Abstract
Feeding ecology is an integrative procedure to highlight different diets, associating feeding trends with governing and regulation factors characterizing foraging species and their environments, respectively. The diet variability of seven fish species forming a community in a Neotropical riverine system was analyzed to characterize the resource and consumer linkages, providing a detailed assessment of adaptive feeding behaviors of fishes living in different ecological states transiting from natural/resilient spaces to anthropic pressions-linked disturbed ones. Fishes were sampled along four sites during a year, and their stomach contents were analyzed. Feeding data were analyzed by applying quali- and quantitative methods with multi-levels and multifactor aspects to determine target food categories (percentage of occurrence) and identify feeding patterns (correspondence and cluster analyses, CA-HCA). Factors and scales governing target food categories were also tested. A total of 483 stomachs were dissected, and 30 food categories were identified. CA-HCA highlighted 10 feeding trends (FTs) combining several foods co-occurring at distinct levels. These FTs indicated characteristic diets and high diversity of feeding behaviors concerning multiple and narrow diets, different alimentary needs related to ecomorphological features, different plasticity ranges (adaptability, tolerance) and a spatial governing effect (headwater to river mouth environmental quality loss). These multiple factors provided essential information on overcoming ways of environmental constraints and optimization ways of food balances helping to better manage the richness and working of neotropical river systems.