Variation in the diet of a small characin according to the riparian zone coverage in an Atlantic Forest stream, northeastern Brazil

Abstract

AIM: in this study we present data from the diet of Astyanax vermilion which were used as a tool to compare two sites of streams with different vegetation cover in Ribeirão Limoeiro, Cachoeira River Basin, BA. METHODS: Four samples were taken (March, June, September and December) using electrofishing as the collection method in two contiguous sites of the headwaters: stretch without riparian vegetation and with riparian vegetation. RESULTS: The qualitative composition of the diet was analyzed by the method of frequency of occurrence. The allochthonous resources of vegetal origin made up the bulk of the diet in the stretch without riparian vegetation with a frequency of occurrence of 64%. In the section with riparian vegetation allochthonous resources of animal origin made up the bulk of the diet with a frequency of 62%, which emphasizes the importance of food items from the surrounding environment. The mean Shannon diversity index, calculated from the frequency of occurrence of food items was significantly different (p = 0.04) when comparing reach deforested (H'= 1.44) with reach forested (H'= 1.80). The average weight of stomachs in the deforested reach (WS D = 0.18g) was significantly higher than that of the forested reach (WS F = 0.14g). CONCLUSIONS: in the stretch with riparian vegetation, the food diversity was greater and the fish that are in the riparian stretch do not need as much food to satisfy their physiological needs. These results underscore the importance of the type of riparian vegetation as a food source for fish

Spatial factors overcome seasonality regulating the consumption of allochthonous food resources by fishes from tropical lotic ecosystems

“…We also show the betweenstudy variance (BSV), the residual heterogeneity (Q E ) and model heterogeneity (Q M ). impacts reduce the input of terrestrial food resources into the water, drastically affecting diet composition food-web structure (Costa et al, 2020;Trindade et al, 2013).…”

“…Microhabitat composition is usually more diverse in tropical streams than temperate regions, which ultimately determines resource use by fish (Soares et al., 2017). Also, differences in land use (e.g., urbanisation and pasture) may have diminished or hidden potential correlates between the consumption of allochthonous food resources by fishes and the predictions of the RCC because these human impacts reduce the input of terrestrial food resources into the water, drastically affecting diet composition and food‐web structure (Costa et al., 2020; Trindade et al., 2013).…”

Ficha de Astyanax vermilion

“…A composição da dieta desta espécie muda quando as áreas com e sem vegetação circundante são comparados, indicando que a espécie exibe um comportamento oportunista. Em estudo de dieta de A. vermilion os recursos alóctones de origem vegetal compuseram a maior parte da dieta no trecho sem mata ripária, com 64 % em frequência de ocorrência; no trecho com mata ciliar, os recursos alóctones de origem animal compuseram a maior parte da dieta, com 62 % de ocorrência, o que ressalta a importância do alimento proveniente do ambiente no entorno (Trindade et al, 2013).…”

Food Resource Sharing Among Benthic and Nektonic Stream Fish Species

“…2/6 2016) and where the forest cover has an important role in the food ecology of stream fish species (Trindade et al, 2013). When riparian vegetation or channel morphology changes, the water biota is affected by the transportation of sediments, increased temperature, breaches of trophic chains, and decreased diversity of habitats (Braga and Gomiero, 2009;Dala-Corte et al, 2017).…”