COS 88-4 - Plant-pollinator phenological synchrony along a dryland elevational gradient

Abstract: As climate change alters temperature and precipitation patterns, species are responding spatially and phenologically in order to maintain historical niches and interspecific interactions. Plants and pollinators require spatiotemporal synchrony for successful pollination, which is essential to ecosystem functioning through the role of plant reproduction. While studies have examined plant-pollinator spatiotemporal responses to climate change in temperate, high elevation, and high latitude ecosystems, little is understood about plant-pollinator interactions along climatic gradients in dryland ecosystems. In this study, we analyzed two years of plant-pollinator interaction data collected at five sites along an elevational gradient (700ft – 8000ft) in the San Bernardino National Forest, California, in 2021 and 2022. Floral phenology data and plant-pollinator interactions were collected weekly for the duration of the field season along the gradient (February – August). We analyzed floral, pollinator, and plant-pollinator phenological synchrony at each site to determine how elevation and climate impacts plant-pollinator interactions. We found that phenological synchrony improved with elevation from the plant perspective due to increased pollinator richness, while phenological synchrony from the pollinator perspective improved with elevation due to floral duration increasing. These results indicate that plant-pollinator phenological synchrony is weakest at low elevations, where drought and high temperatures are having the greatest impact. This is one of the first studies to examine plant-pollinator phenological synchrony along an elevational gradient in a dryland ecosystem.