Recent research has unveiled the potential consequences of constructing new hydroelectric power plants in Brazil’s South region on the habitat of the Williams’ side-necked turtle, scientifically known as Phrynops williamsi. This study indicates that more than 30% of the turtle’s habitat could be affected by such developments. This particular species exclusively resides in areas encompassing the Atlantic Rainforest and the adjacent Pampa biome, situated along Brazil’s borders with Uruguay and Argentina. Alarmingly, the International Union for Conservation of Nature (IUCN) has classified this species as “Vulnerable,” signifying a high risk of extinction.
Published in the Journal of Applied Ecology, the research was conducted by a team of scientists hailing from various Brazilian states, including Goiás, São Paulo, Rio Grande do Sul, Mato Grosso, Mato Grosso do Sul, Santa Catarina, and Paraná.
André Luis Regolin, a professor and researcher at the Federal University of Goiás (UFG) and the primary author of the study, expressed, “Our investigation is groundbreaking in its comprehensive examination of the repercussions of hydropower developments on this species. The findings hold the potential to inform strategies for mitigating the adverse impacts of hydroelectric expansion on freshwater turtles. Furthermore, this methodology can be adapted for studying other species that face threats from electricity sector projects.”
The study revealed that hydropower developments and the associated reservoirs overlap with regions highly suitable for the species, covering only 20% of its distribution. The situation is expected to deteriorate with the planned construction of small hydropower plants (SHPs) in the near future. The extent of habitat affected by SHPs will nearly match that impacted by large projects, which currently pose the greatest threat to the species.
Reservoirs generated by these projects inundate the turtles’ habitats, erasing the essential rapids they rely upon. As they attempt to seek suitable areas, many turtles are obstructed by dams, hindering their migration. The study underscores the increasing scarcity and fragmentation of highly suitable areas due to the growing number of hydropower developments.
The primary methodology employed by the researchers involved correlating potential turtle habitat data with georeferenced information on hydropower plants obtained from the National Electricity Agency (ANEEL). This analysis covered a total of 687 hydropower developments, with 406 in operation, 48 under construction, and 233 in the planning phase.
While the assessment of the species’ conservation status partly validated earlier studies, it indicated that the risk of extinction had been underestimated. Currently categorized as “Data Deficient” in Brazil due to insufficient information, the study suggests that it should be classified as “Vulnerable” due to the estimated loss of 30% of its distribution range. In Paraguay, Uruguay, and Argentina, where the species has a very limited range, it should be designated as “Endangered” according to the study’s findings.
One of the key reasons these freshwater turtles have been overlooked in prior assessments of hydropower development impacts is the tendency for reptile sampling methods to concentrate on terrestrial species. The researchers hope that their study will inform decisions regarding future projects. André Luis Regolin concluded, “We have unveiled the cumulative impact pattern of hydropower developments on the species’ distribution, which is a pressing concern. Our discoveries hold significant relevance for decisions concerning hydroelectric expansion, yet there remains a critical need for further research to address the knowledge gaps related to P. williamsi. Substantial investment in cutting-edge research is essential to formulating concrete conservation proposals for this species.”