Plant and bee responses to climate change

For my post-doctoral research, I am addressing questions about how flowering plants and bees are responding to climate variation, and potential consequences for their populations.

I am working with David Inouye who has a unique on-going dataset, going back to 1973, on the flowering phenology and abundance of many subalpine meadow plant species at the Rocky Mountain Biological Laboratory in Colorado, USA. Along with Brian Inouye and Nora Underwood, we are examining how the community composition of flowers has changed through time, and how this is influenced by climate variation. Can we predict what the community will look like given continued warming and earlier snowmelt? We are also interested in the individual-level responses that make up the population, and ultimately community, responses of plants.

Very little is known about the long-term abundance and phenology of bees and their relationships to climate and floral resource variation. I am focusing on bumble bees, who are abundant pollinators in temperate, alpine, and arctic regions of the Northern Hemisphere. First, I am addressing how the foraging behaviour of bumble bees might respond to climate-driven changes in flower abundance. When floral resources are low, which tends to occur when it is warm and the snow melts earlier, do bumble bees visit a wider array of flower types? If so, this may bode well for their population persistence.

Second, along with Becky Irwin and Sean Griffin, we are using an eight-year dataset on bee abundance to address how bumble bee population sizes are influenced by variation in flowers and climate. Third, along with Hollis Woodard and David Inouye, we are examining the phenology of bumble bee queens and how their nesting success depends on flower availability and timing. Queens are a critical but understudied life stage for bumble bee colonies: they experience high demands under harsh conditions, yet they solely contribute to the abundance of worker and reproductive bees later in the season.

Linking pollinator foraging behaviour to pollination

For my Ph.D. (advised by James Thomson), I investigated how characteristic pollinator responses to plant communities can affect plant pollination in novel but important ways. I focused on how pollinator foraging behaviour can affect plant pollination over broader spatial and temporal scales than researchers typically examine.

I looked at the typical distances that individual bumble bees forage over and may influence plant reproductive success, and some idiosyncratic bumble bee behaviours that may cause one plant species to increase the pollination of another. To approach these questions, I used a combination of experimental and observational field studies on Delphinium barbeyi (subalpine larkspur, Ranunculaceae) and three late blooming gentians (Gentianaceae), and their shared long-tongued bumble bee pollinators, in subalpine meadows near the Rocky Mountain Biological Lab. I often uniquely marked individual bumble bees to see where they foraged over time. It turns out that what individual bees do can affect plant pollination over broad spatial and temporal scales!

Other research

I am interested in the pollination role of male bumble bees for late season flowering plants, as they are typically not considered important pollinators but can be common on flowers at this time. In addition, I am collaborating with Jessica Forrest, investigating potential adaptive explanations for the variation in style length of a spring-flowering herb, Mertensia fusiformis (Boraginaceae). I also share a rare interest in what individual pollinators do with Takashi Makino, and we are collaborating on this topic.