Guido AyalaKarina ZambranaMabel Maldonado2026-03-222026-03-222000https://andeanlibrary.org/handle/123456789/60089Citaciones: 1TROPHIC STRUCTURE OF THE ICHTHYOCOENOSIS IN SHALLOW LAKES OF THE FLOODPLAIN OF THE ICHILO AND CHAPARE RIVERS (BOLIVIA) Se estudio la estructura trofica de la ictiofauna de cuatro lagunas de la varzea de los rios Ichilo y Chapare (Departamentos de Cochabamba y Santa Cruz; 16005' a 16°43'S y 64°48' a 64°72'W) mediante el analisis estomacal de 1111 ejemplares pertenecientes a 52 especies y capturados en cuatro fases hidrologicas de los anos 1994 y 1995. Se utilizo un indice alimentario para agrupar las especies, definiendose cuatro grandes categorias troficas: carnivoros, herbivoros, omnivoros y detritivoros. Los grupos mas variados en numero de especies fueron los omnivoros y carnivoros, en tanto que en numero de individuos fueron dominantes los carnivoros que representaron algo mas del 50% de la abundancia total, les siguieron los omnivoros y los detritivoros, siendo los menos abundantes los herbivoros. El analisis temporal y espacial de la estructura trofica mostro que las variaciones entre lagunas son poco notorias, mostrandose mas importantes las variaciones entre fases hidrologicas, que basicamente implican un aumento en la proporcion de herbivoros durante la fase de inundacion. Se presenta una red trofica para las lagunas, que tampoco mostro variaciones importantes ni entre lagunas ni entre fases hidrologicas. Estos resultados sugieren que la estructura trofica de estas lagunas seria diferente a las descritas para grandes rios de la Amazonia y de otras cuencas sudamericanas, debido a una menor importancia de las especies detritivoras, herbivoras y omnivoras frente a las carnivoras, ya una relativa estabilidad de la estructura frente a los cambios hidrologicos asociados a un pulso de inundacion corto y poco predecible. Palabras claves: Estructura trofica, redes troficas, peces, rio Ichilo, rio Chapare, lagunas de varzea, llanuras inundables, Bolivia. ABSTRACT The trophic structures of fish communities in tour Varzea lakes of the Ichilo and Chapare Rivers States of Cochabamba and Santa Cruz; 1605'16°43' S and 64°48'64°72'W) were studied during tour hydrologic seasons in 1994 and 1995 by means of stomach content analysis of 1 111 individuals, pertaining to 52 species. The alimentary index was used to group the species in the tour trophic categories of carnivores, herbivores, omnivores, and detritovores. The most diverse groups, in terms of species number; were the omnivores and carnivores. In terms of number of individuals, the carnivores where dominant, representing more than 50% of the total. Omnivores and detritovores were less common with herbivores being least abundant. Temporal and spatial analysis of the trophic structure showed that the differences between lakes were small, while variations between hydrological seasons were more important. This variation resulted in an increase in herbivores during the high-water season. Trophic webs for the lakes were developed. No important variations between lakes or between hydrologic seasons were observed. In sum due to the lesser importance of detritivores, herbivores, and omnivores compared to carnivores and due to a more stable structure with respect to hydrologic changes, the trophic structure of these lakes seems to be different from those described for large Amazon rivers or other similar south American river systems, such as the Orinoco and Parana river systems. Key Words: Trophic structure, trophic webs, fish, Ichilo River Chapare River, Varzea, lakes, floodplain, Bolivia.esHumanitiesarticle