Home range and genetics of Texas horned lizards (Phrynosoma cornutum) in two small towns in south Texas

Characteristics of urbanization such as roads, buildings, exotic species and vegetative homogenization can create patches of habitat surrounded by poor-quality, unfavorable areas. This inhibits movement, which in turn restricts gene flow. We used radio-telemetry and genetic markers to study the movement patterns in Texas horned lizards (Phrynosoma cornutum) in the neighboring towns of Kenedy and Karnes City, Texas. Individuals had small home ranges and rarely moved across roads. Nuclear and mitochondrial DNA markers revealed low genetic diversity in these towns and another urban site at Tinker AFB in Oklahoma compared to a larger natural area in Texas. There was significant genetic structure within town on either side of large roads as well as significant genetic structure between towns. These data suggest that movement is curtailed within and between these towns which may have long-term negative impacts such as inbreeding depression and a lowered ability to adapt to changing conditions.