O efeito dos gradientes ambientais em assembleias de peixes de igarapés da BR-319, sudoeste da Amazônia.

Abstract

In addition to being the world’s largest drainage basin, with up to 6.7 million km2, the Amazon watershed is also considered the world’s largest fresh surface water compartment, sheltering around one-third of all neotropical region ichthyofauna biodiversity. The Purus-Madeira basin has an area of around 300,000.000 km2 and is limited, parallelly, by the rivers Purus (on the left) and Madeira (on the right). Starting in Bolivia, and extending to Brazil through the states of Acre, Rondônia, and Amazonas, its surroundings' main access is made by the Alvaro Maia’s Highway, also known as BR-319, which connects Manaus/AM to Porto-Velho/RO. This region holds hundreds of small streams and headwaters systems that can suffer influences occasioned by the occupational processes enabled by the BR-319. Considering the occupational processes' potential to change the ecosystem’s biotic and abiotic variables, whether by reducing species richness or water quality, research is needed to understand the current aquatic fauna species distribution and its water characteristics. In this light, this dissertation's first chapter brings species distribution data of fish captured in third-order streams crossed by the BR-319, and an updated list of the region’s ichthyological fauna. In the second chapter, we seek to understand the effects of environmental variables on the composition and abundance of these species and discuss how the BR-319 could be influencing these dynamics.