Avaliação do impacto da utilização de manilhas na construção de estradas sobre ambientes aquáticos e na ictiofauna em duas rodovias na região sul de Minas Gerais

Abstract

Few studies of the impacts caused by road construction in aquatic environments have been conducted in Brazil. The main reason is that there is no economic interest in the fish fauna of the headwaters. This study aimed to assess these impacts comparing ten streams intercepted by road using culverts, and six streams without them (controls). Each stream was sampled in their dry and rainy seasons along a total stretch of 300 meters, 150 meters downstream and 150 meters upstream of culvert, divided into 20 sections. When comparing data of the physical environment between the two groups, only the presence of wood in the river bed was significantly different between the upstream and downstream regions. The height of the obstacle represented by the culvert, could not explain differences in abundance and fish richness between the two reagionss. However, the similarity analysis indicated that the differences between upstream and downstream communities are related to the culvert height. Overall the results show that the culvert has an impact on the fish fauna and on the physical environment, mainly due to the barrier they represent on the transport of sediment and for fish.