Data from: Rapid emergence of an amphibian pathogen coincided with historic amphibian declines in the Neotropics

The emergence of the fungal pathogen Batrachochytrium dendrobatidis (Bd)
in South America has been attributed to multiple introductions followed by
a bidirectional latitudinal spread along the primary Andean cordilleras.
In Ecuador, this hypothesis is supported by anecdotal reports of
population declines in Bd-susceptible genera such as Telmatobius and
Atelopus during the mid-1980s. To evaluate this pattern, we combined
published Bd records with retrospective screening of museum specimens
collected between 1950 and 2010, along with surveys of contemporary
populations, to characterize the spatial, temporal, and host-specific
dynamics of Bd emergence in Ecuador. We compiled a comprehensive database
of Bd records from Ecuadorian anurans comprising over 7,000 samples and
analyzed patterns of emergence using generalized linear mixed models and
spatial clustering techniques. The dataset was also used to estimate Bd
prevalence across four representative genera: Atelopus, Telmatobius,
Gastrotheca, and Pristimantis. Additionally, Bayesian methods were applied
to assess the probability that Bd was present in Ecuador prior to its
first documented detection. Our results overturn the prevailing narrative
of Bd emergence in the Neotropics and provide a rare, long-term view of an
invasive pathogen’s trajectory from introduction to persistence. We found
that: (1) Bd likely represents a novel pathogen to Ecuador; (2) Bd was
first detected in 1974 and had become widespread by 1980; (3) there is no
evidence supporting a bidirectional wave of spread; and (4) the genera
Atelopus, Telmatobius, and Gastrotheca experienced epizootic disease
dynamics, with declines peaking in the 1990s. We found that Bd is likely a
novel pathogen that was introduced in the early 1970s and peaked in
prevalence during the late 1980s and 1990s. The available evidence
supports the conclusion that an outbreak of chytridiomycosis may lead to
catastrophic declines in Ecuadorian amphibians. Disease dynamics have
since subsided to enzootic coexistence in extant amphibian communities.