Arctic insect emergence timing and composition differs across thaw ponds of varying morphology

Abstract

Freshwater ponds provide habitats for aquatic insects that emerge and subsidize consumers in terrestrial ecosystems. In the Arctic, insects provide an important seasonal source of energy to birds that breed and rear young on the tundra. The abundance and timing of insect emergence from arctic thaw ponds is poorly understood, but understanding these fluxes is important, given the role of insects in food webs and current rates of environmental change at high latitudes. We aimed to evaluate emerging insect communities from thaw ponds with different morphologies, identify environmental covariates influencing insect composition, and describe temporal changes in insect abundance. We collected environmental information and insects that emerged over two growing seasons and examined the phenology and taxonomic composition of insects arising from different pond classes: low centered polygon, small coalescent, large coalescent, and trough ponds. Our findings indicated no differences in the timing of total emergence across ponds of varying morphology. Community dissimilarity was primarily associated with center or margin habitat and variables that differed strongly among pond classes. These insects, which provide important provisions for various species of birds, are likely to experience changes in emergence phenology and composition due to ongoing, rapid warming in the region.