A Comment on Priors for Bayesian Occupancy Models

Authors

Joseph Northrup
Brian D. Gerber, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

2-26-2018

Abstract

Understanding patterns of species occurrence and the processes underlying these patterns is fundamental to the study of ecology. One of the more commonly used approaches to investigate species occurrence patterns is occupancy modeling, which can account for imperfect detection of a species during surveys. In recent years, there has been a proliferation of Bayesian modeling in ecology, which includes fitting Bayesian occupancy models. The Bayesian framework is appealing to ecologists for many reasons, including the ability to incorporate prior information through the specification of prior distributions on parameters. While ecologists almost exclusively intend to choose priors so that they are “uninformative” or “vague”, such priors can easily be unintentionally highly informative. Here we report on how the specification of a “vague” normally distributed (i.e., Gaussian) prior on coefficients in Bayesian occupancy models can unintentionally influence parameter estimation. Using both simulated data and empirical examples, we illustrate how this issue likely compromises inference about species-habitat relationships. While the extent to which these informative priors influence inference depends on the data set, researchers fitting Bayesian occupancy models should conduct sensitivity analyses to ensure intended inference, or employ less commonly used priors that are less informative (e.g., logistic or t prior distributions). We provide suggestions for addressing this issue in occupancy studies, and an online tool for exploring this issue under different contexts.

Citation/Publisher Attribution

Northrup JM, Gerber BD (2018) A comment on priors for Bayesian occupancy models. PLOS ONE 13(2): e0192819. https://doi.org/10.1371/journal.pone.0192819

Available at: https://doi.org/10.1371/journal.pone.0192819

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Comment

A correction to this article was published in 2019 and is available in the "Additional Files" section with a downloadable PDF.

Citation Information:

Northrup JM, Gerber BD (2019)
Correction: A comment on priors for Bayesian
occupancy models. PLoS ONE 14(2): e0212346. https://doi.org/10.1371/journal.pone.0212346