Dramatic decline and range contraction of the Endangered Patagonian frog Atelognathus patagonicus (Anura, Leptodactylidae)

摘要

The Endangered frog Atelognathus patagonicus is endemic to the Laguna Blanca wetland system, Patagonia, Argentina. This species has undergone a significant contraction of its original distribution, including loss of the main population from the largest lagoon, Blanca. The decline of A. patagonicus was first perceived in 1986 and was thought to be at least partially associated with the anthropogenic introduction of the perch Percichthys col-huapiensis for sport. To evaluate the potential impact of P. colhuapiensis on A. patagonicus we surveyed for both species in 28 lagoons, and found A. patagonicus present in 23. These lagoons represent, however, only a small percentage of the total wetland area. The presence of A. patagonicus was associated with lagoons characterized by absence of P. colhuapiensis and high abundance of macro-phytes. The most severe problem facing the remaining populations is in the many lagoons currently not protected by Laguna Blanca National Park. Conservation efforts need to focus on the prevention of fish introductions in the wetlands areas on private land. A project to restore A. patagonicus to Laguna Blanca, and educational programmes emphasizing the protection of Patagonian wetlands as reservoirs of regional biodiversity, are currently under development.