Ephemeropteran community structure and spatial stability of local populations of the major species group in the Keumho River

Abstract

AbstractThis study was conducted to analyze the community structure of mayflies and stabilizing points for the local populations in relation to longitudinal changes in the Keumho River, Korea. A total of 22 ephemeropteran species occurred in the main riverine system during the sampling period of 3 years. The results indicated that Baetis fuscatus (mean density of 117.3 individuals/m2), Ecdyonurus levis (54.1), Uracanthella rufa (51.3) and Caenis KUa (49.9) comprised the major species group of the ephemeropteran community. The results of statistical analyses showed that these four species were distinguished from the others in terms of their mean densities. Longitudinal patterns based on total species numbers and numbers of individuals were characterized into three phases. A new approach was applied to analyze stabilized points for local populations based on the River Continuum Concept and density‐dependent mechanisms among local populations in a metapopulation. Stabilized local populations of B. fuscatus and E. levis occurred coincidentally at two points that were approximately 45 and 75 km away from the Youngchun Dam. Caenis KUa was locally stabilized at two points that were 40 and 60 km away from the dam. Uracanthella rufa showed only one stabilized local population at a point approximately 80 km away from the dam. The diversity index for the ephemeropteran community was compared with that calculated for the benthic macroinvertebrate community, and their similarity is discussed.