Compensatory recruitment is a key demographic mechanism that has allowed the coexistence of populations of susceptible amphibians with Batrachochytrium dendrobatidis (Bd), a fungus causing one of the most devastating emerging infectious disease ever recorded among vertebrates. However, the underlying processes (e.g. density‐dependent increase in survival at early life stages, change in reproductive traits) as well as the level of interpopulation variation in this response are poorly known. We explore potential mechanisms of compensatory recruitment in response to Bd infection by taking advantage of an amphibian system where male reproductive traits are easy to quantify in free‐living populations. The Southern Darwin's frog Rhinoderma darwinii is a vocal sac‐brooding species that exhibits a high susceptibility to lethal Bd infection. Using a 7‐year capture–recapture study at four populations with contrasting Bd infection status (one high prevalence, one low prevalence and two Bd‐free populations), we evaluated whether Bd‐positive populations exhibited a higher adult recruitment and a higher male reproductive effort than Bd‐negative populations. We also estimated population growth rates to explore whether recruitment compensated for the negative impacts of Bd on the survival of adults. In addition, we evaluated a potential demographic signal of compensatory recruitment (i.e. positive relationship between the proportion of juveniles and Bd prevalence) in response to Bd infection using raw count data from 13 R. darwinii populations. The high Bd prevalence population exhibited the highest male reproductive effort and the highest recruitment among the four monitored populations. This led to a growing population during the study period despite high mortality of adult hosts. In contrast, males from the population with low Bd prevalence had a low reproductive effort and this population, which had the lowest adult recruitment, was declining during the study period despite adults having a higher survival in comparison to the high Bd prevalence population. We also found a demographic signal of compensatory recruitment in response to Bd infection in our broader analysis of 13 R. darwinii populations. Our study underlines the importance of interpopulation variation in life‐history strategies on the fate of host populations after infectious disease emergence. Our results also suggest that an increase in reproductive effort can be one of the processes underlying compensatory recruitment in populations of Bd‐susceptible amphibians.

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.

Ranaviruses are the second deadliest pathogens for amphibian populations throughout the world. Despite their wide distribution in America, these viruses have never been reported in Mexico, the country with the fifth highest amphibian diversity in the world. This paper is the first to address an outbreak of ranavirus in captive American bullfrogs (Lithobates catesbeianus) from Sinaloa, Mexico. The farm experienced high mortality in an undetermined number of juveniles and sub-adult bullfrogs. Affected animals displayed clinical signs and gross lesions such as lethargy, edema, skin ulcers, and hemorrhages consistent with ranavirus infection. The main microscopic lesions included mild renal tubular necrosis and moderate congestion in several organs. Immunohistochemical analyses revealed scant infected hepatocytes and renal tubular epithelial cells. Phylogenetic analysis of five partial ranavirus genes showed that the causative agent clustered within the Frog virus 3 clade. Risk assessment with the Pandora+ protocol demonstrated a high risk for the pathogen to affect amphibians from neighboring regions (overall Pandora risk score: 0.619). Given the risk of American bullfrogs escaping and spreading the disease to wild amphibians, efforts should focus on implementing effective containment strategies and surveillance programs for ranavirus at facilities undertaking intensive farming of amphibians.

Amphibian diversity and distribution patterns in Sinaloa state (north-western Mexico) were assessed from the Global Amphibian Assessment database (GAA-2010). A geographic information system (GIS) was used to evaluate diversity based on distribution maps of 41 species, associated with environmental data. The highest α and γ-diversities were identified in the south-eastern portion of the state, in mountain zones with a warm sub-humid climate, whereas the greatest β-diversity (multiplicative formulation) was aggregated in patches in the western portion of the state in mountains with temperate climates. A cluster analysis and Mantel test showed a strong association of Sorensen's dissimilarity (additive formulation of β-diversity) with climate and soil moisture categories rather than physiographic categories. Additionally, the partition of Sorensen´s dissimilarity into its components (turnover and nestedness) showed a gradient of species turnover related to contrasting climate units and a marked pattern of nestedness between the middle mountains and the coastal plain. The results of the study suggest that the highest α and β-diversity values occur in the middle-humidity range as well in the transitional-climate categories. This pattern is unusual for amphibian distributions because the highest global and regional amphibian diversities are typically related to high humidity values and climate stability (warm and wet most of the year). This particular pattern, occurring in a transitional area, encourages further biological and ecological studies to clarify the status of amphibian populations and support conservation measures.

The nurse effect is a positive interaction in which one plant (the nurse) provides conditions that enhance the establishment and growth of another plant species (Callaway 1995). Increased environmental severity appeared to increase the strength of nurse effects (Brooker et al. 2008, Lortie & Callaway 2006). On the one hand, the impact of the nurse effect depends on the magnitude of the environmental changes exerted by the nurse plant. On the other hand, the impact could depend on the number of plant species in the regional pool that respond to such changes. For example, better conditions beneath the crowns of nurse plants might allow the occurrence of species that are sensitive to environmental stress and that occur infrequently in open areas. Thus, if a nurse plant modulates environmental conditions that are critical for the persistence of other plant species, it seems likely that such nurse plants would have greater effects in stressful habitats, where they cause relatively larger environmental mitigation (Badano et al. 2006, Callaway et al. 2002).