A flagship for Austral temperate forest conservation: an action plan for Darwin's frogs brings key stakeholders together

Abstract

Darwin's frogs Rhinoderma darwinii and Rhinoderma rufum are the only known species of amphibians in which males brood their offspring in their vocal sacs. We propose these frogs as flagship species for the conservation of the Austral temperate forests of Chile and Argentina. This recommendation forms part of the vision of the Binational Conservation Strategy for Darwin's Frogs, which was launched in 2018. The strategy is a conservation initiative led by the IUCN SSC Amphibian Specialist Group, which in 2017 convened 30 governmental, non-profit and private organizations from Chile, Argentina and elsewhere. Darwin's frogs are iconic examples of the global amphibian conservation crisis: R. rufum is categorized as Critically Endangered (Possibly Extinct) on the IUCN Red List, and R. darwinii as Endangered. Here we articulate the conservation planning process that led to the development of the conservation strategy for these species and present its main findings and recommendations. Using an evidence-based approach, the Binational Conservation Strategy for Darwin's Frogs contains a comprehensive status review of Rhinoderma spp., including critical threat analyses, and proposes 39 prioritized conservation actions. Its goal is that by 2028, key information gaps on Rhinoderma spp. will be filled, the main threats to these species will be reduced, and financial, legal and societal support will have been achieved. The strategy is a multi-disciplinary, transnational endeavour aimed at ensuring the long-term viability of these unique frogs and their particular habitat.

Bioclimatic and anthropogenic variables shape the occurrence of Batrachochytrium dendrobatidis over a large latitudinal gradient

“…In our study, the species with highest Bd loads were C. gayi (median 436 ZE and a maximum of 409,440 ZE) and R. darwinii (median 1170 ZE and a maximum of 84,709 ZE; Table 1 ), possibly indicating impacts at the population level in these species. We recommend, therefore, that longitudinal population monitoring and Bd surveillance programmes be initiated or continued for these threatened species at Bd -positive sites (e.g., see Binational Conservation Strategy for Darwin's Frog 66 ). We found statistical differences in ZE between aquatic and terrestrial species, which emphasizes the role of aquatic species and aquatic environments in the maintenance and spread of Bd .…”

“…We found statistical differences in ZE between aquatic and terrestrial species, which emphasizes the role of aquatic species and aquatic environments in the maintenance and spread of Bd . Population declines due to Bd infection can occur in the absence of evident mass mortality or other obvious signs of disease, as evidenced by the Bd -driven declines of R. darwinii in Chile 53 and the possible extinction of its sister species, R. rufum , which has not been observed since 1981 48 , 52 , 66 .…”

Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen

“…The study incorporated two nearby plots per population. These populations are within native old‐growth forests of similar characteristics, where no other anthropogenic stressors besides Bd are known to occur (Azat et al., 2021). The CR data were collected at two nested levels of capture occasions (i.e.…”

“…All captures were made during the R. darwinii reproductive season (i.e. October–March; Azat et al., 2021). We defined the age class (juvenile or adult) of each captured frog based on its SVL (Valenzuela‐Sánchez et al., 2017).…”

“…Thus, male reproductive effort, in terms of frequency of brooding attempts and number of brooded larvae, can be estimated using field data. Also, this species is highly susceptible to lethal Bd infection (Valenzuela‐Sánchez et al., 2017) and Bd has been proposed as one of the main drivers of its widespread decline and of the possible extinction of its sister species, R. rufum (Azat et al., 2021; Soto‐Azat, Valenzuela‐Sánchez, Clarke, et al., 2013).…”