Ranging patterns by the red-footed tortoise - Geochelone carbonaria (Testudines: Testudinidae) - in the Bolivian Chaco

Abstract

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.