio Grande Research Center)

Understanding the fate of rainwater is critical in semi-arid and desert systems, as water is most often the limiting factor in plant growth and distribution. When an ecosystem shifts from one dominant vegetation community to another, the soil water balance shifts. This shift is often created by decreases in plant material resulting in faster runoff due to lower water residence time on the soil surface, decreased soil infiltration due to loss of organic material and fibrous plant roots, and increased evaporation due to increased soil temperature.

The herbicide, Tebuthiuron has become a popular grassland restoration tool, but successful grass establishment is not equal on all soils. The objectives of this study were to (1) determine soil moisture and temperature differences among vegetation and soil types during a grassland restoration project in the Terlingua Creek watershed on the O2 Ranch, Brewster County, Texas; (2) develop a model to select and determine microtopography using high-resolution imagery from UAVs and soil wetness index estimates to select potential seeding microsites, and; (3) determine the success of different reseeding techniques (seed balls, seed balls covered with burlap, burlap tubes, seed broadcasting, and seed broadcasting covered with burlap) in different microsites (bare ground, nurse plants, and microtopographies) in the Chilicotal soil series after treatment with Tebuthiuron.

The results of this study will help future landowners to better understand ecohydrological factors such as soil moisture and temperature and to develop restoration plans based on science.