Three-dimensional models for animal movement and habitat selection

Animal movement and habitat selection underpin important ecological phenomena, from individual behaviour to population-level distributions. Despite navigating three-dimensional space, the spatial locations of animals are often measured and analysed on a two-dimensional plane, which limits our understanding of species that swim or fly. In this talk, I will describe how step selection functions (SSFs) can be adapted to quantify animal movement and habitat selection in three dimensions. Using Antarctic petrel data, I will illustrate how these three-dimensional SSFs can be used to assess selection for vertically-stratified habitat, account for barriers (e.g., the ground or ocean surface), and model attraction to any number of directional targets. I will also discuss some current works and future directions related to addressing unresolved needs in three-dimensional movement modelling. We hope these new statistical developments will provide a solid foundation for three-dimensional analyses aimed at answering ecological questions that may otherwise be ignored in two dimensions.