Re-establishment of an extinct local population of the Valcheta Frog, Pleurodema somuncurense, in a restored habitat in Patagonia, Argentina

Abstract

In March 2017 and March 2018, we reintroduced 196 and 50 individuals Valcheta frogs Pleurodema somuncurense, respectively (tadpoles and juveniles). The individuals were translocated from an ex situ colony to a restored habitat at the hot springs of the Valcheta stream (Rio Negro, Argentina). The aim was to re-establish a local population of this species that had gone extinct at this site. After the individuals were released, we monitored them using night visual encounters to register the number of individuals and other relevant records that suggested acclimatization (feeding, escaping and reproduction). In addition, we performed a Capture-Mark-Recapture study to estimate the density of the reintroduced population using POPAN models. By September 2018, the estimated density was 62 ± 27 SD in a stream area of 50 m2. This does not differ from density estimates of wild populations of the Valcheta Frog. Additionally, reproduction of reintroduced frogs was recorded in September 2018 and January 2019. Egg clutches, tadpoles and juveniles were all observed at the reintroduction site. These results suggest that the reintroduction of captive bred individuals to the wild might be an effective management action to restore local populations of this species that had gone extinct.