title: Seasonal dynamics of the fish assemblage in a floodplain lake at the confluence of the Negro and Amazon Rivers.
abstract: The temporal effect of discharge and limnology on fish composition and species diversity in a floodplain lake at the confluence of the Amazon and Negro Rivers was evaluated. Species richness, abundance and assemblage composition were strongly influenced by seasonal discharge of the Amazon and Negro Rivers, which affects lateral connectivity, water conductivity and temperature. As a consequence, temporal β-diversity was high in the lake and the assemblage was dominated by seasonally transient species. Relatively large species known to feed on resources within the floodplain were captured almost exclusively during the flood period. During the dry season, the assemblage was dominated by fishes adapted to harsh conditions of high temperature and low dissolved oxygen concentrations. An open system with high spatial and temporal heterogeneity created by the meeting of two large rivers with different water chemistry, Lago Catalão has a dynamic fish assemblage. Given its high temporal β-diversity and abundance of fishes, many of great importance in local fisheries, Lago Catalão and other floodplain lakes in this region merit special attention for conservation.
authors.affiliation: Programa de Pós-Graduação em Biologia de Água Doce e Pesca Interior, Instituto Nacional de Pesquisas da Amazônia - INPA, Cx. Postal 2223, 69080-971, Manaus, Amazonas, Brasil.
authors.forename: C P
authors.initials: CP
authors.lastname: Röpke
authors.affiliation: Coordenação de Biodiversidade, CBIO/Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Amazonas, Brasil.
authors.forename: S A
authors.initials: SA
authors.lastname: Amadio
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843-2258, U.S.A.
authors.forename: K O
authors.initials: KO
authors.lastname: Winemiller
authors.affiliation: Coordenação de Biodiversidade, CBIO/Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Amazonas, Brasil.
authors.forename: J
authors.initials: J
authors.lastname: Zuanon
mesh_terms: D000818:Animals; D001938:Brazil; D017753:Ecosystem; D005399:Fishes; D055868:Floods; D060106:Lakes; D045483:Rivers; D012621:Seasons
keywords: Lago Catalão; flood pulse; hydrology; multivariate ordination; neotropics; β-diversity