Landscape connectivity limits the predicted impact of fungal pathogen invasion

Infectious diseases are major drivers of biodiversity loss. The risk of fungal diseases to the survival of threatened animals in nature is determined by a complex interplay between host, pathogen and environment. We here predict the risk of invasion of populations of threatened Mediterranean salamanders of the genus Lyciasalamandra by the pathogenic chytrid fungus Batrachochytrium salamandrivorans by combining field sampling and lab trials. In 494 samples across all seven species of Lyciasalamandra, B. salamandrivorans was found to be absent. Single exposure to a low (1000) number of fungal zoospores resulted in fast buildup of lethal infections in three L. helverseni. Thermal preference of the salamanders was well within the thermal envelope of the pathogen and body temperatures never exceeded the fungus' thermal critical maximum, limiting the salamanders' defense opportunities. The relatively low thermal host preference largely invalidates macroclimatic based habitat suitability predictions and, combined with current pathogen absence and high host densities, suggests a high probability of local salamander population declines upon invasion by B. salamandrivorans. However, the unfavorable landscape that shaped intraspecific host genetic diversity, lack of known alternative hosts and rapid host mortality after infection present barriers to further, natural pathogen dispersal between populations and thus species extinction. The risk of anthropogenic spread stresses the importance of biosecurity in amphibian habitats

Post-epizootic salamander persistence in a disease-free refugium suggests poor dispersal ability of Batrachochytrium salamandrivorans

Lack of disease spill-over between adjacent populations has been associated with habitat fragmentation and the absence of population connectivity. We here present a case which describes the absence of the spill-over of the chytrid fungus Batrachochytrium salamandrivorans (Bsal) between two connected subpopulations of fire salamanders (Salamandra salamandra). Based on neutrally evolving microsatellite loci, both subpopulations were shown to form a single genetic cluster, suggesting a shared origin and/or recent gene flow. Alpine newts (Ichthyosaura alpestris) and fire salamanders were found in the landscape matrix between the two sites, which are also connected by a stream and separated by no obvious physical barriers. Performing a laboratory trial using alpine newts, we confirmed that Bsal is unable to disperse autonomously. Vector-mediated dispersal may have been impeded by a combination of sub-optimal connectivity, limited dispersal ability of infected hosts and a lack of suitable dispersers following the rapid, Bsal-driven collapse of susceptible hosts at the source site. Although the exact cause remains unclear, the aggregate evidence suggests that Bsal may be a poorer disperser than previously hypothesized. The lack of Bsal dispersal between neighbouring salamander populations opens perspectives for disease management and stresses the necessity of implementing biosecurity measures preventing human-mediated spread

New insights on phylogeography and distribution of painted frogs (Discoglossus) in northern Africa and the Iberian Peninsula

Painted frogs (Discoglossus) contain five to six species of Western Palearctic anurans that are mainly distributed in allopatry. We here provide the first comprehensive assessment of the phylogeography of the Moroccan species D. scovazzi and geographically characterize its contact zone with D. pictus in Eastern Morocco. Discoglossus scovazzi shows, in general, a weak phylogeographic structure across Morocco on the basis of mitochondrial DNA sequences of the cytochrome b gene, with only populations centered in the Atlas Mountains characterized by the presence of slightly divergent haplotypes. In eastern Morocco, all populations east of the Moulouya River were clearly assignable to D. pictus. This species was also found along the Mediterranean coast west of the Moulouya, in the cities of Nador and Melilla, suggesting that not the river itself but the wide arid valley extending along much of the river (except close to the estuary) acts as a possible distributional barrier to these frogs. No sympatry of D. scovazzi with D. pictus was observed, and all specimens were concordantly assigned to either species by DNA sequences of cytochrome b and of the nuclear marker RAG1. Species distribution models of the two taxa show largely overlapping areas of suitable habitat, and the two species’ niches are significantly more similar than would be expected given the underlying environmental differences between the regions in which they occur. Comparative data are also presented from the southern Iberian contact zone of D. galganoi galganoi and D. g. jeanneae. These taxa showed less clear-cut distributional borders, extensively shared RAG1 haplotypes, and had instances of sympatric occurrence on the basis of cytochrome b haplotypes, in agreement with the hypothesis of a yet incomplete speciation. In this wide contact zone area we found mitochondrial sequences containing double peaks in electropherograms, suggesting nuclear pseudogenes or (less likely) heteroplasmy, possibly related to the ongoing admixture among the lineagesPeer reviewe

