Current Research:
Guadalupe Bass: Hybridization between the Guadalupe bass and the non-native smallmouth bass was first documented in the 1970's and was later determined to be introgressive hybridization. I am conducting a range-wide survey of the introgressive status of the Guadalupe bass to determine its conservation status. Additionally, I will examine the phylogeographic structure among pure Guadalupe bass as it relates to the historical movement of Guadalupe bass through geological processes such as stream captures. I am also interested in the potential effects of possibly reduced genetic variability associated with restoration efforts on individual-levels resource specialization.
Past Research:
Blanco River: I examined the spatial and temporal trends in the fish assemblage of the Blanco River, Texas and evaluated the effects of low-head dams on local fish assemblages. The Blanco River is home to several fish species that are endemic to the Guadalupe River drainage and to Edwards Plateau region of Texas. Many of these species face threats from overpumping of groundwater (e.g. Guadalupe roundnose minnow), altered hydrologic regimes, and exotic species (e.g. hybridization of Guadalupe bass with smallmouth bass). This study was conducted in conjunction with others at Texas State University as well as The Nature Conservancy to construct a framework through which monitoring of aquatic resources within the watershed can be accomplished.
Gray Redhorse: The gray redhorse is found in Texas from the Brazos river through the Rio Grande as well as in south eastern New Mexico and north eastern Mexico. The gray redhorse has declined in portions of its range (particularly in the Pecos River). I examined the reproductive ecology and diet of the gray redhorse in the Blanco River and Canyon Lake, Texas. Temporal patterns in gonadosomatic index indicated that gray redhorse spawns over two distinct periods during spring and likely spawns multiple clutches during each period. Gray redhorse are benthic invertivores and diets differed significantly between riverine and reservoir habitats, likely reflecting differential availability of prey items. Although habitat degradation is of concern for gray redhorse, it has persisted in systems with altered hydrologic regimes. Declines in the Pecos river might reflect reduced water quality rather than hydrologic regime alteration.