Dams and amazon turtles conservation in Tocantins River, Brazil

In this study we discuss the large hydroelectric dams, built in cascade, in the Tocantins River, Legal Amazon, Brazil and its effects on the fauna of turtles .The analysis was based on the experience of the authors who watched the environmental changes associated with these projects in the Tocantins River for more than a decade. Some of the most important species are Podocnemis expansa and Podocnemis unifilis. The Tocantins River has seven large hydroelectric plants in operation and other 4 dams in different phases of licensing, and also 35 Small Hydroelectric Power Plants. The loss of feeding and spawning areas of turtles, by the cascading dams contributed to the natural systems disconnection. A combination of flooded riparian vegetation and changes in flood regimes affects the populations that depend on the terrestrial and aquatic environments material in their diet. Reproduction in amazon turtles is related to precipitation, temperature and water level of rivers. Considering the reservoir regions, flooding may occur on the reproductive areas or can happen the permanent exposure of nesting sites, modifying, for example, granulometric aspects of the soil, affecting hatching success and the sex ratio of the hatchlings. Considering turtles, P. expansa stands out as a migratory species, the dams in series can have serious implications in this behavior. The biggest challenge is to reconsider the model of power generation in Brazil. In order to make progress, a real interaction is necessary, thinking about the conservation of natural resources as something holistic, without separating natural and social systems.