Wouter Beukema

• PhD
• Project manager & researcher at Ravon

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 pathogenicit...

The existence of two or more distinctly coloured phenotypes among individuals of an interbreeding population is known as colour polymorphism. In amphibians, this phenomenon is pervasive among anurans, but rare or absent among salamanders and caecilians, respectively. Here, we examine whether various distinct phenotypes of Salamandra salamandra in N...

Recognizing the influence of pathogen diversity on infection dynamics is crucial for mitigating emerging infectious diseases. Characterising such diversity is often complex, for instance when multiple pathogen variants exist that interact differently with the environment and host. Here, we explore genotypic and phenotypic variation of Batrachochytr...

First report of Ophidiomyces ophidiicola in wild barred grass snakes (Natrix helvetica) in the Netherlands Ophidiomyces ophidiicola is the causative agent of ophidiomycosis (also called snake fungal disease) and has been associated with mycosis in individual snakes and population declines in several North American snake species. While cases of ophi...

Mosquitoes are important vectors of disease pathogens and multiple species are undergoing geographical shifts due to global changes. As such, there is a growing need for accurate distribution predictions. Ecological niche modelling (ENM) is an effective tool to assess mosquito distribution patterns and link these to underlying environmental prefere...

Background Predicting and explaining species occurrence using environmental characteristics is essential for nature conservation and management. Species distribution models consider species occurrence as the dependent variable and environmental conditions as the independent variables. Suitable conditions are estimated based on a sample of species o...

Ophidiomyces ophidiicola is the causative agent of ophidiomycosis (also called snake fungal disease) and has been associated with mycosis in individual snakes and population declines in several North American snake species. While cases of ophidiomycosis from North America have been numerous in the past two decades, reports from Europe remain sparse...

Understanding wildlife responses to novel threats is vital in counteracting biodiversity loss. The emerging pathogen Batrachochytrium salamandrivorans (Bsal) causes dramatic declines in European salamander populations, and is considered an imminent threat to global amphibian biodiversity. However, real-life disease outcomes remain largely uncharact...

When two putatively cryptic species meet in nature, hybrid zone analysis can be used to estimate the extent of gene flow between them. Two recently recognized cryptic species of banded newt (genus Ommatotriton) are suspected to meet in parapatry in Anatolia, but a formal hybrid zone analysis has never been conducted. We sample populations throughou...

When two putative cryptic species meet in nature, hybrid zone analysis can be used to estimate the extent of gene flow between them. Two recently recognized cryptic species of banded newt (genus Ommatotriton) are suspected to meet in parapatry in Anatolia but a formal hybrid zone analysis has never been conducted. We sample populations throughout t...

Starting in 2010, rapid fire salamander (Salamandra salamandra) population declines in northwestern Europe heralded the emergence of Batrachochytrium salamandrivorans (Bsal), a salamander‐pathogenic chytrid fungus. Bsal poses an imminent threat to global salamander diversity owing to its wide host range, high pathogenicity, and long‐term persistenc...

While epizootics increasingly affect wildlife, it remains poorly understood how the environment shapes most host-pathogen systems. Here, we employ a three-step framework to study microclimate influence on ectotherm host thermal behaviour, focusing on amphibian chytridiomycosis in fire salamanders (Salamandra salamandra) infected with the fungal pat...

Biodiversity loss affects ecosystem functioning. Top down effects of amphibian declines on the trophic food web of the forest floor are poorly understood. Here we quantify and explain the effects of disease-driven loss of salamanders on the dynamics of forest leaf litter. Using paired mesocosms, within a Belgian forest, we tested the effect of fire...

The Chinese-Myanmar border area forms part of a long-acknowledged biodiversity hotspot. This region is characterised by dramatic topography and diverse landscapes, which support a high degree of biodiversity and endemism that remains largely understudied. Based on recent survey efforts we here describe a new frog species of the genus Odorrana from...

IUCN Assessment

Wildlife diseases are contributing to the current Earth's sixth mass extinction; one disease, chytridiomycosis, has caused mass amphibian die-offs. While global spread of a hypervirulent lineage of the fungus Batrachochytrium dendrobatidis (BdGPL) causes unprecedented loss of vertebrate diversity by decimating amphibian populations, its impact on a...

While epizootics increasingly affect wildlife, it remains poorly understood how the environment shapes most host-pathogen systems. Here, we employ a three-step framework to study microclimate influence on ectotherm host thermal behaviour, focusing on amphibian chytridiomycosis in fire salamanders (Salamandra salamandra) infected with the fungal pat...

