Metodologias de classificação de peixes em guildas tróficas para uso em estudos ecológicos e avaliações ambientais.

Abstract

Compare the methodologies used in the classification of fish species into trophic guilds and evaluate their influence on the relative abundance and richness of species within guilds formed. Methodologies commonly used in studies of trophic ecology in fish assemblages were selected in South American literature, and it was applied to a data set from the diet of fishes from a Neotropical floodplain. The species were also classified considering its feeding habits (information obtained in literature) and the resulting guilds were classified as "conservative guilds." The results showed differences in the classification of species, according to the methodology applied, being that the visual analysis with the critical point ≥ 70% was the one which best represented the diet of the species. All the evaluated methods included species into guilds that did not represent the main food category consumed, and the methodologies based on multivariate analysis and the critical point ≥ 40%, were less accurate in classifying species according to preferred trophic category. The relative abundance and richness of species of the trophic guilds were influenced by the applied methodology classification. Based on these results, two approaches are suggested for the use of trophic guild in ecological studies and environmental assessments: (i) the feeding habits of the species is used in its classification and guilds are called "conservative guilds; (ii) the diet is used as the foundation of the classification, and the guilds are called "punctual guilds".