Data from: Disease and climate effects on individuals drive post-reintroduction population dynamics of an endangered amphibian

The emergence of novel pathogens often has dramatic negative effects on
previously unexposed host populations. Subsequent disease can drive
populations and even species to extinction. After establishment in
populations, pathogens can continue to affect host dynamics, influencing
the success or failure of species recovery efforts. However, quantifying
the effect of pathogens on host populations in the wild is challenging
because individual hosts and their pathogens are difficult to observe.
Here we use long-term mark-recapture data to describe the dynamics of
reintroduced populations of an endangered amphibian (Rana sierrae) and
evaluate the success of these recovery efforts in the presence of a
recently-emerged pathogen, the amphibian chytrid fungus Batrachochytrium
dendrobatidis. We find that high B. dendrobatidis infection intensities
are associated with increases in frog detectability and reductions in
survival. When average infection intensities are high, adults are more
likely to gain infections and less likely to lose infections. We also find
evidence for intensity-dependent survival, with heavily infected
individuals suffering higher mortality. These results highlight the need
in disease ecology for probabilistic approaches that account for
uncertainty in infection intensity using imperfect observational data.
Such approaches can advance the understanding of disease impacts on host
population dynamics, and in the current study will improve the
effectiveness of species conservation actions.