Variação espaço-temporal dos macroinvertebrados bentônicos e nectônicos no reservatório do rio Verde, Paraná, Brasil

Abstract

Water is essential to the ecological balance and maintenance of life, however disturbances of different magnitudes have seriously affects their quality. In this sense, various analysis methodologies seek to measure the rate of contamination using evaluation of physical, chemical and biological parameters. Reservoirs can be classified as semi-lotic ecosystems originated from the damming of rivers and the distribution of organisms in this water body is influenced by physical, chemical and biological/ecological interactions. The Verde river reservoir is located on the borderland of the cities of Campo Largo and Araucaria, Parana State. The present study aimed the physical and chemical characterization of water and sediment, as well the evaluation of aquatic and benthic macroinvertebrates in four sample points along four seasons in the reservoir between the years 2013 and 2014. Relative to the physical and chemical parameters, all except organic matter are within the recommended values for relevant legislation. The macrofauna of the reservoir proved to be rich and diverse. A total of 1880 organisms were collected, with only 938 in the sediment. Over the sample period was recorded the presence of bioindicators taxa as well organisms of medical and ecological importance. According to the multiple linear regression model, the significant factors for the distribution of the benthic community were pH, water temperature, dissolved oxygen, dissolved oxygen saturation, conductivity, suspended matter (total, organic and inorganic), turbidity, chlorophyll- a, nitrite, nitrate, organic matter, humidity, phosphorus and total nitrogen and grain size medium sand fractions, fine sand and silt/clay. For the composition of trophic guilds, were registered five groups: collectors, predators, scrapers, slicers, filterers and shredders. From the non-parametric linear regression test, were considered significant the variables turbidity, depth and granulometric fractions. The result of the quality index BMWP ' and Shannon -Wiener Diversity suggests moderate pollution, a result that complements that obtained exclusively by physical and chemical analysis, corroborating the importance of including the assessment of aquatic and benthic communities in environmental monitoring programs.