title: Impact of flood events on macrobenthic community structure on an intertidal flat developing in the Ohta River Estuary.
abstract: We investigated the effects of river floods on the macrobenthic community of the intertidal flat in the Ohta River Estuary, Japan, from 2005 to 2010. Sediment erosion by flood events ranged from about 2-3 cm to 12 cm, and the salinity dropped to 0‰ even during low-intensity flood events. Cluster analysis of the macrobenthic population showed that the community structure was controlled by the physical disturbance, decreased salinity, or both. The opportunistic polychaete Capitella sp. was the most dominant species in all clusters, and populations of the long-lived polychaete Ceratonereis erythraeensis increased in years with stable flow and almost disappeared in years with intense flooding. The bivalve Musculista senhousia was also an important opportunistic species that formed mats in summer of the stable years and influenced the structure of the macrobenthic community. Our results demonstrate the substantial effects of flood events on the macrobenthic community structure.
authors.affiliation: Environmental Research and Management Center, Hiroshima University, 1-5-3, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513, Japan. Electronic address: wataru@hiroshima-u.ac.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Nishijima
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakai
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Okuda
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Imai
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Okada
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000145:classification* / Q000254:growth & development; D044822:Biodiversity; D004784:Environmental Monitoring; D063366:Estuaries; D055868:Floods; D019015:Geologic Sediments / Q000737:chemistry*; D007448:Invertebrates / Q000145:classification* / Q000254:growth & development; D007564:Japan; D011077:Polychaeta / Q000145:classification / Q000254:growth & development; D045483:Rivers / Q000737:chemistry
keywords: Estuary; Flood; Intertidal flat; Macrobenthic community; Opportunistic species; Salinity stress