Chironomid Emergence and Relative Emergent Biomass from Two Alabama Streams

Abstract

Chironomid pupal exuviae were sampled monthly using drift nets and hand sieves over an annual cycle from Hendrick Mill Branch (HMB; Blount County, AL) and Payne Creek (PC; Hale County, AL). Taxon richness, community composition, and emergence phenologies were similar despite marked differences in physical/chemical characteristics of the study streams. The highest emergence rates were observed in spring (PC) or both spring and fall (HMB). However, there was no significant relationship between emergence/emergent biomass and date. Estimates of daily emergence and emergent biomass were much higher in HMB than in PC. These patterns may have resulted from a more consistent flow regime, higher substrate stability, lower variation in temperature/chemical characteristics, greater channel surface area, and a more significant hyporheic zone in HMB than in PC.