Timing matters: phenological constraints and predation shape Arctic community structure

Top-down and bottom-up controls of animal populations are key elements of niche and coexistence theories, but there is still little empirical evidence on how these forces determine species distribution and community assemblies. In Arctic ecosystems, spring snowmelt sets the timing and duration of the snow-free period, thereby controlling food availability, while predation often imposes additional constraints on prey species. The relative importance of these abiotic and biotic filters on distribution is also susceptible to vary with body size. Using 10 years of high-resolution data on all major members of an Arctic vertebrate community and their shared predator, we tested how snowmelt timing