The influence of sand extraction on fish assemblages in campinarana streams in Cruzeiro do Sul – AC, Brazil

Abstract

Habitat destruction promoted by sand extraction from streambeds can cause the loss of some species and change the dynamics of fish assemblages. The present study investigated the effect of sand extraction on fish assemblages in campinarana streams in the region of Cruzeiro do Sul, Acre, between June 2017 and August 2018. Six streams were evaluated, including three degraded by sand extraction and three in forested areas. Richness, a Shannon diversity index, equitability and abundance of species were evaluated. To verify differences between these parameters, a Student’s t-test was conducted. NMDS and PERMANOVA were summarized to evaluate the composition of fish species. We collected 705 individuals distributed in 60 fish species. We found a significant difference between the areas regarding richness (t = 11.1, p = 0.0001), abundance (t = 4.5, p = 0.006) and diversity (t = 4.1, p = 0.01). The species composition also varied (Pseudo-F = 3.79, P = 0.01), since 35% of the species were restricted to preserved environments. Thus, it is suggested that the anthropic disturbance in the campinaranas caused the loss of the most sensitive and specialized species, which caused an increase in opportunistic individuals, altering the structure of the assemblages and reducing local diversity.

Keywords

• Anthropization
• Diversity
• Fish composition
• Ichthyofauna
• Riparian vegetation