A multivariate approach reveals diversity of ontogenetic niche shifts across taxonomic and functional groups

Shifts in the fundamental and realize niche of individuals during their ontogeny are ubiquitous in nature, but we know little about what aspects of the niche change and how these changes vary across species within communities. Yet, this knowledge is essential to predict the dynamics of populations and communities and how they respond to environmental change. Here I introduce a range of metrics to describe different aspects of shifts in the realized trophic niche of individuals based on stable isotopes. Applying this multi-variate approach to 2,272 individuals from 13 taxonomic and functional distinct species (Amphibia, Hemiptera, Coleoptera, Odonata) sampled in natural pond communities allowed me to: (1) describe and quantify the diversity of trophic niche shift patterns over ontogeny in multi-dimensional space, and (2) identify what aspects of ontogenetic shifts vary across taxa, and functional groups. Results revealed that species can differ substantially in which aspects of the troph...