Batrachochytrium dendrobatidis in Germany: distribution, prevalences, and prediction of high risk areas

Abstract

In Germany, the pathogenic fungus Batrachochytrium dendrobatidis (Bd) was detected in 11 indigenous frog species, 4 newt species, and 1 salamander species in 64 out of the 181 locations (35%) investigated. Among the 3450 samples collected between 2003 and 2011, 284 (8.2%) were positive for Bd infections. The highest prevalences were observed in Alytes obstetricans (17.8% of individuals, 20% of populations), followed by Ichthyosaura alpestris (14.7%, 22.2%), Bombina variegata (13.9%, 38.5%), and water frogs comprising 2 species, Pelophylax lessonae and P. ridibundus, and their hybrid form P. esculentus (13.5%, 29.0%). Bd is widespread; areas of higher prevalence were detected in eastern, southeastern, western, and southwestern Germany. Our data indicate that drift fencing of amphibians is not a risk factor for the anthropogenic spread of Bd. Although chytridiomycosis outbreaks have never been observed in Germany, it cannot be excluded that Bd infections affect the dynamics of local amphibian populations. Among the questions still to be answered is whether juveniles are more susceptible to Bd infections than adults. Further work, especially long-term observations including capture-mark-recapture studies, is required to clarify the impact Bd has on amphibians in Germany and Central Europe. KEY WORDS: Batrachochytrium dendrobatidis · Chytridiomycosis · Germany · Distribution · Prevalence · Amphibian fencing Resale or republication not permitted without written consent of the publisherDis Aquat Org 107: [49][50][51][52][53][54][55][56][57][58][59] 2013 2005, Schmidt et al. 2009), Italy (Federici et al. 2008, and on Sardinia (Bovero et al. 2008, Bielby et al. 2009). Epidemiological data from the northern and eastern parts of Europe, however, are scarce.In Germany, the first field record of Bd was obtained from the water frog hybrid Pelophylax esculentus, which was sampled in the state of Brandenburg, northeastern Germany (Mutschmann et al. 2000). Further records originated from P. esculentus, found in 2003 near Neuwied (Rhineland-Palatinate), Triturus alpestris (2001 and 2003) collected in southern Germany (Swabian Alb), and Salamandra salamandra (2001 and 2002) kept in an outdoor terrarium (Mutschmann 2007). Preliminary prevalence data ob tained from all indigenous German amphibian species except S. atra indicate that Bd is widespread in Germany and is able to infect all species (Ohst et al. 2011). Chytridiomycosis outbreaks, however, have never been observed; therefore the role Bd plays in population declines in Germany, as in the whole of Central Europe, is not yet clear. We therefore as a first step estimated species-, population-, and locality-specific prevalence rates of Bd infections in Germany. Based on 3450 tissue samples from 181 localities, we aimed to explore the spatial patterns of Bd infections and detect areas of increased Bd prevalences in Germany as a basis for risk assessment and conservation management.Despite the role Bd plays in the dynamics of am phibian populations, destruction,...

Fragile coexistence of a global chytrid pathogen with amphibian populations is mediated by environment and demography

“…While prevalence varies between 4.5% and 32%, infection intensities are generally low [11,14,16,[20][21][22][23][24]. Nonetheless, lethal chytridiomycosis has been observed in the Apennine (continental Italy) subspecies of yellow-bellied toad, B. variegata pachypus [25].…”

Batrachochytrium dendrobatidis is present in Poland and associated with reduced fitness in wild populations of Pelophylax lessonae

“…To date, in the literature only Sura et al (2012), referring to personal communication with T. Ohst, have reported that a German−Swiss research team detected Bd in 29 of 161 sampled water frogs from 5 localities, but georeferenced data are unavailable. Therefore, Bd in Poland should be treated as insufficiently investigated, although the fungus has commonly been observed in neighboring countries (Ohst et al 2013, Baláž et al 2014a. The aim of our study was a survey of the Bd presence in Poland, as it is a potential factor in fluctuations or decreases in local amphibian populations.…”

No evidence for effects of infection with the amphibian chytrid fungus on populations of yellow-bellied toads

“…Therefore, it is listed as highly endangered for Germany and also for the federal state of Hesse (Kühnel et al 2009, Alfermann et al 2010. Although chytridiomycosis has not been suggested to play a main role in yellow-bellied toad declines (Kuzmin et al 2009) and outbreaks of chytridiomycosis have not yet been observed in any amphibian species in Germany, impacts on populations cannot be ruled out (Ohst et al 2013) without long-term monitoring of infected populations.…”

“…In a European-wide study on Bd infections, members of the families Alytidae and Bombinatoridae were significantly more likely to be infected than other European amphibian groups, and the highest infection rates were found in juvenile yellow-bellied toads Bombina variegata from Hungary (Baláž et al 2014). Hence, B. variegata is at least a tolerant species, and the question is if the species or populations/individuals are also susceptible to chytridiomycosis (see Van Rooij et al 2015) In Germany, Bd-infected individuals have been found in populations of almost all autochthonous amphibian species (Lötters et al 2012, Ohst et al 2013. In the first nationwide Bd screening by Ohst et al (2013), 15 out of 108 tested yellow-bellied toads and 5 out of 13 tested populations were infected with Bd.…”

“…Hence, B. variegata is at least a tolerant species, and the question is if the species or populations/individuals are also susceptible to chytridiomycosis (see Van Rooij et al 2015) In Germany, Bd-infected individuals have been found in populations of almost all autochthonous amphibian species (Lötters et al 2012, Ohst et al 2013. In the first nationwide Bd screening by Ohst et al (2013), 15 out of 108 tested yellow-bellied toads and 5 out of 13 tested populations were infected with Bd. For the German federal state of Hesse, Rasmussen et al (2013) conducted a regional Bd screening.…”