University of Texas at El Paso DigitalCommons@UTEP Open Access Theses & Dissertations 2012-01-01 Spatial Ecology Of The rT ans-Pecos Rat Snake (bogertophis Subocularis) In The hiC huahuan Desert Of Trans-Pecos Texas Arturo Rocha University of Texas at El Paso, [email protected] Follow this and additional works at: https://digitalcommons.utep.edu/open_etd Part of the Biology Commons, Ecology and Evolutionary Biology Commons, and the Zoology Commons Recommended Citation Rocha, Arturo, "Spatial Ecology Of The rT ans-Pecos Rat Snake (bogertophis Subocularis) In The hiC huahuan Desert Of Trans-Pecos Texas" (2012). Open Access Theses & Dissertations. 2175. https://digitalcommons.utep.edu/open_etd/2175 This is brought to you for free and open access by DigitalCommons@UTEP. It has been accepted for inclusion in Open Access Theses & Dissertations by an authorized administrator of DigitalCommons@UTEP. For more information, please contact [email protected]. SPATIAL ECOLOGY OF THE TRANS-PECOS RAT SNAKE (BOGERTOPHIS SUBOCULARIS) IN THE CHIHUAHUAN DESERT OF TRANS-PECOS TEXAS ARTURO ROCHA Department of Biological Sciences APPROVED: _____________________________ Jerry D. Johnson, Ph.D., Chair _____________________________ Carl S. Lieb, Ph.D. _____________________________ John C. Walton, Ph.D. _____________________________ Benjamin C. Flores, Ph.D. Interim Dean of the Graduate School i SPATIAL ECOLOGY OF THE TRANS-PECOS RAT SNAKE (BOGERTOPHIS SUBOCULARIS) IN THE CHIHUAHUAN DESERT OF TRANS-PECOS TEXAS By ARTURO ROCHA, B.S. THESIS Presented to the faculty of the Graduate School of The University of Texas at El Paso in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Department of Biological Sciences THE UNIVERSITY OF TEXAS AT EL PASO August 2012 ii ACKNOWLEDGEMENTS Funding by the National Science Foundation (FSML) for the facilities at Indio Mountains Research Station (IMRS) provided the main core of funding through grants, making this study possible. Professors and committee members Carl S. Lieb, and John C. Walton provided valuable input for this study, as well as relevant literature for this project. I wish to thank Dominic I. Lannutti, a Professor at El Paso Community College (EPCC) and Dr. William P. Mackay at UTEP, who first introduced me to field ecological studies. My advisor, Dr. Jerry D. Johnson (“Dr. J”) provided all the necessary resources both in the field, as well as in the input in the study and the final versions of this thesis. Dr. Johnson is also responsible for the maintaining the IMRS facilities, overseeing the research station and providing the direction to ongoing research activities. His dedication to IMRS has led to numerous publications and collaborations with other researchers who utilized the research station. Dr. Johnson also cooked meals at IMRS, allowing myself and other graduate students to continue with their research with minimal distractions, as wells as preparing and assistance for the required protocols, proposal, and presentations to numerous events relating to this study. For all this, I am grateful. When I first took the Field Biology course with Dr. Johnson, I met Dr. Vicente Mata-Silva. During that course, I volunteered to help radiotrack Crotalus lepidus on IMRS that was part of his dissertation study at the time. It was in these initial steps that led me to achieve my B. S. in iii Biological Sciences, and subsequently working on my graduate studies. Dr. Mata-Silva provided valuable advice, as well as words of encouragement throughout the duration of this study. I witnessed his gradual journey from Ph. D. student, to candidate, to full realization of the title “Doctor”, although he always put in the time to assist myself (and others) in our research. I thank you as a colleague, and as a friend for all your help. There are individuals I wish to thank that I met throughout the duration of my research out at IMRS. Prior to my graduate studies and the initial phases of this study, these individuals befriended me to make the transition of a new environment flow more easily. As colleagues, they also shared a similar interest in herpetology and science in general, and numerous entertaining stories we’ve shared at IMRS. Steve “Chalupa” Dilks, whom taught us the “two rock method” while out in the field. Those out in the field will be the only ones who understand what that means. Luis “El Napoleón” Miranda, showed me around IMRS on my first visits. Also there is a tale of his at IMRS that is humorous, that only a few will know about, but it involves a mine and apparel. Anthony “Crazy Tony” Gandara and I initially assisted Vicente in the beginning phases of his study. How a person hiking through rugged terrain, while explaining the relationship between memes and genes, fall into a thicket of Agaves, get up, and continue with the conversation as if nothing happened is beyond words. Hector “Bionic Leg” Riveroll