Quantifying intraspecific variation in heat tolerance is critical to understand how species respond to climate change. In a previous study, we recorded variability in critical thermal maxima (CTmax) by 3 °C among populations of small Iberian lizard species, which could substantially influence predictions of climate-driven activity restriction. Here...

The last species list of the European herpetofauna was published by Speybroeck, Beukema and Crochet (2010). In the meantime, ongoing research led to numerous taxonomic changes, including the discovery of new species-level lineages as well as reclassifications at genus level, requiring significant changes to this list. As of 2019, a new Taxonomic Co...

Lambert et al . question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm th...

The Corsican Painted Frog Discoglossus montalentii has received little research attention since its discovery, which creates uncertainty about its distribution and conservation status. We here use a combination of field surveys, ecological niche modelling (ENM) and niche overlap analyses to (i) update the D. montalentii distribution; (ii) determine...

The widespread observation that heat tolerance is less variable than cold tolerance (‘cold‐tolerance asymmetry’) leads to the prediction that species exposed to temperatures near their thermal maxima should have reduced evolutionary potential for adapting to climate warming. However, the prediction is largely supported by species‐level global studi...

The demise of amphibians? Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus Batrachochytrium dendrobatidis was identified in amphibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele et al. found that the fungus has caused declines in amphibian populations every...

Aim Identifying 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,...

Research addressing the effects of global warming on the distribution and persistence of species generally assumes that population variation in thermal tolerance is spatially constant or overridden by interspecific variation. Typically, this rationale is implicit in sourcing one critical thermal maximum (CTmax) population estimate per species to mo...

Presentamos nuevos registros de distribución en malla UTM de 10x10 km para Psammodromus algirus, Coronella austriaca y Vipera latastei en Soria, Castilla y León (España). Así mismo reportamos la sintopía de Podarcis muralis y Podarcis liolepis en dicha área. Adicionalmente, proveemos información detallada de la ocurrencia de 17 especies de reptiles...

ANB startte in februari 2015 een onderzoeksproject op aan de Universiteit Gent voor een actieve bewaking en een risicoanalyse van de ziekte chytridiomycose in Vlaanderen. Deze ziekte is beperkt tot amfibieën, en wordt veroorzaakt door de schimmels Batrachochytrium dendrobatidis (treft kikkers, padden en salamanders) of B. salamandrivorans (treft en...

Update of standard list of Dutch common names of the European amphibians and reptiles Advances in taxonomic insights of the European amphibians and reptiles have necessitated a revision of the standard list of Dutch names published in 2005. The new list includes the species in the Field guide to the amphibians and reptiles of Britain and Europe by...

The unusually yellow-patched populations of Salamandra atra isolated on the Altopiano dei Sette Comuni (S. atra aurorae) and on the Pasubio massif (S. atra pasubiensis) are recognized to have great scientific and conservation value. Despite the absence of extended surveys and long-term monitoring, irregular visits and short-term researches during t...

Beukema et al. Introduce the genus salamandra comprising the well-known fire salamanders.

Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent th...

Field sites in Europe at which Batrachochytrium salamandrivorans fungus was and was not detected in amphibians, 2010–2016.

In vertebrates, the relative proportion of the number of trunk and caudal vertebrae is an important determinant of body shape. While among amphibians frogs and toads show low variation in vertebrae numbers, in salamanders the numbers of trunk and caudal vertebrae vary widely, giving rise to phenotypes in the range from short-bodied and long-tailed...

A new, yet old, threat to amphibians Globally, populations of amphibians have been severely affected by a disease caused by the fungus Batrachochytrium dendrobatidis . Recently, some European salamander populations were decimated by the emergence of a new, related chytrid fungus, B. salamandrivorans . Martel et al. screened amphibians across contin...

Die Arbeit faßt 1580 Funddaten von reptilien und Amphibien auf der insel Samos (Griechenland) aus den letzten Jahren (1993-2012) zusammen. Alle Funde wurden auf einem 1 km x 1 km raster verortet, wobei 40 % der Zellen (261 von insgesamt 648) zumindest eine Beobachtung einer Art aufwiesen. Auf dieser Datengrundlage wurden Verbreitungsmuster und ökol...

As part of his function as assistant to the director of the Rijksmuseum van Natuurlijke Historie in Leiden, the Netherlands (RMNH, currently Naturalis Biodiversity Center), the German biologist Hermann Schlegel received several herpetological specimens from Algeria for identification purposes during the mid-19th century. These specimens were sent t...

NATURAL HISTORY NOTES 329 outdoor lights in residential areas, especially if the residential area is located near a wetland or prior to rains (JJM and GN, pers. obs.), and under such conditions predation on dragonflies by geckos is possible, as reported herein. The observations described herein therefore not only again raise the question of size an...

