Ictiofauna de baías do Pantanal com histórico de fogo no Pantanal, Mato Grosso do Sul

Abstract

The Pantanal is one of the largest floodplains on the planet. One of the factors What favors flooding is its low slope, with slow water drainage. The flood pulses shape the landscape of the plain and are responsible for the formations of intermittent or permanent marginal bays along the course of the river Paraguay and its tributaries. With the increase in fire outbreaks in the biome, local characteristics are modified, as the residues from these fires change water conditions, directly and indirectly influencing communities aquatic. Therefore, the general objective of this work was to evaluate the fish community of bays on the Paraguay River, located in the municipality of Corumbá, MS, with different fire historical. The fish were collected over a year, in eight marginal bays divided into two treatments: four high fire frequency bays and four low fire frequency bays. In total four collections were carried out, one in each hydrological period (ebb, drought, inundation e flood). PcoA, RDA and GLM analyzes were made for fish diversity, habitat condition and water quality, as well as functional diversity analyses. It was observed that the permanent bays did not have species changes in the community. During the inundation and floods, due to connectivity with the river, there was a greater flow of species in the intermittent bays. In the multivariate analyzes it was possible to verify that each bay presented a dynamic individual related to the characteristics of the environment and the diversity of fish; the variables that most negatively affected communities were the percentage of vegetation inside the bays and the concentration of dissolved oxygen, while the variable that most benefited was the turbidity of the water. In this way, the fish communities of the Paraguay River in the Pantanal bays are more influenced by flood pulses and the individual characteristics of each bay (e.g., vegetation, bay size and distance from river channel), than by the history of fire frequency.