Wagner Norman, Neubeck Claus, Guicking Daniela, Finke Lennart, Wittich Martin, Weising Kurt, Geske Christian, Veith Michael
Trier University, Department of Biogeography, Universitätsring 15, 54296 Trier, Germany.
Dis Aquat Organ. 2017 Feb 8;123(1):55-65. doi: 10.3354/dao03090.
The parasitic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause the lethal disease chytridiomycosis in amphibians and therefore may play a role in population declines. The yellow-bellied toad Bombina variegata suffered strong declines throughout western and northwestern parts of its range and is therefore listed as highly endangered for Germany and the federal state of Hesse. Whether chytridiomycosis may play a role in the observed local declines of this strictly protected anuran species has never been tested. We investigated 19 Hessian yellow-bellied toad populations for Bd infection rates, conducted capture-mark-recapture studies in 4 of them over 2 to 3 yr, examined survival histories of recaptured infected individuals, and tested whether multi-locus heterozygosity of individuals as well as expected heterozygosity and different environmental variables of populations affect probabilities of Bd infection. Our results show high prevalence of Bd infection in Hessian yellow-bellied toad populations, but although significant decreases in 2 populations could be observed, no causative link to Bd as the reason for this can be established. Mass mortalities or obvious signs of disease in individuals were not observed. Conversely, we show that growth of Bd-infected populations is possible under favorable habitat conditions and that most infected individuals could be recaptured with improved body indices. Neither genetic diversity nor environmental variables appeared to affect Bd infection probabilities. Hence, genetically diverse amphibian specimens and populations may not automatically be less susceptible for Bd infection.
寄生壶菌蛙壶菌（Batrachochytrium dendrobatidis，简称Bd）可在两栖动物中引发致命疾病壶菌病，因此可能在种群数量下降中发挥作用。黄腹蟾蜍（Bombina variegata）在其分布范围的西部和西北部地区数量大幅减少，因此在德国及黑森州被列为高度濒危物种。壶菌病是否在这种严格保护的无尾目物种的局部数量下降中起作用，此前从未得到验证。我们调查了19个黑森州黄腹蟾蜍种群的Bd感染率，在其中4个种群中进行了为期2至3年的标记重捕研究，检查了重新捕获的受感染个体的生存史，并测试了个体的多位点杂合性以及种群的预期杂合性和不同环境变量是否会影响Bd感染的概率。我们的结果表明，黑森州黄腹蟾蜍种群中Bd感染率很高，但尽管在2个种群中观察到数量显著下降，但无法确定这与Bd之间存在因果关系。未观察到个体出现大规模死亡或明显的疾病迹象。相反，我们表明，在有利的栖息地条件下，受Bd感染的种群有可能增长，并且大多数受感染个体在身体指标改善后能够被重新捕获。遗传多样性和环境变量似乎都不会影响Bd感染概率。因此，遗传多样性高的两栖动物标本和种群不一定对Bd感染的易感性更低。
