Browsing by Autor "Lee A. Fitzgerald"

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Activity and Ranging Behavior of the Red Tegu Lizard Tupinambis rufescens in the Bolivian Chaco
(2013) Rossy Montaño; Rosa Leny Cuéllar; Lee A. Fitzgerald; Florencio Mendoza; Filemón Soria; Christine V. Fiorello; Sharon L. Deem; Andrew J. Noss
In the Bolivian Chaco the red tegu lizard Tupinambis rufescens is the most important reptile among indigenous communities for subsistence, commercial and traditional medicinal purposes. Information on the home range and habits of Tupinambis rufescens in an area free from hunting pressure is an important basis for a management plan for this species in the Chaco, to ensure that commercial hunting programs will not threaten the species' long-term survival in the region. We used surgically implanted radio transmitters (nine individuals) and temperature dataloggers (five individuals) over a two-year period to describe home ranges, burrow use, as well as daily and seasonal activity patterns at a field camp next to the Kaa-Iya del Gran Chaco National Park. Red tegus occupy home ranges of 16–54 ha, with maximum distances travelled of 700–1500 m. In order to survive the strongly seasonal climate of the dry Chaco they strictly limit their daily and seasonal activity, and rely heavily on burrows. They are diurnal, with an activity peak from 11:00–12:00 h. Their activity period is September—April, with some variation among individuals and among years. They remain inactive in a single underground burrow during the May—August estivation months, and use multiple burrows and shelters for nighttime refuges during the active months. The dataloggers provide extremely detailed body temperature information describing daily and seasonal activity patterns, but surgical implantation should be undertaken by specialized veterinarians.
Chelonoidis carbonaria (Testudines: Testudinidae) Activity Patterns and Burrow use in the Bolivian Chaco
(2013) A. J. Noss; Rossy R. Montaño F.; Fernando Soria; Sharon L. Deem; Christine V. Fiorello; Lee A. Fitzgerald
In the Bolivian Chaco, the tortoise Chelonoidis carbonaria is an important reptile for indigenous people for subsistence purposes and in traditional medicine. This article describes research on seasonal activity, daily activity, and burrow use for the species at two long-term research camps in the Kaa-Iya del Gran Chaco National Park. The principal research method is the use of internal and external temperature dataloggers in 15 individuals over a two-year period. Tortoises reduce their activity in the dry season, and are not active when air temperatures are below 20°C or above 37°C, though they can be active outside burrows at any time of year. Body temperature varies from 4°C in winter (monthly average of minimum daily temperatures) to 38°C in summer (monthly average of maximum daily temperatures). The instantaneous difference between body and environmental temperature could be as great as -23°C or 12°C, but the monthly average was between -2°C and 4°C. Tortoises rely principally on shelters including fallen trees, dense bromeliad ground cover, and leaf mulch; but also use armadillo burrows and rock crevices. They use multiple shelters / burrows over time, occasionally sharing shelters with other individuals. Burrow use is important both in cold periods as well as in hot and dry periods. The dataloggers provided extremely detailed data on body and environmental temperature, but the implantation caused problems in several individuals and the procedure may need modifications.
Ranging patterns by the red-footed tortoise - Geochelone carbonaria (Testudines: Testudinidae) - in the Bolivian Chaco
(2013) Rossy R. Montaño F.; Erika Cuéllar; Lee A. Fitzgerald; Filemón Soria; Florencio Mendoza; Romoaldo Peña; Telmo Dosapey; Sharon L. Deem; Andrew J. Noss
In the Bolivian Chaco, the tortoise Geochelone carbonaria is an important reptile to indigenous people for subsistence purposes and in traditional medicine. In Bolivia the species is considered near threatened, while observations suggest it is less abundant near communities and cattle ranches. However, understanding of its biology and ecology is limited. As part of a landscape conservation program with indigenous land and wildlife management, this article describes research on ranging patterns for the species at two long-term research camps in the Kaa-Iya del Gran Chaco National Park. The principal research method is radio-telemetry with 15 individuals over a two-year period. The tortoises occupy home ranges of 50-600 ha, with males using ranges three times larger than females. Individual home ranges overlap, up to 96% between pairs of monitored individuals, with multiple individual ranges overlapping simultaneously, while many males and females shift their ranges between wet and dry seasons. The relatively large ranges for an animal of this size in the Chaco, combined with shifting ranges across seasons, even in protected areas, means that conservation of red-footed tortoises within human-impacted landscapes will require provision of key resources that include appropriate food, water, and shelter where these become scarce. Alternatively, indigenous territories and ranches will need to set aside communal and private reserves exceeding 1,000 ha in order to maintain tortoise populations on their lands.