Quantifying spatial variation in the size and structure of ecologically stratified communities

2. We provide a novel hierarchical multi-region community model that allows for direct modelling of trait-based patterns of species richness along environmental gradients by partitioning communities into ecologically relevant strata (e.g. guilds). We illustrate the flexibility of the model by simulations, where we estimate guild richness and community composition using both categorical and continuous species traits. In addition, we apply our model to data from eight avian communities to explore how guild richness varies across elevational gradients.

1. Including ecological specialization (e.g. functional guild) in analyses performed across regions can help to study how size and structure of communities vary across environmental gradients. Multi-species occupancy models, and their extension to a multi-region framework, represent useful tools for such gradient analysis based on functional traits. However, in these models species richness is only a derived parameter and therefore explicit relationships cannot be inferred.