Batrachochytrium Salamandrivorans Research Articles

The importance of biological plausibility for data poor models in the face of an immediate threat by an emerging infectious disease: a reply to Katz and Zellmer (2018)

Species distribution models (SDM) are an important tool to predict the invasion risk of alien species and emerging infectious diseases. However, building reliable models in early stages of invasions is a challenging task. Katz and Zellmer (Biol Invasions 20:2107–2119, 2018) addressed this problem and presented a framework for model selection for data-poor newly invasive species. Based on data of the recently discovered and invasive amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal), they built SDM and gave concluding implications for model selection in general and for Bsal in its invasive range in particular. In our opinion the authors’ SDM and their final processing show severe flaws and lead to a biologically implausible (although statistically best) model, which they used to promote their framework. We here intend to remind readers of the importance of biological relevance and plausibility of SDM, especially its input data, by highlighting some deficiencies and their implications for the biological relevance of the predictions. We further emphasize considerations and recommendations to improve the biological relevance and to make model evaluation more comprehensible. Though biological relevance is a basic SDM rationale, it is of particular importance when limited data impede a ‘proper’ model evaluation. If a prediction is evaluated as good or best by some statistical measure, but is obviously implausible in a biological sense, we should not ignore the biology of our model species. Especially in the face of an imminent threat such as the spreading Bsal, when immediate conservation or management actions are needed, wrong implications based on biologically implausible models may have severe counterproductive consequences.

Identifying Common Decision Problem Elements for the Management of Emerging Fungal Diseases of Wildlife

Emerging infectious diseases (EIDs) of wildlife have characteristics that make them difficult to manage, leading to reactive and often ineffective management strategies. Currently, two fungal pathogens, Pseudogymnoascus destructans (Pd) and Batrachochytrium salamandrivorans (Bsal), are causing declines in novel host species. To improve the application of management strategies addressing the risk of these pathogens to North American wildlife, we queried wildlife managers about their concerns regarding managing populations of bats and amphibians potentially impacted by Pd and Bsal. Using these responses, we identified aspects of each decision problem that were shared across pathogens, regions and agencies – and found similarities in decision-problem elements for disease management. Reframing management problems as decisions can enable managers to identify similarities across EIDs, i.e. uncertainties within management actions, and improve reactive responses if proactive management is not possible. Such an approach recognizes context-specific constraints and identifies relevant uncertainties that must be reduced in developing a response.

Isolation and Identification of Alkaloids from Poisons of Fire Salamanders ( Salamandra salamandra).

Fire salamanders ( Salamandra salamandra) are conspicuously colored amphibians secreting a skin poison that contains unique steroid alkaloids such as samandarine (1) and samadarone (2), exhibiting toxic as well as antimicrobial activities. Because of their antipredatory and anti-infectious functions, alkaloids from Salamandra poison are of interest with regard to the threat that the lethal fungus Batrachochytrium salamandrivorans ( Bsal) poses to salamanders. Nevertheless, reliable data on the biological activity of Salamandra alkaloids are scarce, in part due to the difficulty to obtain and study those substances. Thus, isolation of pure salamander alkaloids is an important task that might directly contribute to the understanding of Bsal infections. Here we present a noninvasive isolation procedure for samandarine (1) and O-acetylsamandarine (3), as well as for two new alkaloids, O-3-hydroxybutanoylsamandarine (4) and samanone (6), using HPLC. For the first time, high-field NMR data are presented for these alkaloids. Analysis using GC/MS and ESI+-MS, provided important information on the structural variability of these salamander alkaloids.

Quantifying the burden of managing wildlife diseases in multiple host species.

Mitigation of infectious wildlife diseases is especially challenging where pathogens affect communities of multiple host species. Although most ecological studies recognize the challenge posed by multiple-species pathogens, the implications for management are typically assessed only qualitatively. Translating the intuitive understanding that multiple host species are important into practice requires a quantitative assessment of whether and how secondary host species should also be targeted by management and the effort this will require. Using a multiple-species compartmental model, we determined analytically whether and how intensively secondary host species should be managed to prevent outbreaks in focal hosts based on the reproduction number of individual host species and between-species transmission rates. We applied the model to the invasive pathogenic fungus Batrachochytrium salamandrivorans in a 2-host system in northern Europe. Avoiding a disease outbreak in the focal host (fire salamanders [Salamandra salamandra]) was impossible unless management also heavily targeted the secondary host (alpine newts [Ichthyosaura alpestris]). Preventing an outbreak in the community required targeted removal of at least 80% of each species. This proportion increased to 90% in the presence of an environmental reservoir of B. salamandrivorans and when the proportion of individuals removed could not be adjusted for different host species (e.g., when using traps that are not species specific). We recommend the focus of disease-mitigation plans should shift from focal species to the community level and calculate explicitly the management efforts required on secondary host species to move beyond the simple intuitive understanding that multiple host species may all influence the system. Failure to do so may lead to underestimating the magnitude of the effort required and ultimately to suboptimal or futile management attempts.

