Trabajo completo en oral y resumen en libro. Gradiente de doble inestabilidad en el río Paraná Medio: análisis de un patrón ecológico utilizando rasgos biológicos

FLORENCIA L. ZILLI,; SAIGO M; MARCHESE MERCEDES ROSA; LUCIANA MONTALTO

Congreso; 1er Congreso Iberoamericano de Limnología XIII Congreso de la Sociedad Chilena de Limnología Valdivia, 1 al 4 de noviembre de 2016 L; 2016

Environmental stability is a key property of ecosystems because it sets the prevalence of biological or physicaldeterminants of community structure. We hypothesize that in large floodplain rivers there are two oppositeinstability gradients. The hydrologic instability gradient, which is high in temporarily connected lakesand low in permanently, connected lakes and rivers. The sand bed instability that is high in main channelswhere hydraulic forces cause the permanent movement of sand dunes, and low in small rivers and lakes.In the present study we tested three hypotheses H1: Inter-specific competition structures communities inpermanently connected lakes and small rivers, H2: In large rivers communities are not structured by competitionbut by sand bed instability. H3: In temporarily connected lakes communities are not structured bycompetition but by hydrologic instability. We sampled benthic invertebrates in 30 sites of the Middle ParanáRiver-floodplain system, analyzed co-occurrence patterns and traits-type of site relationship by RLQ andfourth corner method. We performed an RLQ analysis to show the relationship between site type (R matrix)and traits (Q matrix) by means of species abundances per site (L matrix). Observed co-occurrence patternswere according to the hypotheses. Similarly, there was a global significant relationship between traits andtype of sites (p