Pinniped comparative survival data

Survival rates are a central component of life-history strategies of large
vertebrate species.  However, comparative studies seldom
investigate interspecific variation in survival rates with respect to
other life-history traits, especially for males.  The lack of
such studies could be due to the challenges associated with obtaining
reliable datasets, incorporating information on the 0-1 probability scale,
or dealing with several types of measurement error in life-history traits,
which can be a computationally intensive process that is often absent in
comparative studies.  We present a quantitative approach using
Bayesian phylogenetically controlled regression with the flexibility to
incorporate uncertainty in estimated survival rates and quantitative
life-history traits while considering genetic similarity among species and
uncertainty in relatedness.  As with any comparative analysis,
our approach makes several assumptions regarding the generalizability and
comparability of empirical data from separate studies.  Our model
is versatile in that it can be applied to any species group of interest
and include any life-history traits as covariates.  We used an
unbiased simulation framework to provide “proof of concept” for our model
and applied a slightly richer model to a real-data example for
pinnipeds.  Pinnipeds are an excellent taxonomic group for
comparative analysis, but survival rate data are scarce.  Our
work elucidates the challenges associated with addressing important
questions related to broader ecological life-history patterns and how
survival-reproduction tradeoffs might shape evolutionary histories of
extant taxa.  Specifically, we underscore the importance of
having high-quality estimates of age-specific survival rates and
information on other life-history traits that reasonably characterize a
species for accurately comparing across species.