Size structure and distribution of predatory aquatic insects among mesoscale hydraulic habitats

This research examines how mesoscale streamflow dynamics can filter aquatic insect communities based on their trait expression. As water levels change seasonally, depth and velocity fluctuate within the channel. Invertebrates select these mesoscale habitats based in part on their physiological requirements. Therefore, the environment is a strong selective force acting on organismal traits to determine site-level taxonomic composition. We use high-resolution habitat data including, depth, average and bed velocity, shear stress, and Froude number collected in conjunction with invertebrate sampling in the Miramichi River in New Brunswick, Canada in July and September 2010 to investigate flow-environment relationships for five orders of aquatic insects (Ephemeroptera, Plecoptera, Trichoptera, Odonata, and Megaloptera). Here, we focus on the distribution of predatory invertebrates and their potential to interact with other invertebrates within mesoscale habitat patches. Predators also demonstrate the greatest magnitude of growth, which will be tracked over time. By mapping the movements and morphological characteristics of invertebrates, particularly predators, we can better understand their habitat requirements throughout their development - a necessary component for establishing connections to larger-scale hydrologic processes and environmental flow regulations