Water Canal: a Deadly Trap for Patagonian Tortoises

ECHAVE, MARIA EUGENIA; KUBISCH, ERIKA

Simposio; 21th Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles; 2023

In the Patagonian region inhabits the Chaco Tortoise (Chelonoidis chilensis), the southernmost continental tortoise in the world. This species is considered vulnerable nationally and internationally. The species is subject to many threats in all their distribution, but in Rio Negro`s province, has special threats, as predation by dogs and wild boars, and, the most conspicuous one is the Pomona water canal, a 195 km long concrete-made canal that crosses the Patagonian plateau, supplying San Antonio Oeste and Las Grutas cities. We found high numbers of drowned individuals that had fallen into and died inside of the canal across the seasons, animals are attracted to the water, they fall and cannot come out again, due to their smooth, high and steep walls. Also, the canal would act as an ecological and physical barrier, preventing wildlife´s natural movements and dispersal. Our main goal was to determine the Pomona canal´s effect on the tortoise population, in order to reduce its negative impact. During December 2022 and February 2023 (summer season), 10 volunteers monitored the grid located at km 150, that filters garbage and plant debris, recording dead fauna and rescuing live animals. One hundred and twenty-five animals were extracted, including 39 Chaco tortoises. It is estimated that many animals were not detected, since the 68% of the days monitored the water level exceeded the grid, not fulfilling the containment function so the animals continued 16 km to a lagoon where it is difficult to detect them. The tortoises were the animals that resisted the most, however, most of them would have died if they had not been rescued in time. The number of deaths of native animals, many with some degree of threat, motivates us to intensify monitoring during the next season, along the entire canal in order to identify the most vulnerable sectors for fauna. Also, work will be done with the personnel of the company in charge of managing the canal and public officials to generate strategies to mitigate the impact of the canal on local fauna.