A first screening of chytrid fungus Batrachochytrium in amphibians in French zoos

Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) screening was carried out in captive amphibians in order to establish the presence of these fungal pathogens in French zoos. Over a period of 3 years, 437 skin swabs were collected at eight French zoos and one private breeding centre [38 species of Anura, 7 species and 2 subspecies of Urodela (salamanders and newts), and 1 caecilian species] and these were analysed using qPCR. None of the samples revealed the presence of Bsal. Bd was detected four times on three species – American bullfrog Lithobates catesbeianus, Common midwife toad Alytes obstetricans and Yellow‐bellied toad Bombina variegata – all of which originated from or were in contact with the natural environment.

Apparent absence of Batrachochytrium salamandrivorans in wild urodeles in the United Kingdom

Whether an infectious disease threat to wildlife arises from pathogen introduction or the increased incidence of an already-present agent informs mitigation policy and actions. The prior absence of a pathogen can be difficult to establish, particularly in free-living wildlife. Subsequent to the epidemic emergence of the fungus, Batrachochytrium salamandrivorans (Bsal), in mainland Europe in 2010 and prior to its detection in captive amphibians in the United Kingdom (UK), we tested archived skin swabs using a Bsal-specific qPCR. These samples had been collected in 2011 from 2409 wild newts from ponds across the UK. All swabs were negative for Bsal. Bayesian hierarchical modelling suggests that Bsal was absent from, or present at very low levels in, these ponds at the time of sampling. Additionally, surveillance of newt mortality incidents, 2013–2017, failed to detect Bsal. As this pathogen has been shown to be widespread in British captive amphibian collections, there is an urgent need to raise awareness of the importance of effective biosecurity measures, especially amongst people with captive amphibians, to help minimise the risk of Bsal spreading to the wild. Continued and heightened wild amphibian disease surveillance is a priority to provide an early warning system for potential incursion events.

Potential risk of Batrachochytrium salamandrivorans in Mexico.

The recent decline in populations of European salamanders caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) has generated worldwide concern, as it is a major threat to amphibians. Evaluation of the areas most suitable for the establishment of Bsal combined with analysis of the distribution of salamander species could be used to generate and implement biosecurity measures and protect biodiversity at sites with high salamander diversity. In this study, we identified the areas most suitable for the establishment of Bsal in Mexico. Mexico has the second-highest salamander species diversity in the world; thus, we identified areas moderately to highly suitable for the establishment of Bsal with high salamander diversity as potential hotspots for surveillance. Central and Southern Mexico were identified as high-risk zones, with 13 hotspots where 30% of Mexican salamander species occur, including range-restricted species and endangered species. We propose that these hotspots should be thoroughly monitored for the presence of Bsal to prevent the spread of the pathogen if it is introduced to the country.

Triturus newts

Ben Wielstra introduces Eurasian newts of the genus Triturus.

Growth Regulation in Amphibian Pathogenic Chytrid Fungi by the Quorum Sensing Metabolite Tryptophol.

Amphibians face many threats leading to declines and extinctions, but the chytrid fungal skin pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) have been identified as the causative factors leading to one of the greatest disease-driven losses of amphibian biodiversity worldwide. Infection may lead to different clinical outcomes, and lethal infections are commonly associated with unrestricted, exponential fungal growth in the amphibian epidermis. Mechanisms underpinning Bd and Bsal growth in the amphibian host are poorly understood. Here, we describe a quorum sensing mechanism that allows cell-to-cell communication by Bd and Bsal in order to regulate fungal densities and infection strategies. Addition of chytrid culture supernatant to chytrid cultures resulted in a concentration-dependent growth reduction and using dialysis, small metabolites were shown to be the causative factor. U-HPLC-MS/MS and in vitro growth tests identified the aromatic alcohol tryptophol as a key metabolite in regulating fungal growth. We determined tryptophol kinetics in both Bd and Bsal and confirmed the autostimulatory mode of action of this quorum sensing metabolite. Finally, we linked expression of genes that might be involved in tryptophol production, with in vitro and in vivo chytrid growth. Our results show that Bd and Bsal fungi use tryptophol to act as multicellular entities in order to regulate their growth.

