Emergence of Aquatic Insects from 2 Habitats in a Small Wetland of the Southeastern USA: Temporal Patterns of Numbers and Biomass

Abstract

Emergence of aquatic insects from freshwater systems can provide information that is useful from both taxon-specific and ecosystem perspectives. Although numerous studies of emergence have been conducted in high-latitude systems, relatively few studies have been done in warm-water systems, particularly in wetlands, where multiple generations and long emergence periods are likely. We used emergence traps in a small beaver-impounded wetland in the southeastern USA to measure density and biomass of emerging insects, and deposition basins to measure adult return and potential export from the system. We focused on 2 major habitats of the wetland: a shallow (0-1.0 m) vegetated zone dominated by the white water-lily Nymphaea odorata and a deeper (>1 m) open-water zone. Insects (primarily Chironomidae) emerged from the Nymphaea zone throughout the year, but peaked in April at 205 individuals·m -2 · d -1 and then declined from mid June to November to 20-50· m -2 · d -1 . Emerge...