Research
Central Theme of my Research Program
My program is best described as evolutionary ecology and conservation biology of amphibians and reptiles. I use reptiles and amphibians as study systems at the community and landscape level. I draw heavily from the fields of community ecology, ecological morphology, physiological ecology, foraging ecology, and simulation modeling to address the general questions, “What are mechanisms influencing the fit between organism and environment?”, and “How do community-level processes influence species persistence and distribution of species across the landscape?” This program addresses various conservation issues, for example, habitat requirements of single species, determinants of local and regional diversity, or mechanisms determining the fate of invasive and native species.
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Facilities
My lab is set up as a functional ecology lab where we conduct performance trials and experiments to infer mechanisms that are presumably important in the field. Space is divided into office space for students and flexible space for any sort of experiment using animals brought in from the field. For example, we studied burying performance of sand dune lizards, heating/cooling rates of an ontogenetic series of alligator snapping turtles, and locomotion, vision, and hydrodynamics on aquatic snakes. We also have a GIS station, many computers, a couple of old 4WD vehicles, all sorts of gear for fieldwork, and lots of camping gear.
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Current Projects
Conservation Biology and Ecology of Tupinambis Lizards
(Collaborators: Lucy Aquino, Margarita Mieres, Andrew Noss, Rosa Leny Cuellar, Rossy Montaño, Florencio Mendoza)
A large part of my research on the conservation biology and ecology of Tupinambis lizards involves studying the ecological interactions between local people and the lizards they use for food and income.Tupinambis lizards are among the most extensively traded reptile species in the world. Importantly, thousands of rural and indigenous people depend on tegus for subsistence and income. My interdisciplinary approach stresses the importance of local people and has contributed enormously to the success of the research program as a conservation model. The major policy implementation of this research was creating a legally binding harvest monitoring programs permanently funded by a tax system in Argentina and Paraguay. In Paraguay, Tupinambis lizards are the only managed wildlife species in the country. We are implementing the Tupinambis research program in Bolivia. I am very pleased that my research has been applied in 3 countries. The Tupinambis research program, and how it relates to people in developing countries, is summarized in papers in Conservation Biology, American Zoologist, Interciencia (in Spanish), Journal of Wildlife Management, and a book chapter in Neotropical Wildlife Use and Conservation, U. Chicago Press.
Ecology, Management, and Conservation of the Sand Dune Lizard (Sceloporus arenicolus)
(Collaborators: Charles Painter, Laura Laurencio, Mike Sears, Lauren Chan, Nicole Smolensky, Mike Hill)
Sceloporus arenicolus is endemic to the Mescalero Sands Ecosystem of eastern New Mexico and adjacent Texas. Sand dune lizards are habitat specialists at several spatial scales. Within the limits of their geographical range, sand dune lizards have an extremely strong affinity for bowl-shaped depressions in active dune complexes referred to as sand dune blowouts. They prefer relatively large blowouts, and select microhabitat within a given blowout. Within their geographic range, the presence of the lizards is also associated with composition of the sand; they only occur at sites with relatively coarse sand. I am taking a landscape ecology approach to understand this hierarchy of distribution and persistence of the species across the landscape at multiple scales. We study microhabitat selection and movements of individual lizards at very small scales, determinants of presence and absence at sites and regions, and population genetic patterns throughout the range of the species.
Population and Landscape Ecology of the American Alligator (Alligator mississippiensis)
(Collaborators: Kenneth J. Lodrigue, Amanda Subalusky, Wade Ryberg)
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Recent Projects
Rattlesnake Commercialization
(collaborators: Charles Painter)
Fitzgerald and Painter. 2000. Wildlife Society Bulletin. 28(1): 235-253. Rattlesnakes are
commercially exploited to supply an international trade in skins, meat,gall
bladders, and curios. Five species are used in 8 states: western diamondback
rattlesnakes (Crotalus atrox) in Texas, Oklahoma, and New Mexico;
eastern diamondback rattlesnakes (C. adamanteus) in Alabama, Florida,
and Georgia; prairie rattlesnakes (C. viridis) in Kansas, Texas,
Oklahoma, and New Mexico; and timber rattlesnakes (C. horridus) in
Pennsylvania, Georgia, Alabama, and Florida. Blacktail rattlesnakes (C.
molossus) occasionally appear in the trade in New Mexico and Texas. The
trade is linked to rattlesnake, roundups, which are economically important
to local communities. We estimated that 15% of the western diamondback and
eastern diamondback rattlesnakes entering the trade originate from roundups.
In the 1990s, probably < 125,000 rattlesnakes of all species entered the
trade yearly. Analyses of long~term data from 3 rattlesnake roundups showed
variable trends in rate of take, number of hunters, and pounds of
snakes/hunter. Analysis of the take of western diamondback rattlesnakes from
1959 to 1997 at the roundup at Sweetwater, Texas, showed no long-term
trends, but was characterized by extreme variability. Body size (snout-vent
length [SVL] and mass) and sex ratios of hunted western diamondback
rattlesnakes varied significantly by region and through time. These
differences were probably due more to geographic and temporal variation than
to the effects of hunting. Rattlesnake harvests of all species were
malebiased, and a few hunters collected the majority of the take. A model of
the economic impacts of imposing size restrictions on rattlesnake harvests
showed that hunters earn 19% more money when restricting take to
rattlesnakes >90 cm SVL (size at maturity of most females) whereas profit to
the industry increased 6%. Size limits below 90 cm SVL would minimally
impact total take; restricting take to rattlesnakes> 90 cm SVL would reduce
number of immature females by almost 50%. Rattlesnake species differ in
susceptibility to overexploitation, and research on life-history variation
of rattlesnakes should be an important management priority. Information also
is needed on local versus regional impacts of hunting, and monitoring
information is needed for the entire trade. Rattlesnakes are traded alive,
and issues relating to the treatment of live rattlesnakes need to be
considered when developing management plans for North American rattlesnakes.
Herpetology at Texas A&M ۰ TCWC ۰ Wildlife and Fisheries Sciences ۰ Ecology and Evolutionary Biology Program ۰ Texas A&M University