Fish assemblage structure and aquatic pollution in a Brazilian stream: some limitations of diversity indices and models for environmental impact studies
S. E. Lima-Junior1, I. B. Cardone2, R. Goitein2
1Laboratório de Análise e Monitoramento Ambiental do Gás Natural, Universidade Estadual de Mato Grosso do Sul, Dourados, Brazil,
2Universidade Estadual Paulista, Departamento de Zoologia, Rio Claro, Brazil
Ecology of Freshwater Fish, 2006: 15: 284–290.
Abstract
The aim of this study was to describe and quantify the effect of aquatic pollution on the fish assemblage structure of the Corumbataí River (Brazil), by comparing two sites with different water quality characteristics. The results revealed that abundance of individuals was low at the polluted site (B). However, the two sites did not differ significantly in species richness (total and average). This fact contradicts theories stating that portions where the transverse area of the channel is larger should present a higher biological richness. It was also observed that the ichthyofauna of site B had higher evenness, and, consequently, a tendency to a higher diversity than that at site A. This demonstrates that diversity estimates should be used cautiously in environmental impact studies, as they do not necessarily indicate better conditions of communities living in more preserved environments.
Key words: Brazil; Corumbataí River; diversity indices; richness; species abundance models |
