Movimentação e uso do ambiente por subadultos de Podocnemis expansa (Testudines: Podocnemididae) na Reserva Biológica do Rio Trombetas, Pará

Abstract

Understanding animal movement patterns is one of the most important aspects of wildlife conservation and management. Among the Amazonian chelonians, the giant South american river turtle (Podocnemis expansa) is the most threatened podocnemid in the biome. The movement pattern of this specie is poorly understood, especially for sub-adults. The main objective of this study was to analyze and describe the use of space by subadults of P. expansa in the Trombetas River Biological Reserve (REBIO), Pará. Between October/2010 and September/2011, the movements of eight females and one subadult male using VHF radiotelemetry were studied. The home range estimated with the Minimum Convex Polygon (MCP) technique ranged from 1.91 to 50.25 km2 (14.46±15.5), while with the Fixed Kernel with 95% of locations (KF95%) it ranged from 0.19 to 19.17 km2 (3.7±6). Movement rates were positively affected by the size of individuals and negatively by the water level of the river. The monitoring showed that the subadults occupy lake systems and lateral channels to the main course of the Trombetas River. During the flood periods, the individuals remained inside the igapó forest, probably feeding on fruit and seeds. During the ebb and dry periods, as the availability of flooded forest decreases, they move to deeper parts of perennial lakes and the main course of the Trombetas River, close to the spawning beaches, including localizations during the basking behavior between adult females. All the techniques traditionally used to analyze movements were appropriate and each one explained some of the movement behavior. Displacement of some individuals from Trombetas REBIO to traditional areas of quilombolas represents a degree of threat to the age/size classes analyzed, and must be considered in future studies aiming at the conservation and sustainable management of the largest freshwater turtle of the South America.