Population Structure and Dynamics of the Midget Faded Rattlesnake

Research Task: 8327CNJ.7.0
Task Manager: Sara Oyler-McCance

Very little is known about the ecology of Midget Faded Rattlesnakes (Crotalus viridis concolor), considered rare throughout their range. Midget Faded Rattlesnakes exist in very small, isolated groups centered around den sites with few (1–25) individuals, and seasonal movements may be only a few hundred meters. Such natural history traits make these rattlesnakes a sensitive species vulnerable to various human impacts. In addition, the construction of Flaming Gorge Reservoir over 50 years ago divided the population in half and forced them to higher ground. This study investigated the population structure and dynamics of Midget Faded Rattlesnakes, using genetic analyses of microsatellite DNA markers in the lab and radio telemetry in the field. FORT scientists have analyzed the genetic structure of the population as a whole along with localized characteristics of subpopulations around the reservoir. They found significant levels of genetic structure among populations and showed that the Flaming Gorge Reservoir and associated waterways did not pose significant barriers to movement. Additionally, they found that the most genetically distinct populations were those farthest north and the most susceptible to potential impact from human activity.

 For more information contact Sara Oyler-McCance