Pollinators assist 80 percent of flowering plants in their reproduction, which accounts for much of the food ingested by humans and wildlife. The worldwide decline in pollinators highlights the importance of understanding factors affecting plant-pollinator interactions. We examined how drought, which is predicted to increase in the Western United States due to climate change, affected floral odors and pollinator attraction in four plant species in Montana.
Drought stress reduced pollinator visitation to three of the four plant species and altered floral scent in all four plant species we studied in Montana. For example, drought-stressed bluebells (Campanula rotundifolia) lacked certain floral odors and received only one-quarter of the pollinator visits when compared to well-watered plants. Drought also negatively affected pollinator visitation to hairy golden aster (Heterotheca villosa) and silverleaf phacelia (Phacelia hastata).
Our findings suggest that some plants and pollinators will be negatively affected if the frequency and severity of droughts increase due to climate change. Knowledge about how drought will affect pollination and which plants are most likely to be affected is needed to successfully manage and restore native ecosystems.