Response of Forest Insects and their Natural Enemies to Simulated Ice Storm Damage in Northern Hardwood Forests

Large-scale disturbances such as ice storms are likely to increase in frequency and intensity as climate changes. While disturbances are a natural component of forest ecosystems, climatically driven alteration may impart fundamental change to ecosystem function. A novel experiment at Hubbard Brook Experimental Forest, NH, will apply simulated ice storms of varying severity and frequency to replicate northern hardwood plots to develop an empirical understanding of their effects on forests. As part of this experiment, I will quantify effects of ice storm treatments on wood-boring beetles and leaf-feeding Lepidoptera (caterpillars), the most important herbivores in temperate forests. Not only do these groups contain many economically important pest species, collectively they perform vital ecosystem services such as nutrient cycling and decomposition. These insects also facilitate competitive interactions among tree species and contribute to stand productivity. Their natural enemies, including ants, wasps, and birds, help keep insect populations in check. As such, understanding dynamics of these groups after ice storms will aid in forest management and conservation. To assess responses to ice storm damage, I will trap adult and larval wood-boring beetles and their invertebrate natural enemies. Through deployment and retrieval of plasticine model caterpillars, I will estimate bird and invertebrate predation from characteristic ‘wounds’ to the surrogates. Insectivorous bird species will be measured using point counts. At this point, I am presenting baseline data regarding predation rates, bird diversity, and adult beetle diversity. Following ice storm damage, I expect that beetles and their natural enemies will increase in abundance and diversity, while caterpillar predation events and their avian predators will increase after mild ice storms but decrease after more extreme storms.