Broadened occurrence and affected host species of the amphibian pathogen Batrachochytrium dendrobatidis including the Global Panzootic Linage(Bd-GPL) in Norway

Invasive species are considered one of the major factors of extinction and loss of biodiversity worldwide, with freshwater ecosystems being particularly vulnerable.The highly invasive and emerging pathogen Batrachochytrium dendrobatidis (Bd) has led to large-scale declines and extinctions of amphibian populations.Bd was detected in Norway from environmental DNA (eDNA) samples in 2017 in five ponds with smooth (Lissotriton vulgaris) and crested newts (Triturus cristatus).A subsequent eDNA survey of over 100 ponds documented Bd at six more locations, including ponds with common toad (Bufo bufo) and common frog (Rana temporaria).By collecting swab samples from smooth newts, crested newts, common toad and common frog, we investigated the prevalence of Bd on amphibians from 16 locations.Additionally, we collected swabs or bath water from another 28 amphibian ponds.A subset of Bd positive samples were also screened with the Bd global panzootic linage (Bd-GPL) qPCR.We detected Bd from a total of 23 of the 44 screened locations where our results showed low to high prevalence of Bd in smooth newts, crested newts and common toad populations.We also confirm the presence of the Bd-GPL variant in Norway.These results demonstrate that Bd is more widespread in Norway and that a higher percentage of populations are infected with Bd, than previously documented.No mass mortalities of amphibians have been observed in Norway, and it is uncertain if Bd has an impact on Norwegian amphibian populations.