Date of Award


Degree Name

Doctor of Philosophy


Biological Sciences


Jerry Johnson


Traditional lizard pitfall traps were modified to allow organisms to escape, while collecting valuable ecological data. Modified camera traps were capable of detecting the same species as traditional traps in a semi-arid environment, without posing the associated mortality risks. Pitfall-camera traps were used to sample the activity of the Side-blotched Lizard (Uta stansburiana) and the Southwestern Fence Lizard (Sceloporus cowlesi) in an urban wetland during four continuous years. Evaluations on activity pattern and the activity overlap between the two species revealed extensive overlap, with minor but significant seasonal shifts mediating coexistence. Traps were also effective at detecting other reptiles, invertebrates, and rodents. The same method was effective at discerning the activity patterns of closely related and potentially competing, sympatric whiptail lizards (Aspidoscelis). The capability of the improved sampling method was evaluated by surveying four separate sites in the northern Chihuahuan Desert where the hybrid Common Checkered Whiptail (A. tesselata) and its progenitor, the Marbled Whiptail (A. marmorata) coexist. The relative diversity was the highest at the Indio Mountains Research Station, Culberson County, Texas. Regardless, no differences were observed in the activity pattern of the whiptail species studied, except for a significant seasonal shift exhibited by the unisexual, Common Checkered Whiptail (A. tesselata), possibly explained by an increase in overlap within sites with high activity detected on individuals of the Marbled Whiptail (A. marmorata).




Recieved from ProQuest

File Size

108 p.

File Format


Rights Holder

Guillermo Alvarez