The impact of climate change on insect-mediated nutrient cycling in the Arctic tundra

The Arctic is warming at four times the rate of the global average, with significant potential consequences for the invertebrates that are uniquely adapted to the harsh environment of the Arctic tundra. One notable impact of climate warming in the Arctic is the thawing of the permafrost, which is increasing nutrient availability in the active layer of the soil. We wanted to understand how nutrient availability might impact invertebrate herbivory on Arctic shrubs. We conducted a survey of herbivory damage on the dwarf birch (Betula nana) across a long-term fertilisation gradient at Toolik Field Station in Alaska. We found that nutrient inputs significantly impacted the amount of leaf area removed by invertebrate herbivores. We paired this survey with a controlled study of caterpillar herbivory - preliminary results suggest that the nutrient content of leaf tissue significantly impacts the amount of biomass consumed by herbivores in the Arctic, with potential consequences for carbon sequestration under future climate warming.