Impact of seasonal cycles on host-pathogen dynamics and disease mitigation for Batrachochytrium salamandrivorans

Seasonal cycles have a demonstrated effect on the dynamics of human and animal diseases. However, their quantitative implications for disease mitigation in wildlife are less well studied. We quantitatively investigate the effect of seasonality on chytridiomycosis caused by Batrachochytrium salamandrivorans in European fire salamanders (Salamandra salamandra). Floquet theory is a mathematical tool that allows the analysis of periodic systems. In epidemiology, it can be used to study the fate of a un-/managed host population when confronted with a new pathogen. Based on this theory, we develop a novel metric that captures outbreak dynamics similarly to the non-seasonal basic reproduction number R0, but also accounts for seasonal cycles. We use this Floquet-R0 to determine the management needed to defend a susceptible host population from disease outbreaks. In the B. salamandrivorans case, we found a limited effect of seasonality on disease dynamics and mitigation for two hypothetical European fire salamander populations with different seasonal cycles. However, a general model analysis suggested that Floquet-R0 could deviate up to ±33% from the non-seasonal R0, thus leading to insufficient or unnecessary management if seasonality is ignored. We recommend considering seasonal cycles – especially activity cycles with two peaks – when planning mitigation for chytridiomycosis and other wildlife diseases, because they add a considerable layer of uncertainty to analysis and decision-making. The Floquet-R0 metric we present is an intuitive tool to quantitatively evaluate seasonality of disease and its influence on management.

Detection of elusive fire salamander larvae (Salamandra salamandra) in streams via environmental DNA

Abstract In the face of the global biodiversity crisis, the monitoring of species richness and diversity is experiencing an increased demand entailing a raise in cost and time investment. The analysis of species-specific DNA fragments in environmental samples (eDNA) such as from water or soil, facilitate the molecular detection of species without the specific sampling of individuals. The invasive chytrid fungus Batrachochytrium salamandrivorans (Bsal) is infecting natural fire salamander populations (Salamandra salamandra) and causes chytridiomycosis resulting in infrequent regional extinctions of populations across Central Europe. With regard to the expanding distribution of Bsal over the last years, cost-effective monitoring of fire salamanders is important for the conservation of this species. Based on a real-time quantitative PCR (qPCR) assay, we developed a new protocol to detect S. salamandra larvae in streams via eDNA, using species-specific primers of the mitochondrial control region (D-loop). We tested the efficiency of qPCR primer sets for six combinations of DNA extraction kits coupled with subsequent PCR inhibitor removal kits for obtaining qPCR-detectable S. salamandra eDNA from water filters, that were taken both from natural streams and artificial water tanks in the laboratory as positive controls. We found that the DNeasy Blood & Tissue Kit in combination with the DNeasy PowerClean CleanUp Kit performed best for detecting salamander larvae from natural streams. Our experimental protocol paves the way for resource-saving approaches to monitor S. salamandra larvae, but also confirms the limits to this eDNA approach in that it requires optimized laboratory protocols.

Mitigating Batrachochytrium salamandrivorans in Europe

Abstract The infectious chytrid fungus Batrachochytrium salamandrivorans (Bsal) has been responsible for severe population declines of salamander populations in Europe. Serious population declines and loss of urodelan diversity may occur if appropriate action is not taken to mitigate against the further spread and impact of Bsal. We provide an overview of several potential mitigation methods, and describe their possible advantages and limitations. We conclude that long-term, context-dependent, multi-faceted approaches are needed to successfully mitigate adverse effects of Bsal, and that these approaches should be initiated pre-arrival of the pathogen. The establishment of ex situ assurance colonies, or management units, for species threatened with extinction, should be considered as soon as possible. While ex situ conservation and preventive measures aimed at improving biosecurity by limiting amphibian trade may be implemented quickly, major challenges that lie ahead are in designing in situ disease containment and mitigation post-arrival and in increasing public awareness.

