The poisson log-normal model: A generic framework for analyzing joint abundance distributions

In this chapter, the authors illustrate the possibilities offered by the Poisson log-normal (PLN) model using marine species count data collected by the PISCO research program. Statistical models have been designed to respond to the limits, focusing on associations between species and their joint reaction to the environment. The presence-absence or abundance of all the species in question are also modeled jointly. The resulting models are known as joint species distribution models and are notably different from species abundance models, which consider the influence of the environment on the abundance of a single species. The authors also use the MariNet dataset, extracted from the PISCO data, to show how the PLN model may be used in response to three types of questions: evaluating the influence of covariates, such as site or year, on species abundance; identifying species which react to these covariates in the same way; and identifying direct interactions between species.