A contribution to the atlas of the terrestrial herpetofauna of Sardinia

Here we report on the combined observations of 10 years of opportunistic field work conducted during short visits to Sardinia, from 1999 to 2012. A total amount of 433 distribution records of 27 species were collected from 187 different localities covering 52 unique UTM squares. We report species presence in 157 new UTM squares and additionally reconfirm previous reported presence in 150 UTM squares. Overall, we produce a remarkable increase in the knowledge of the Sardinian herpetofauna. Notes and observations on ecology, taxonomy and conservation are provided.Peer Reviewe

Do North African Fire Salamanders, Salamandra algira, occur in Tunisia?

Salamandra algira is patchily distributed from north-western Morocco to eastern Algeria. Its occurrence in Tunisia is under debate. In order to examine the presence of S. algira in Tunisia, three field trips were made to suitable habitats in the Medjerda mountains in north-eastern Tunisia. Additionally, phenotypic and morphological examinations of >Tunisian> S. algira museum specimens originating from the ZFMK, Germany, were carried out. No indications for the presence of S. algira in Tunisia were found during the field trips. The ZFMK specimens of Salamandra algira turned out to be most likely middle or eastern European Salamandra salamandra. These results do not support earlier statements on the presence of the species in Tunisia.Peer Reviewe

Samples analyzed for fragments of RAG1, KIAA, SACS and TTN.

<p>Samples analyzed for fragments of RAG1, KIAA, SACS and TTN.</p

The changing views on the evolutionary relationships of extant Salamandridae (Amphibia: Urodela)

<div><p>The phylogenetic relationships among members of the family Salamandridae have been repeatedly investigated over the last 90 years, with changing character and taxon sampling. We review the changing composition and the phylogenetic position of salamandrid genera and species groups and add a new phylogeny based exclusively on sequences of nuclear genes. <i>Salamandrina</i> often changed its position depending on the characters used. It was included several times in a clade together with the primitive newts (<i>Echinotriton</i>, <i>Pleurodeles</i>, <i>Tylototriton</i>) due to their seemingly ancestral morphology. The latter were often inferred as a monophyletic clade. Respective monophyly was almost consistently established in all molecular studies for true salamanders (<i>Chioglossa</i>, <i>Lyciasalamandra</i>, <i>Mertensiella</i>, <i>Salamandra</i>), modern Asian newts (<i>Cynops</i>, <i>Laotriton</i>, <i>Pachytriton</i>, <i>Paramesotriton</i>) and modern New World newts (<i>Notophthalmus</i>, <i>Taricha</i>). Reciprocal non-monophyly has been established through molecular studies for the European mountain newts (<i>Calotriton</i>, <i>Euproctus</i>) and the modern European newts (<i>Ichthyosaura</i>, <i>Lissotriton</i>, <i>Neurergus</i>, <i>Ommatotriton</i>, <i>Triturus</i>) since <i>Calotriton</i> was identified as the sister lineage of <i>Triturus</i>. In pre-molecular studies, their respective monophyly had almost always been assumed, mainly because a complex courtship behaviour shared by their respective members. Our nuclear tree is nearly identical to a mito-genomic tree, with all but one node being highly supported. The major difference concerns the position of <i>Calotriton</i>, which is no longer nested within the modern European newts. This has implications for the evolution of courtship behaviour of European newts. Within modern European newts, <i>Ichthyosaura</i> and <i>Lissotriton</i> changed their position compared to the mito-genomic tree. Previous molecular trees based on seemingly large nuclear data sets, but analysed together with mitochondrial data, did not reveal monophyly of modern European newts since taxon sampling and nuclear gene coverage was too poor to obtain conclusive results. We therefore conclude that mitochondrial and nuclear data should be analysed on their own.</p></div

Presence of tree topologies (referring to [25]) in published Salamandridae phylogenies.

<p>Presence of tree topologies (referring to [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198237#pone.0198237.ref025" target="_blank">25</a>]) in published Salamandridae phylogenies.</p

Best-fitting partitioning schemes of defined subsets with models of nucleotide evolution.

<p>Best-fitting partitioning schemes of defined subsets with models of nucleotide evolution.</p

Bayesian tree of Salamandridae based on four nuclear genes.

<p>Bayesian posterior probabilities/bootstrap support values for the maximum likelihood tree are given at the nodes.</p