Epidemiological tracing of Batrachochytrium salamandrivorans identifies widespread infection and associated mortalities in private amphibian collections

The amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) infects newts and salamanders (urodele amphibians), in which it can cause fatal disease. This pathogen has caused dramatic fire salamander population declines in Belgium, the Netherlands and Germany since its discovery in 2010. Thought to be native to Asia, it has been hypothesised that Bsal was introduced to Europe with the importation of infected amphibians for the commercial pet trade. Following the discovery of Bsal in captive amphibians in the United Kingdom in 2015, we used contact-tracing to identify epidemiologically-linked private amphibian collections in Western Europe. Of 16 linked collections identified, animals were tested from 11 and urodeles tested positive for Bsal in seven, including the identification of the pathogen in Spain for the first time. Mortality of Bsal-positive individuals was observed in five collections. Our results indicate that Bsal is likely widespread within the private amphibian trade, at least in Europe. These findings are important for informing policy regarding Bsal control strategies.

A salamander’s toxic arsenal: review of skin poison diversity and function in true salamanders, genus Salamandra

Terrestrial salamanders of the genus Salamandra represent one of the most prominent groups of amphibians. They are mainly distributed across Europe but also reach Northern Africa and the Near East. Members of the six currently accepted species have long been known to be poisonous; however, work on their toxins was mostly published in German language, and therefore, many nuances of these studies have remained hidden from the majority of herpetologists and toxinologists. Several Salamandra species are called fire salamanders due to their highly contrasted, black-yellow colouration which probably serves to deter predators, although thorough evidence for aposematism in Salamandra is still lacking. Salamandra skin toxins do not only represent a potent antipredator defence but may also have antimicrobial effects. A better understanding of this dual function of Salamandra skin secretions is of utmost importance in the face of the emergence of a fungal disease causing catastrophic declines of fire salamanders in Central Europe, caused by the fungus Batrachochytrium salamandrivorans. In this review, we summarize the knowledge on Salamandra toxins, providing a list of the compounds so far isolated from their secretion and focusing on the bioactivity of the major compounds in Salamandra secretions, the steroidal alkaloids. We identify priorities for future research, including a screening of co-occurrence of steroidal alkaloids and tetrodotoxins in salamandrids, chemical characterization of already identified novel steroidal compounds, elucidation of the presence and role of peptides and proteins in the secretion, and experimental in vitro and in vivo study of the interactions between bioactive compounds in Salamandra skin secretions and cutaneous fungal and bacterial pathogens.

Asymptomatic infection of the fungal pathogen Batrachochytrium salamandrivorans in captivity

One of the most important factors driving amphibian declines worldwide is the infectious disease, chytridiomycosis. Two fungi have been associated with this disease, Batrachochytrium dendrobatidis and B. salamandrivorans (Bsal). The latter has recently driven Salamandra salamandra populations to extirpation in parts of the Netherlands, and Belgium, and potentially also in Germany. Bsal has been detected in the pet trade, which has been hypothesized to be the pathway by which it reached Europe, and which may continuously contribute to its spread. In the present study, 918 amphibians belonging to 20 captive collections in Germany and Sweden were sampled to explore the extent of Bsal presence in captivity. The fungus was detected by quantitative Polymerase Chain Reaction (qPCR) in ten collections, nine of which lacked clinical symptoms. 23 positives were confirmed by independent processing of duplicate swabs, which were analysed in a separate laboratory, and/or by sequencing ITS and 28 S gene segments. These asymptomatic positives highlight the possibility of Bsal being widespread in captive collections, and is of high conservation concern. This finding may increase the likelihood of the pathogen being introduced from captivity into the wild, and calls for according biosecurity measures. The detection of Bsal-positive alive specimens of the hyper-susceptible fire salamander could indicate the existence of a less aggressive Bsal variant or the importance of environmental conditions for infection progression.

Skin mucosome activity as an indicator of Batrachochytrium salamandrivorans susceptibility in salamanders.

