Community context mediates effects of pollinator loss on seed production

A critical goal for ecologists is understanding how ongoing local and global species losses will affect ecosystem functions services. Diversity–functioning relationships, which are well-characterized in primary producer communities, much less consistently predictable involving two or more trophic levels, particularly situations where multiple one level impact functional outcomes at another level. This relevant to pollination functioning, given pollinator declines the value of functioning single plant like crops threatened plants. We used spatially replicated, controlled single-pollinator-species removal experiments assess changes bumble bee richness impacted production fertilized seeds a perennial herb—Delphinium barbeyi—in Rocky Mountains Colorado, USA. To improve predictability, we also assessed traits abundances communities were related D. barbeyi reproductive success. hypothesized that trait-matching between proboscis length barbeyi's nectar spurs would produce greater number seeds, while morphological similarity within floral community dilute found effects differed depending on behavioral patterns pollinators compositional features communities. While fidelity generally increased seed production, positive effect was primarily evident when than half Bombus experimentally removed. Similarly, comprising long-tongued bees most beneficial tandem with strong removal. Finally, observed contrasting community, evidence both competition facilitation among These results offer an example complex dynamics underlying function multitrophic systems demonstrate context can diversity–functioning relationships levels.