Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.

Amphibian skin is not to be considered a mere tegument; it has a multitude of functions related to respiration, osmoregulation, and thermoregulation, thus allowing the individuals to survive and thrive in the terrestrial environment. Moreover, amphibian skin secretions are enriched with several peptides, which defend the skin from environmental and pathogenic insults and exert many other biological effects. In this work, the beneficial effects of amphibian skin peptides are reviewed, in particular their role in speeding up wound healing and in protection from oxidative stress and UV irradiation. A better understanding of why some species seem to resist several environmental insults can help to limit the ongoing amphibian decline through the development of appropriate strategies, particularly against pathologies such as viral and fungal infections.

Measuring population changes and trends is essential to identify threatened species, and is requested by several environmental regulations (e.g. European Habitat Directive). However, obtaining this information for small and cryptic animals is challenging, and requires complex, broad-scale monitoring schemes. How should we allocate the limited resources available for monitoring, to maximize the probability of detecting declines? The analysis of simulated data can help to identify the performance of monitoring scenarios across species with different features. We simulated data of populations with a wide range of abundance, detection probability and rate of decline, and tested under which circumstances open-population N-mixture models can successfully detect the decline of populations. We tested multiple monitoring strategies, to identify the ones having the highest probability of detecting declines. If 30 sites are surveyed, strong declines (≥30%) can be successfully spotted for nearly all the simulated species, except the species with lowest abundance and detection probability. Weaker declines are successfully identified only in species that are easy to detect and have high abundance. Increasing the number of sites quickly increases model power, but hundreds of sites would require monitoring to measure trends of the least detectable species. For most of species, performance of monitoring was improved by: surveying many sites with a few replicates per site; surveying many small sites instead of a few large sites; combining data from sites monitored for multiple species. Our findings show that one single monitoring approach cannot be appropriate for all the species, and that surveying efforts should be modulated across them, according to their detection probabilities and abundances. We provide quantitative values on how the number of surveys and the number of sites to be surveyed can be assigned to different species, and emphasize the need of planning to maximize the performance of monitoring.

Specialization is typically inferred at population and species level but in the last decade many authors highlighted this trait at the individual level, finding that generalist populations can be composed by both generalist and specialist individual. Despite hundreds of reported cases of individual specialization there is a complete lack of information on inter-individual diet variation in specialist species. We studied the diet of the Italian endemic Spectacled Salamander (Salamandrina perspicillata), in a temperate forest ecosystem, to disclose the realised trophic niche, prey selection strategy in function of phenotypic variation and inter-individual diet variation. Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones. Analyses of inter-individual diet variation showed that a subset of animals exhibited a broader trophic niche, adopting different foraging strategies. Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent. At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.