Lilies at the limit: Variation in plant-pollinator interactions across an elevational range

Area of Science:

• Ecology
• Plant Biology
• Conservation Biology

Background:

• Species distribution is often attributed to climate, but biotic interactions like pollination can also be limiting factors.
• Pollinator limitation may restrict species' ranges by reducing reproductive output at range margins.

Purpose of the Study:

• To investigate the influence of pollinators on the altitudinal distribution of Erythronium montanum.
• To determine if seed production relies on pollinators and if pollen limitation varies with range limits.
• To assess if pollinator visitation patterns correlate with seed production and pollen limitation.

Main Methods:

• A three-year study was conducted on Erythronium montanum at Mount Rainier National Park.
• Assessed pollinator reliance for fruit set and pollen limitation across altitudinal range limits.
• Monitored insect visitation rates and pollinator composition in relation to seed production patterns.

Main Results:

• Erythronium montanum relies on pollinators for fruit set.
• Pollen limitation showed a trend towards higher levels at the upper range limit in some years.
• Pollinator visitation rates did not consistently reflect spatial patterns of pollen limitation, with bumblebees potentially being more effective pollinators than syrphid flies.

Conclusions:

• Pollinators are crucial for the reproductive success of this wildflower.
• Plant-pollinator interactions do not appear to be the primary driver of Erythronium montanum's distribution.
• Spatio-temporal variability in plant-pollinator dynamics may influence species' responses to climate change.