Data: Applying stochastic and Bayesian integral projection modeling to amphibian population viability analysis

Integral projection models (IPMs) can estimate the population dynamics of
species for which both discrete life stages and continuous variables
influence demographic rates. Stochastic IPMs for imperiled species, in
turn, can facilitate population viability analyses (PVAs) to guide
conservation decision-making. Biphasic amphibians are globally
distributed, often highly imperiled, and ecologically well-suited to the
IPM approach. Herein, we present the first stochastic size- and
stage-structured IPM for a biphasic amphibian, the U.S. federally
threatened California tiger salamander (Ambystoma californiense; CTS).
This Bayesian model reveals that CTS population dynamics show the greatest
elasticity to changes in juvenile and metamorph growth and that
populations are likely to experience rapid growth at low density. We
integrated this IPM with climatic drivers of CTS demography to develop a
PVA and examined CTS extinction risk under the primary threats of habitat
loss and climate change. The PVA indicates that long-term viability is
possible with surprisingly high (20–50%) terrestrial mortality, but
simultaneously identified likely minimum terrestrial buffer requirements
of 600–1000 m while accounting for numerous parameter uncertainties
through the Bayesian framework. These analyses underscore the value of
stochastic and Bayesian IPMs for understanding both climate-dependent taxa
and those with cryptic life histories (e.g., biphasic amphibians) in
service of ecological discovery and biodiversity conservation. In addition
to providing guidance for CTS recovery, the contributed IPM and PVA supply
a framework for applying these tools to investigations of
ecologically-similar species.