Assistant Professor of Biology University of California, Riverside, California, United States
Background/Question/Methods
Climate change-induced phenological asynchrony has the potential to disrupt species interactions through asymmetric shifts between historically interacting species. Studies between plants and pollinators have shown variable degrees of phenological asynchrony, with mismatches being uncommon. However, previous studies have focused on temperate systems and often use phenological summaries to determine phenological asynchrony rather than considering species’ entire phenological distributions. Here, we quantify the overlap in phenological distributions between 13 flowering plants and their bee guilds between 2002-2015 at the Sevilleta National Wildlife Refuge, NM, US. We used beta-distribution generalized linear mixed models to determine how plant-bee phenological synchrony was changing over time, the influence of phenological shifts in driving phenological synchrony, and the impact of climate on phenological synchrony.
Results/Conclusions
We found that plant-bee phenological synchrony overall has not decreased over time. Only one of 12 specialist bees, one of 17 generalist bees, and one of 13 plants species are significantly decreasing in phenological synchrony during the 14-year time series. Phenological synchrony decreased as phenophase onset, peak, and senescence shifted apart between interacting species. However, the difference in phenological onset, peak, and senescence did not change over time. Phenological synchrony was not affected by changes in aridity.
These results indicate that plant-bee phenological synchrony is generally consistent or increasing at the Sevilleta National Wildlife Refuge. Despite shifts in phenological distributions between years, plants and bees are maintaining their phenological synchrony. While some species are at risk of a phenological mismatch if they continue losing synchrony with their interacting partners, most species have sustained phenological synchrony. These results are the first long-term examination of plant-pollinator phenological synchrony in the arid southwest and indicate the potential for the resilience of pollination in the region.