Recently emerged fungal diseases, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are an increasing threat to amphibians worldwide. In Europe, the threat of Bsal to salamander populations is demonstrated by the rapid decline of fire salamander populations in Germany, the Netherlands and Belgium. Although most European urodelans are susceptible to infection in infection trials, recent evidence suggests marked interspecific differences in the course of infection, with potentially far reaching implications for salamander conservation. As a salamander’s skin is the first line of defense against such pathogens, interspecific differences in innate immune function of the skin may explain differential susceptibility. Here we investigate if compounds present on a salamander’s skin can kill Bsal spores and if there is variation among species. We used a non-invasive assay to compare killing ability of salamander mucosomes of four different species (captive and wild Salamandra salamandra and captive Ichtyosaura alpestris, Cynops pyrrhogaster and Lissotriton helveticus) by exposing Bsal zoospores to salamander mucosomes and determining spore survival. In all samples, zoospores were killed when exposed to mucosomes. Moreover, we saw a significant variation in this Bsal killing ability of mucosomes between different salamander host species. Our results indicate that mucosomes of salamanders might provide crucial skin protection against Bsal, and could explain why some species are more susceptible than others. This study represents a step towards better understanding host species variation in innate immune function and disease susceptibility in amphibians.

Skin secretions protect some salamanders from lethal fungal infection

Amphibian populations are crashing worldwide and when the IUCN published the list of 100 most endangered species in 2012, nine amphibians were teetering on the brink of extinction. Threatened by loss of habitat, invasive species and toxins in the environment, amphibians are also at risk from a disease, chytridiomycosis, when infected by either Batrachochytrium dendrobatidis or Batrachochytrium salamandrivorans fungi. However, some species may be able to withstand the lethal fungi. ‘There is growing evidence that antimicrobial substances secreted onto the skin surface prevent chytridiomycosis by limiting the burden of infection’, says Kenzie Pereira from Duquesne University, USA. Yet, little was known about the vulnerability of aquatic salamanders to B. salamandrivorans, so John Pojman, Sr, from Louisiana State University, USA, went fishing for three-toed amphiuma (Amphiuma tridactylum) salamanders with bated minnow traps in a Baton Rouge bayou.Back in the lab, Pereira gently prodded the virtually legless amphibians to collect their skin secretions ready for Damien Wilburn at the University of Washington, USA, to analyse. Wilburn discovered that the major component of the secretions is made up of proteins, which are probably antimicrobial. Meanwhile, Pereira tested the effects of the secretions on the growth of the two fungi in test tubes and she was impressed to see that the secretions completely killed off B. dendrobatidis at concentrations of 75 μg ml−1, while the B. salamandrivorans fungus succumbed completely at 187 μg ml−1.Having confirmed the potency of the salamanders’ skin secretions, Pereira, Pojman and colleagues Brian Crother, David Sever and Clifford Fontenot, Jr, from Southeastern Louisiana University, USA, scrutinised the distribution of the skin glands that produce the antimicrobial and mucous skin secretions. Collecting small sections of skin from museum specimens – ranging from a 72-year-old preserved animal to more-recently collected samples – the team found that there were far more mucous glands than granular glands in the salamander skin, with the highest number of mucous glands occurring around the head. However, the granular glands, which produce the antimicrobial secretions, occurred mainly around the base of the salamander's tail, where they were larger than the granular glands found in other parts of the animal's body. In addition, the researchers found the largest granular glands in a male that had been caught during the mating season, suggesting that the glands may contribute to courtship and communication.Having confirmed that the skin secretions of three-toed amphiuma are capable of killing off lethal B. dendrobatidis and B. salamandrivorans fungi in the lab, Pereira says, ‘The big take-home message from this research is that antimicrobial skin secretions may protect some species of salamander from chytridiomycosis caused by B. salamandrivorans’. In addition, she and PI Sarah Woodley, also from Duquesne University, are keen to test the antifungal powers of the skin secretions of other salamanders to find out how well they may be able to protect themselves from these fungal scourges.

Environmental context and differences between native and invasive observed niches of Batrachochytrium salamandrivorans affect invasion risk assessments in the Western Palaearctic

