High Arctic plants show independent responses to pollination and experimental warming

Abstract

Arctic plants will experience both higher temperatures and changes to their pollination regime under future climate change scenarios. However, reproductive responses to pollination, warming, and a pollination–warming interaction likely vary with seasonal timing in phenology, and may be more pronounced in early-flowering plants than later-flowering plants. To test these hypotheses, we applied hand pollination and exclusion treatments to three Arctic plant species (early-flowering Salix arctica Pall., mid-season flowering Dryas integrifolia Vahl, and late-flowering Papaver radicatum Rottb.) inside and outside of open-top chambers (OTCs), to determine how pollination and warming may interact. We found that OTCs did not significantly reduce visitation by insects, nor did they reduce seed production in wind-pollinated S. arctica. Flower production and seed germination rates for D. integrifolia matched the predictions for warmth- and pollen-limited plants. Reproduction in P. radicatum did not respond strongly to either warming or pollination. Overall, we found that High Arctic plant reproduction is affected independently by pollination and OTC warming, indicating that plant responses to ongoing increases in temperature will not be strongly altered by changes in insect pollination.