Recently accumulated evidence has documented a climate impact on the demography and
dynamics of single species, yet the impact at the community level is poorly understood.
Here, we show that in Svalbard in the high Arctic, extreme weather events synchronize
population fluctuations across an entire community of resident vertebrate herbivores and
cause lagged correlations with the secondary consumer, the arctic fox. This synchronization
is mainly driven by heavy rain on snow that encapsulates the vegetation in ice and blocks
winter forage availability for herbivores. Thus, indirect and bottom-up climate forcing
drives the population dynamics across all overwintering vertebrates. Icing is predicted to
become more frequent in the circumpolar Arctic and may therefore strongly affect
terrestrial ecosystem characteristics.