AbstractAimIdentifying hosts and regions susceptible to invasion by an emerged pathogen is vital to inform early risk assessments. We here show how differences between a pathogen's native and invasive observed niche and their underlying environments affect this process, using the recent emergence of Batrachochytrium salamandrivorans (Bsal) as a critical, empirical example.LocationPalaearctic.MethodsTo quantify observed niches, we first gathered occurrences from the native Asian and invasive European distribution of Bsal. Through ordination in PCA‐bound environmental space, we then applied overlap tests to compare native and invasive Bsal niches with those of 56 putative Western Palaearctic host species. At last, we ensembled bivariate niche models (ESMs) for each Bsal niche to assess how differences in observed niches influenced suitability predictions.ResultsThe observed invasive Bsal niche is a conservative, partially filled subset of its wider native niche. Pathogen–host overlap measured using the narrow invasive niche was nevertheless found to be significantly higher than that of the native niche, which is partly situated in subtropical conditions absent from the Western Palaearctic. ESMs created using the native niche predict high suitability for Bsal throughout Europe. Conversely, a more restricted range was predicted using the invasive niche, which coincides with the presence of oceanic climates in north‐western Europe and several Mediterranean mountain ranges.Main conclusionsUnequal relative availability of environments in native and invasive ranges may lead to underestimation of observed niche overlap between native pathogen populations and putative hosts in the invasive range. The existence of partially filled niches may add uncertainty to overlap measurements, and predictions of potential further spread. Results based on the invasive niche therefore provide a conservative estimate; yet demonstrate, in our case, that Bsal is already present in conditions shared by numerous host species. Further niche filling may accordingly increase risk of salamander diversity across the Western Palaearctic.

Risk of survival, establishment and spread of Batrachochytriumsalamandrivorans (Bsal) in the EU.

Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen of salamanders. Despite limited surveillance, Bsal was detected in kept salamanders populations in Belgium, Germany, Spain, the Netherlands and the United Kingdom, and in wild populations in some regions of Belgium, Germany and the Netherlands. According to niche modelling, at least part of the distribution range of every salamander species in Europe overlaps with the climate conditions predicted to be suitable for Bsal. Passive surveillance is considered the most suitable approach for detection of Bsal emergence in wild populations. Demonstration of Bsal absence is considered feasible only in closed populations of kept susceptible species. In the wild, Bsal can spread by both active (e.g. salamanders, anurans) and passive (e.g. birds, water) carriers; it is most likely maintained/spread in infected areas by contacts of salamanders or by interactions with anurans, whereas human activities most likely cause Bsal entry into new areas and populations. In kept amphibians, Bsal contamination via live silent carriers (wild birds and anurans) is considered extremely unlikely. The risk‐mitigation measures that were considered the most feasible and effective: (i) for ensuring safer international or intra‐EU trade of live salamanders, are: ban or restrictions on salamander imports, hygiene procedures and good practice manuals; (ii) for protecting kept salamanders from Bsal, are: identification and treatment of positive collections; (iii) for on‐site protection of wild salamanders, are: preventing translocation of wild amphibians and release/return to the wild of kept/temporarily housed wild salamanders, and setting up contact points/emergency teams for passive surveillance. Combining several risk‐mitigation measures improve the overall effectiveness. It is recommended to: introduce a harmonised protocol for Bsal detection throughout the EU; improve data acquisition on salamander abundance and distribution; enhance passive surveillance activities; increase public and professionals’ awareness; condition any movement of captive salamanders on Bsal known health status.

Comparison of model selection technique performance in predicting the spread of newly invasive species: a case study with Batrachochytrium salamandrivorans

Species distribution models (SDMs) increasingly have been used to anticipate the spread of invasive species. However, these models are powerful conservation tools only if they are biologically relevant, and thus validation of these models is essential. Here, we evaluate four model selection frameworks for their ability to identify a best fit model of spread under low data conditions early in an invasion, specifically testing the efficacy of methods that utilize absence data in addition to presence data in evaluating models. We test this question using a simulation where we generated data with varying confidence in the accuracy of the absence data, as absences in early invasions may become presences in the future, and increasing quantity of observation data to test the models. We create these simulations based on a real-world example of a newly emergent, invasive fungal pathogen, Batrachochytrium salamandrivorans (Bsal). The simulation demonstrated that AIC and Likelihood consistently outperform both Kappa and AUC in selecting the true model as the best model when data are limited and absence data are low quality, with AIC providing the most conservative results due to penalties for overparameterization. With these results, we then used these techniques to compare five candidate models for predicting the spread of Bsal. Consistent with the simulation, the best fit model of the candidate models for Bsal was inconsistent across the four metrics. However, AIC, which performed best in the simulation study, suggested that the spread of Bsal into Western Europe was best predicted by a combination of bioclimatic suitability, salamander richness, and number of salamander imports. Our results highlight the difficulty in evaluating predictive models when data are limited and of low quality, as with a newly invasive species, but show that these challenges can be partially addressed with the appropriate model selection approach. Use of this approach is critical as SDMs of invasive species are often used to inform conservation policy and efforts before the invasion spreads, when limited data are available.