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Abstract Ecological niche models (ENMs) have been used frequently to predict the distribution and future spread of the pathogenic chytrid fungusBatrachochytrium dendrobatidis(Bd). Based on the assumption that chytridiomycosis outbreaks are most likely to occur where the conditions are ideal for Bd, many studies have identified high‐risk areas for chytridiomycosis and its associated mortality risk using only known Bd occurrences. However, the presence of a pathogen does not necessarily indicate high infection, disease or associated mortality.We used the BIOMOD2 package implemented in R, 19 bioclimatic variables, and 267 locality records, covering three levels of infection progress (occurrence, high infection loads and disease‐associated mortality), to calculate the potential areas where: (1) Bd is likely to be present, (2) amphibians are prone to harbour high infections and (3) chytridiomycosis‐related mortalities are likely to occur. We evaluate discrepancies among the three potential areas projected by the models, encompassing their spatial extent and associated environmental conditions.When all the Bd occurrences were used, the predicted area subjected to Bd risk covered 17% of the study area. However, when just mortality records were used, the predicted area decreased three‐fold. Notably, the three predicted areas only overlapped in 3% of the total study area, suggesting that the region at risk of mortality plus high infections constituted only one‐fifth of the predicted area for Bd presence. Mean temperature during the wettest and warmest 3 months of the year together with isothermality emerged as the most robust negative predictors in each of the three models.Synthesis and applications. Ecological niche models (ENMs) based on the presence data ofBatrachochytrium dendrobatidis(Bd) can overestimate the mortality risk of chytridiomycosis because the environmental conditions suitable for Bd presence do not always correspond to those conducive to significant host mortality. Distribution modelling can be a powerful tool when used correctly, and this study highlights the significance of careful data selection to ensure alignment with intended objectives. Considering the widespread use of ENMs to inform policy, meticulous design and comprehensive evaluation are imperative. 

Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture–recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex-specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the “unguarded X/Z effect”) or repeat-rich Y/W chromosome (the “toxic Y/W effect”) could accelerate aging in the heterogametic sex in some vertebrate clades. 

Biodiversity loss is one major outcome of human-mediated ecosystem disturbance. One way that humans have triggered wildlife declines is by transporting disease-causing agents to remote areas of the world. Amphibians have been hit particularly hard by disease due in part to a globally distributed pathogenic chytrid fungus ( Batrachochytrium dendrobatidis [ Bd ]). Prior research has revealed important insights into the biology and distribution of Bd ; however, there are still many outstanding questions in this system. Although we know that there are multiple divergent lineages of Bd that differ in pathogenicity, we know little about how these lineages are distributed around the world and where lineages may be coming into contact. Here, we implement a custom genotyping method for a global set of Bd samples. This method is optimized to amplify and sequence degraded DNA from noninvasive skin swab samples. We describe a divergent lineage of Bd , which we call Bd ASIA3, that appears to be widespread in Southeast Asia. This lineage co-occurs with the global panzootic lineage ( Bd GPL) in multiple localities. Additionally, we shed light on the global distribution of Bd GPL and highlight the expanded range of another lineage, Bd CAPE. Finally, we argue that more monitoring needs to take place where Bd lineages are coming into contact and where we know little about Bd lineage diversity. Monitoring need not use expensive or difficult field techniques but can use archived swab samples to further explore the history—and predict the future impacts—of this devastating pathogen. 

Abstract The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.