Until now, Asian amphibians appear to have largely escaped declines driven by chytridiomycosis. Vietnamese salamanders that belong to the genus Tylototriton are rare and have a patchy distribution in mountainous areas, falling within the proposed environmental envelope of chytrid infections, surrounded by Batrachochytrium dendrobatidis infected reg...

The distribution, ecology and conservation status of the Syrian urodeles Salamandra infraimmaculata and Ommatotriton vittatus are poorly known. We present the results of a field study, conducted in February 2009. Salamandra infraimmaculata was found at six localities, ranging from 228 to 960 m a.s.l., and co-occurred with O. vittatus at three local...

The amphibian fauna of the Kingdom of Morocco was traditionally regarded as poor and closely related to its European counterpart. However, an increase in research during the last decades revealed a considerable degree of endemism amongst Moroccan amphibians, as well as phenotypic and genotypic inter- and intraspecific divergence. Despite this incre...

North America and the neotropics harbor nearly all species of plethodontid salamanders. In contrast, this family of caudate amphibians is represented in Europe and Asia by two genera, Speleomantes and Karsenia, which are confined to small geographic ranges. Compared to neotropical and North American plethodontids, mortality attributed to chytridiom...

Overview of the sampled Speleomantes species, sampling localities, sample size and sampling dates. Seconds have been removed from coordinates to prevent illegal collection. (DOCX)

Overview of the sampled Speleomantes species for collection of skin secretions and respective sampling localities. Seconds have been removed from coordinates to prevent illegal collection (DOCX)

The Moroccan spadefoot toad (Pelobates varaldii) has received little scientific attention since its discovery. Currently, P. varaldii is listed as Endangered on the IUCN Red List due to a multitude of threats, while its distribution is partially unknown and fragmented. The current study addresses distribution, threats and the potential niche using...

Genetic divergence of mitochondrial DNA does not necessarily correspond to reproductive isolation. However, if mitochondrial DNA lineages occupy separate segments of environmental space, this supports the notion of their evolutionary independence. We explore niche differentiation among three candidate species of crested newt (characterized by disti...

Occurrence data for crested newt (candidate) species. (XLS)

ENFA results for each pairwise comparison of (candidate) species. (PDF)

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 rec...

The integration of spatial area prioritization algorithms and species distribution modelling has shown great promise in conservation planning in recent years. However, despite the fact that reptiles and amphibians have the highest threat status of all terrestrial vertebrates, these species are often under-represented in conservation planning. The K...

Ontogenetic, post-metamorphic pattern development is a rarely studied topic in amphibian science. As there are indications that the pattern of Salamandra corsica might expand over time, digital image analyses were applied in order to measure several phenol typical variables which were related to the snout vent length. Results show a significant inc...

While the knowledge of the Philippine reptiles and amphibians is steadily increasing, there is still a lack of knowl-edge on the herpetofauna of Mindanao, the second largest island of the country. The herpetofaunal composition of the Mt. Kitanglad Range in north-central Mindanao is only partially known, whereas the relatively extensive but fragment...

The opening of the Gibraltar land bridge occurred at the end of the Messinian Salinity Crisis approximately 5.3 Mya, and was one of the main causes of vicariance between European and north-west African amphibians, resulting in the origin of several new species. However, little is currently known about the causes for post-Messinian amphibian differe...

Research on the taxonomy of European amphibians and reptiles has increased noticeably over the last few decades, indicating the need for recognition of new species and the cancellation of others. This paper provides a critical review of recent changes and draws up a tentative species list.

Research on the taxonomy of European amphibians and reptiles has increased noticeably over the last few decades, indicating the need for recognition of new species and the cancellation of others. This paper provides a critical review of recent changes and draws up a tentative species list.

During an excursion to the southern Lycian coast (southwestern Turkey) from the 12 th February to the 21 st of February 2007 observations were made on three populations of Lyciasalamandra luschani finikensis, while a fourth population was discovered on the Çatal Tepesi between 190 and 200 m a. s. l. Notes on the vegetation communities of the habita...

Aurora's Alpine Salamander is a limited distributed subspecies endemic to the Altopiano di Asiago, Veneto. In the current paper the occurrence of Salamandra atra aurorae is described for the Altopiano di Vezzena, Trentino. The aim of this paper is to review the distribution as well as to comment on the conservational status of the subspecies in Tre...

During May 2004 and May 2006 visits were made to the Fire Salamanders of the Ten-di and Infierno valleys (S. s. alfredschmidti). For the first time larvae of this subspecies were found central in the Tendi river valley. The prescence of this subspecies in the Infierno valley was not yet known. The salamanders there are characterised by a high morph...