Authors: Erens, Jesse; Preißler, Kathleen;Speybroeck, Jeroen;Beukema, Wouter;Spitzen-van der Sluijs, Annemarieke;Stark, Tariq;Schmidt, Benedikt R.;Martel, An;Steinfartz, Sebastian;Pasmans, Frank;

The mass extinction of amphibians presents a major part of global biodiversity loss, and anthropogenic pathogen spread is an increasingly documented threat to the survival of amphibian populations. While the fungal pathogen Batrachochytrium dendrobatidis has been implicated in worldwide declines of frog species and populations, its sister species, Batrachochytrium salamandrivorans (Bsal), has been signalled as an emerging conservation threat to global salamander diversity. We performed a multidisciplinary and international assessment to the continued effects of Bsal invasion on wild fire salamander (Salamandra salamandra) populations, a highly susceptible European species. For this purpose, we combined monitoring data from citizen-science programs with novel survey efforts to evaluate: 1) ongoing population dynamics and disease prevalence; 2) extant demographic structure and recruitment; 3) spatial population patterns and habitat associations; and 4) host resistance and population genetic effects. Our results highlight variable population-level impacts, indicating low-level population persistence but also an apparent extinction event. Additionally, we found enduring signs of age-structure truncation, disparate population clustering and habitat associations, while we found no indications of increased host resistance but also no signs of marked genetic deterioration. Our results provide new post-outbreak conservation prospects and avenues for ongoing research in the midterm after Bsal invasion in Europe.