%0 Journal Article
%T Effects of the interannual variations in the flood pulse mediated by hypoxia tolerance: the case of the fish assemblages in the upper Paran芍 River floodplain
%A Ana Cristina Petry
%A Fabiane Abujanra
%A Luiz Carlos Gomes
%A Hor芍cio Ferreira Julio Julio Jr.
%J Neotropical Ichthyology
%D 2013
%I Sociedade Brasileira de Ictiologia
%X The effects of the duration of the floods on abiotic variables and attributes of species tolerant and intolerant to hypoxia (STH and SIH respectively) were evaluated in rivers and lakes of the upper Paran芍 River. Fish were sampled once a year, in six sampling stations, during the high water period from 2000 to 2003. There were overall reductions in dissolved oxygen levels and increases in transparency of water in lakes in years of moderate floods. The duration of floods influenced species differentially based on their tolerance to hypoxia: in moderate floods, richness of STH increased and numerical abundance and biomass of SIH reduced significantly. Opposite relationships were detected between dissolved oxygen and the attributes of STH and SIH. Dissolved oxygen was the best predictor of variability of STH and SIH in years of moderate floods, whereas water transparency predicted significant amounts of STH in years of short floods. Being positively affected by dissolved oxygen reductions, STH seem to take advantages in persisting in seasonally harsh lentic habitats. The incorporation of abiotic data as well the differential tolerance of species to hypoxia would improve further investigations of the effects of interannual variations in the flood pulse on tropical fish assemblages Os efeitos da dura  o da cheia sobre algumas vari芍veis abi車ticas e atributos das assembleias de peixes (esp谷cies tolerantes e intolerantes 角 hip車xia, STH e SIH, respectivamente) foram avaliados em rios e lagoas do alto rio Paran芍. Os peixes foram amostrados uma vez ao ano, em seis localidades, durante o per赤odo de 芍guas altas entre 2000 e 2003. Houve redu  es generalizadas nos n赤veis de oxig那nio dissolvido e aumentos na transpar那ncia da 芍gua em lagos em anos de cheias moderadas. A dura  o das cheias influenciou as esp谷cies diferencialmente em fun  o de sua tolerancia 角 hip車xia: em anos de cheias moderadas, a riqueza das STH aumentou e a abundancia num谷rica e de biomassa das SIH reduziram significativamente. Rela  es opostas foram detectadas entre o oxig那nio dissolvido e os atributos das STH e SIH. O oxig那nio dissolvido foi o melhor preditor da variabilidade de STH e SIH em anos de cheias moderadas, enquanto a transpar那ncia da 芍gua explicou uma significativa propor  o das STH em anos de cheias curtas. Por serem positivamente afetadas pelas redu  es no oxig那nio dissolvido, as STH parecem ter vantagens em persistir em ambientes l那nticos sazonalmente in車spitos. A incorpora  o de dados abi車ticos bem como da tolerancia diferencial das esp谷cies 角 hip車xia deve aprimorar as investiga  es d
%K Dissolved oxygen
%K Duration of floods
%K Lakes and rivers
%K Neotropical
%K Water transparency
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252013005000813