COS 205-3 - Community phenology of arctic plants and their pollinators: a resource-consumer mismatch?

Abstract: For plants and pollinators to interact, they must meet in time. To what extent the progression of pollinators matches the availability of flowers across the arctic season is poorly known – with recent suggestions of a rift between flower and pollinator phenology. This study aims to characterize the community phenology of flowers and insects from both a descriptive and functional perspective. First, we characterize species-specific phenology among plants and insects, and second, we use information on to characterize the actual supply and demand for pollinator services vs flower resources during different parts of the summer. To record the phenology of flowering resources, we recorded the flowering stage of all 41 plant species occurring in four ecotypes at the Canadian High Arctic Research Site (CHARS) in Cambridge Bay, Nunavut, in weekly intervals. To characterize pollinator phenologies, we generated weekly insect samples by a Malaise trap set at each site, and by the use of sticky mimics of Dryas octopetala flowers. Insect sampling continued well after flowering was over. By combining these data on species phenologies with network-level data on what plants interact with what pollinators, we characterize both community-level phenology of insects and plants, and the seasonal dynamics of supply and demand for each flower resource. Based on time-series analyses from other arctic sites, we predict that the peak supply of flower resources will precede their peak demand by flower-visiting pollinators. At the time of writing, the data are still being analyzed. Preliminary results suggest that pollinator abundances are highest two weeks after the last flowers have bloomed. Such a lag between flower resource availability and peak pollinator densities implies a hunger gap for pollinators. Consequently, this mismatch will have important implications for plant pollination, pollinator fitness and the future of the arctic ecosystem.