Shifting spring ephemeral pollination windows under climate change - a three-body problem.

Potential and realized climate change-driven phenological mismatches have been reported across a variety of pairwise species' interactions. However, species often engage in more than one type of temporally structured interaction - therefore, the consequences of phenological shifts must be evaluated in this context. Synthesizing data from natural history collections, community science initiatives, and remote-sensing platforms, we analyzed the phenology of the flowering of an understory spring ephemeral species, the emergence of its specialist pollinator, and the closure of the canopy above. We determined how variation in phenological responses to climate across these interacting guilds impacts the potential pollination window of the spring ephemerals. We demonstrate that phenological responses to climate change can vary greatly among the three guilds across their interacting range. The potential pollination window was predicted to undergo divergent shifts among ecoregions across the landscape in the near future, which can impact the fitness and reproductive success of both flowers and pollinators. Our study represents a first step toward integrating phenological knowledge across multiple interacting guilds. Expanding such efforts will be critical to improving our ability to predict how ecosystems, communities, and the ecological interactions therein will be impacted by global change.