Estrátegia reprodutiva de peixes de um rio impactado por empreendimento hidroelétrico na Amazônia Central

Abstract

According to many concepts, habitat is the model from which life history traits evolve. Moreover, organisms may exhibit different responses to natural or anthropogenic environmental changes by modifying their morphological, physiological or behavioral characteristics, which are possible if the species presents a degree of phenotypic plasticity high enough to allow adaptations to the environmental changes. This work aimed to investigate the effects of the impoundment occurred in the Uatumã River, as consequence of the construction of the UHE Balbina, on the reproductive life history strategies of its ichthyofauna. Therefore, (1) the life history traits of species were describe, (2) according to these traits, the species were clustered into reproductive strategies according to the “triangular continuum” model proposed by Winemiller (1989), and (3) it was identified how these traits varied under different situations (before and after the impoundment) and between different areas (reservoir and downstream river) after impoundment. Surveys were carried out bimonthly, up and downstream, for both pre-impoundment (1985) and post-impoundment (2005 to 2007) phases. The results for the post impoundment phase indicate a higher proportion of fishes with seasonal strategy occurring in the river area, while in the reservoir there was a higher proportion of equilibrium and opportunistic strategies. The changes observed in the life history traits 20 years after the construction of the dam highlight their plasticity, a mechanism used by the organisms for their maintenance and colonization of this newly formed environment.