Ocorrência de macroinvertebrados bentônicos em ecossistema aquático localizado em área agrícola no município de Campo Verde-MT

Abstract

Agriculture is considered the main responsible for disturbances in water ecosystems. As a result of the expansion of agricultural activity was the removal of vegetation in many areas and the degradation of the physical and chemical structure of the sediment, causing imbalance to the existing community there. The benthic macroinvertebrates are among the main organisms used in the evaluation of environmental and biological monitoring in aquatic ecosystems. The distribution of these organisms is mainly determined by the type and diversity of habitats available to the community. As a result, this paper aims to contribute to the database on the distribution of macroinvertebrates in the state of Mato Grosso, as well as understanding the effects of agricultural crops in the benthic macroinvertebrate communities in a dam in the agricultural area in the municipality of Campo Verde, State of Mato Grosso. The study area is located in the headwaters of the São Lourenço River - TM, the sample collection site is located on Farm Pirassununga, Campo Verde, Mato Grosso, where soybeans are grown, millet and cotton (latitude S 15 ° 37 '18.8 "W and longitude 55 o 10 '24.8"). In its vicinity (ca. 30 m) was dammed one of its sources, sampled at its input (P2) in the limnetic zone (P3) and its output (P4). In addition to these three points, we sampled one of their sources (P1) and a stream below the dam (P6). Each point was sampled six times, three during the rainy season and three during the dry season, with three replicates at each point. For sediment was collected using a Petersen dredge an area of 0.0375 m2

for sample collection of invertebrates, particle size analysis and organic matter. We made the following physical and chemical analysis of water as an aid to interpretation of the macroinvertebrate community: temperature water, pH, electrical conductivity, turbidity, color and dissolved oxygen. The results showed that the prevalence of organisms occurred in the rainy season, with 216 agencies in the sampling points P2 and P3, characterized by means of input and dam, respectively. The order Diptera was more abundant during the rainy season, represented by the family Chironomidae. The results were influenced by the amount of rainfall recorded at the site during the study period, the amount of organic matter in sediment and recorded mainly by the characteristics of the site, where the absence of riparian vegetation and human activities in the region were crucial for the results.