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

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.