Application of Bayesian robust design model to assess the impacts of a hurricane on shorebird demography

Abstract

Abstract. The increasing use of Bayesian inference in population demography requires rapid advancements in modeling frameworks to approach the rigor and flexibility of the current suite of maximum-likelihood models. We developed an unbiased, Jolly-Seber robust design (JSRD) model that is both accessible and generalizable in a Bayesian hierarchical multistate framework. We integrated band and age-classification data to estimate site entry, temporary emigration, and apparent survival rates, as well as estimate ageclass specific abundances. The complete model parameterization is provided in the Appendix S1, as well as tools for simulating capture histories and an assessment of model fit. We applied this model to determine whether these demographic processes in non-breeding population of American oystercatchers (Haematopus palliatus) were affected by a major hurricane event (Hurricane Matthew) in coastal Georgia. The JSRD model was demonstrably unbiased at relatively small sample sizes, and the majority of parameters were identifiable in the fully saturated model parameterization. In the model application, we found that Hurricane Matthew temporarily altered local population abundances of American oystercatchers through increased movements of individuals into and out of the observable population, but mortality rates were largely unaffected. Together, our results suggest that American oystercatchers were largely able to avoid the immediate demographic consequences (i.e., reduced survival) of Hurricane Matthew. Integrating age and band ratios from survey data allowed for more descriptive and potentially less biased estimates of age-specific abundance, relative to estimates generated solely from either mark-resight or survey data.

Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen

“…Subsequently, we used the Bayesian Jolly–Seber Robust Design (JSRD) model (Gibson et al., 2018) to estimate a set of demographic parameters within each of the four populations. At each population, we estimated the average apparent adult survival probability (hereafter, ‘survival probability’) to corroborate previous findings of a reduced survival probability in Bd‐positive R. darwinii populations (Valenzuela‐Sánchez et al., 2017).…”

“…Briefly, the JSRD model is based on the open‐population robust design model (Kendall & Bjorkland, 2001) and the multistate Jolly–Seber superpopulation model (Kéry & Schaub, 2012). However, in contrast to the open‐population robust design model of Kendall and Bjorkland (2001), the JSRD assumes population closure within primary occasions (Gibson et al., 2018). Within primary capture periods, we modelled detection probability as being constant across individuals and over time (corresponding to the model M 0 in classical closed CR models; Otis et al., 1978).…”

“…We fitted the JSRD model to CR data using the parameterization that follows an individual‐level observation process (i.e. using the code provided in Data S3 in Gibson et al., 2018) through JAGS using the same MCMC settings described above. The code to reproduce this analysis is provided in Supporting Information.…”

Stopover Ecology of Red Knots in Southwestern James Bay During Southbound Migration

“…Juveniles make up a substantial component (>10%) of red knot observations in James Bay, and previous population estimators from other fall staging sites (Lyons et al 2017, 2018) have not explicitly accounted for the time‐dependent (and always unmarked) proportion of juvenile red knots. Gibson et al (2018) included age ratios in an integrated Bayesian analysis to estimate age‐specific abundances of American oystercatchers ( Haematopus palliatus ). We used a similar strategy in the third component of our integrated analysis to model the proportion of adult red knots in the passage population.…”

Hurricane Sandy and engineered response created habitat for a threatened shorebird

“…Thus, more coastal flooding and erosion are predicted (Wong et al 2014). While hurricanes and storms can harm (Marsh and Wilkinson 1991, Brown and McLachlan 2002, Sheikh 2005 or induce temporary emigration (Gibson et al 2018a) in organisms, disturbance has long been recognized as a key driver of patterns and processes in natural ecosystems (Turner 2010), and it is unlikely that all hurricane-driven changes are negative.…”