Jr. served as an unofficial “tutor”, or “guru” to many students, also joined us in radiotracking snakes on several occasions. In the latter phases of this study, individuals such as William “Hey Art, check this out” D. Lukefahr (whose rants are entertaining as well as engaging), Julia “Butterfingers” Alva, Ross “Hey y’all!”Couvillon, and Geoffrey “Now hold on!”Wiseman also provided companionship while at IMRS. iv All these individuals and myself helped one another out at IMRS, be it from preparing food, changing tires, driving in flash floods, fixing the roads (to this day I still don’t know which rocks Dr. J was referring to) after the rains, and in times of extremes (hot and cold), looked out for one another. Thank you guys! I am thankful to Dr. Rebecca Escamilla (who graduated in the spring of 2012) whom assisted me in GIS maps and related applications. She kindly allowed me to use her GIS map of IMRS for use in the analysis of field data. To my parents, Norma Rocha and Alejandro Rocha, who always supported my studies and provided a pillar of support. I could not have accomplished this project without them. My brothers Alex, Abraham, and sister Raquel were also supportive in all aspects. Abraham accompanied me once at IMRS during the study. Although it possibly raised more questions than answers, his presence there provided a bridge to my family in exactly what was I doing “out there”. In all, to my family, thank you for your love and encouragement. This study would have been far more difficult without the use of the ATVs out at IMRS, which would have meant hiking even longer distances than those experienced during the study. I thank Department of Biology professors Dr. Craig. E. Tweedie as well as Dr. Johnson for the vehicles. I thank all the students from the UTEP Field Biology and Maymester courses whom assisted me and were also fascinated with the nature of my project. To all herpetologists, especially those who’ve radiotracked snakes, their efforts have motivated me throughout the study. v Finally, I want to thank the UTEP Department of Biological Sciences and the Graduate School in which supported trips to national and international meetings. This allowed me to give oral and poster presentations on the spatial ecology of the Trans-Pecos Rat Snake. vi ABSTRACT The Trans-Pecos Rat Snake (Bogertophis subocularis) is a medium to large rat snake that occurs from south-central New Mexico, south-central Texas, down into the north-central and northeastern states of Mexico. There is paucity in the ecology of B. subocularis to date. Some North American colubrid snakes, such as Thamnophis sirtalis, are the most represented species in thermal ecology and life history studies in all reptiles. There is nothing known on the winter ecological aspects of this species, and very little information regarding its overall ecology. The goal of this study is to determine home range, movement patterns, habitats and utilization of microhabitats, and the overwintering characteristics of the Trans-Pecos Rat Snake (Bogertophis subocularis) in the Chihuahuan Desert on the Indio Mountains Research Station (IMRS) located in Hudspeth County, in far west Texas. From the summers of 2009 – 2011, six adult snakes were captured, monitored, and radiotracked in their active seasons (May – October) and winter seasons (November – March) (two males and three females). Average home ranges occupied by individuals was large (58.8 ha), and ranged from 20.9 to 123.6 ha. Snakes emerged from their overwintering sites in late April to early May, and returned to those sites in late October to early November. By sex, mean home ranges were 46.5 ha (n = 3) for females and 77.2 ha (n = 2) for males. Snakes occupied a small core areas (50 % kernel) (average 0.000005 ha), in which on average, males occupied slightly large core areas (0.000006 ha) than females (0.000004 ha). Daily movement for all snakes averaged 17.3 m/d, with females moving at a greater rate (18.4 m/d) than males (14 m/d). There was no significance between daily movement rates by month, vii however, daily movement rates between sexes was statistically significant. The greatest mean distance by month snakes traveled was May, followed by July, June August, September and October. Bogertophis subocularis was observed in four habitats on IMRS, and snakes were mostly associated rocky slope habitats (n = 74, 43 %), followed by alluvial flats (n= 43, 25 %), alluvial slopes (n= 32, 18%), and arroyo habitats (n = 24, 14 %). Snakes were found in five identified microhabitats, found under shrubs (36 %), followed by under rocks (20 %), and in burrows (20 %), with lesser occurrences under plant litter (14 %), and in crevices (10 %). The composition of microhabitats showed that snakes selected microhabitats in which vegetation was the most represented (41 %), followed by rocks (30 %), plant litter (20 %), and gravel (9 %).