Phenology varies with phylogeny but not by trophic level with climate change

Abstract

Shifts in phenology with climate change can lead to asynchrony between interacting species, with cascading impacts on ecosystem services. Previous meta-analyses have produced conflicting results on whether asynchrony has increased in recent decades, but the underlying data have also varied-including in species composition, interaction types and whether studies compared data grouped by trophic level or compared shifts in known interacting species pairs. Here, using updated data from previous studies and a Bayesian phylogenetic model, we found that species have advanced an average of 3.1 days per decade across 1,279 time series across 29 taxonomic classes. We found no evidence that shifts vary by trophic level: shifts were similar when grouped by trophic level, and for species pairs when grouped by their type of interaction-either as paired species known to interact or as randomly paired species. Phenology varied with phylogeny (λ = 0.4), suggesting that uneven sampling of species may affect estimates of phenology and potentially phenological shifts. These results could aid forecasting for well-sampled groups but suggest that climate change has not yet led to widespread increases in phenological asynchrony across interacting species, although substantial biases in current data make forecasting for most groups difficult.