Rescuing and recovering a Darwin’s frog stronghold

The Endangered Darwin’s frog (Rhinoderma darwinii) is threatened by the amphibia chytrid fungus Batrachochytrium dendrobatidis (Bd). In 2023 researchers detected the invasion of Bd into the southernmost remote area of Tantauco Park, where it caused dramatic declines in what had been the largest known R. darwinii sub-populations. In response a collaborative effort was launched, led by the NGO Ranita de Darwin and the Zoological Society of London, bringing together 24 governmental, non-profit, and private organisations from Chile, Argentina, Germany, and the United Kingdom as the “Alianza Tantauco”, with a common goal: restoring the Darwin’s frog populations within Tantauco Park to their pre-Bd fungus state. In October 2024 86 frogs were rescued and safely transport to captive breeding facilities - 53 to ZSL London Zoo, and 33 to the Universidad de Concepción. One field enclosure has been built as an experimental approach to exclude syntopic amphibians and other potential Bd reservoirs from the population of 50 Darwin's frogs inside the enclosure. A second enclosure will be completed by October 2025 and monitoring continues throughout the region. A spatially explicit individual-based model describing the demography and chytrid infection dynamics in Darwin’s frogs has been developed and will serve as a central component of the decision-analytical framework to be constructed in late 2025 and throughout 2026.