Macroinvertebrate shredders consume preferably leaves conditioned by fungi and bacteria which offer greater palatability to them. Plant species in Cerrado present high concentration of chemical elements such as lignin and cellulose, phenols and tanins thus making them less attractive for shredders consumption and limiting the palatability. This study aimed to evaluate the feeding preference of a macroinvertebrate shredder of the genus Phylloicus for plant material from two different biomes (Cerrado and Mata Atlântica), after conditioning in a stream of Mata Atlântica and observing their physical and chemical characteristics. Senescent leaves were collected, monthly from the litterfall of riparian vegetation in a 500 m stretch of a stream in each biome from August 2014 to January 201. The most abundant species in each stream was selected for the experiment. The experimental design consisted in with two treatments. The first (T1) comprised leaf discs from Chrysophyllum oliviforme (Cerrado species) together with leaf discs of Miconia chartacea (Atlantic Forest species) which were conditioned in the Atlantic Forest stream. The second treatment (T2) involved leaf discs of Miconia chartacea conditioned in Mata Altlântica and Cerrado streams. Both tests had showed significant differences between the two treatments (T1 and T2). For T1, there was consumption of M. chartacea leaf discs by Phylloicus sp., but there was no consumption of C. oliviforme discs. For T2, there was preference for M. chartaceae leaves conditioned in a stream of Mata Atlântica than in Cerrado stream. The results showed that Phylloicus sp., had presented preference for food detritus of the Mata Antlântica biome and rejection to the one from Cerrado biome.

Generally, aquatic communities reflect the effects of anthropogenic changes such as deforestation or organic pollution. The Cerrado stands among the most threatened ecosystems by human activities in Brazil. In order to evaluate the ecological integrity of the streams in a preserved watershed in the Northern Cerrado biome corresponding to a mosaic of ecosystems in transition to the Amazonia biome in Brazil, biological metrics related to diversity, structure, and sensitivity of aquatic macroinvertebrates were calculated. Sampling included collections along stretches of 200 m of nine streams and measurements of abiotic variables (temperature, electrical conductivity, pH, total dissolved solids, dissolved oxygen, and discharge) and the Index of Habitat Integrity (HII). The values of the abiotic variables and the HII indicated that most of the streams have good ecological integrity, due to high oxygen levels and low concentrations of dissolved solids and electric conductivity. Two streams showed altered HII scores mainly related to small dams for recreational and domestic use, use of Cerrado natural pasture for cattle raising, and spot deforestation in bathing areas. However, this finding is not reflected in the biological metrics that were used. Considering all nine streams, only two showed satisfactory ecological quality (measured by Biological Monitoring Working Party (BMWP), total richness, and EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness), only one of which had a low HII score. These results indicate that punctual measures of abiotic parameters do not reveal the long-term impacts of anthropic activities in these streams, including related fire management of pasture that annually alters the vegetation matrix and may act as a disturbance for the macroinvertebrate communities. Due to this, biomonitoring of low order streams in Cerrado ecosystems of the Northern Central Brazil by different biotic metrics and also physical attributes of the riparian zone such as HII is recommended for the monitoring and control of anthropic impacts on aquatic communities.

Os recursos hídricos são os mais afetados pela atividade agrícolas de uma região, comprometendo as características dos sistemas hídricos. A expansão da fronteira agrícola e o uso de fertilizantes e agrotóxicos, que vem ocorrendo no Cerrado Tocantinense, constitui uma grande ameaça à qualidade, conservação e a biodiversidade desse ambiente, sendo assim necessário um maior controle para a preservação da qualidade das águas. Tendo isso em vista, este trabalho avaliou a diversidade de macroinvertebrados bentônicos e classificou a qualidade ecológica, utilizando índices biológicos, Índice Biótico de Famílias de Hilsenhoff (IBF) e Biological Monitoring Working Party-score (BMWP) baseados na presença e ausência de organismos aquáticos, para avaliação da degradação ambiental e saúde desse ecossistema. Verificou-se que as amostras do período seco apresentaram uma maior diversidade de organismos coletados, embora tenham apresentado uma menor abundância relativa em relação a organismos sensíveis indicadores qualidade ecológica. Segundo os diferentes índices biológicos utilizados o índice IBF foi o que atribuiu menor qualidade ao recurso hídrico. Relacionou-se esta poluição com período amostrado, indicando uma grande poluição por substâncias orgânicas no local de estudo. Os macroinvertebrados utilizados como indicadores de bioavaliação, classificou a água do Rio Formoso com presença de poluição em um longo prazo, mostrando assim um impacto no ecossistema.

The expansion of the agricultural frontier poses a major threat to the quality of water bodies and conservation and biodiversity of biomes. In the Tocantins-Araguaia, hydrographic region is located the largest irrigated flood type rice project in the world, and in the inter-harvest period, the area is still used for soybean production. Considering the great economic, environmental and social importance of the area, the objective of this study was to evaluate the water quality Considering the great economic, environmental and social importance of the area, the objective of this study was to evaluate the water quality of a river in the Amazon Region, Brazil, and to identify the critical pollution sites in the area of influence of the agricultural project. The monitoring occurred between April 2018 and February 2019, during periods of drought and drought. The water quality was evaluated based on the determination of 34 physical-chemical and 2 microbiological parameters. The comparison of the values obtained with the limits allowed by the legislation for class II waters pointed out samples with high total phosphorus values, which can lead to eutrophication phenomena, concentrations above the expected of metals such as Fe, Cu, and Mn and samples with low percentage of dissolved oxygen. The main component analysis (PCA) showed little variation along the river, i.e., homogeneity in the different points evaluated in the same collection; however, the comparison between collections with different seasonalities revealed quite divergent results, reinforcing that seasonal variations can aggravate the changes in the water quality of the river.