Macro-scale (biomes) differences in neotropical stream processes and community structure

The definition of conservation strategies and ecological assessment schemes requires understanding ecosystem patterns over multiple spatial scales. This study aimed to determine if macro-scale structural and functional (processes) patterns associated with stream ecosystems differed among three neotropical biomes (Cerrado, Amazon, Atlantic Forest). We compared the aquatic communities (benthic invertebrates and hyphomycetes) and processes (decomposition rates, primary production and biofilms growth and aquatic hyphomycetes reproduction rates-sporulation) of Cerrado stream sites (neotropical savannah) against those of stream sites in the connecting biomes of the Atlantic Forest and Amazon (rainforests). We expected that, contrary to the biome dependency hypothesis the community structure and processes rates of streams at the biome-scale would not differ significantly, because those ecosystems are strongly influenced by their dense riparian forests, which have a transitional character among the three biomes. Fifty-three stream sites were selected covering a wide range of geographic locations (Table 1), from near the Equator (2° S) in the Amazon, to intermediate latitudes in the Cerrado (12-19° S), and latitudes closer to the tropic of Capricorn in the Atlantic Forest (19º-25° S). We found that: 1) at the abiotic level, the aquatic ecosystems of the three biomes differed, which was mostly explained by large-scale factors such as temperature, precipitation and altitude; 2) functional and structural variables did not behave similarly among biomes: decomposition and sporulation rates showed larger differences among biomes than invertebrate and aquatic hyphomycete assemblages structure; 3) invertebrate assemblages structure differed between the rainforests and Cerrado but not between rainforests (Amazon and Atlantic Forest) whereas aquatic hyphomycetes were similar among all biomes; 4) biofilm growth and algae concentration in biofilms of artificial substrates were highly variable within biomes and not significantly different between biomes. Overall, aquatic ecosystem processes and community structure differed across biomes, being influenced by climatic variables, but the variation is not as pronounced as that described for terrestrial systems. Considering the potential use of these functional and structural indicators in national-wide ecological assessments, our results indicate the need to define different reference values for different biomes, depending on the variable used. The approach followed in this study allowed an integrative analysis and comparison of the stream ecosystems across three tropical biomes, being the first study of this kind. Future studies should try to confirm the patterns evidenced here with more sites from other areas of the three biomes, and especially from the Amazon, which was the least represented biome in our investigation. © 201

Plant litter dynamics in the forest-stream interface: Precipitation is a major control across tropical biomes

Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even though the tropics occupy 40% of the Earth's land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Amazon forest and Cerrado savanna), predicting major differences among biomes in relation to temperature and precipitation regimes. Precipitation explained most of litter inputs and storage, which were generally higher in more humid biomes (litterfall: 384, 422 and 308 g m-2 y-1, storage: 55, 113 and 38 g m-2, on average in Atlantic forest, Amazon and Cerrado, respectively). Temporal dynamics varied across biomes in relation to precipitation and temperature, with uniform litter inputs but seasonal storage in Atlantic forest streams, seasonal inputs in Amazon and Cerrado streams, and aseasonal storage in Amazon streams. Our findings suggest that litter dynamics vary greatly within the tropics, but point to the major role of precipitation, which contrasts with the main influence of temperature in temperate areas. © 2017 The Author(s)

Educação para a saúde junto a um grupo de adolescentes: relato de uma experiência de estudantes de enfermagem

Trata-se da abordagem sobre a elaboração de um programa de Educação em Saúde, para um grupo de adolescentes. Tomou-se como base o referencial teórico sobre pesquisa-ação para se definir os procedimentos do trabalho. Para tanto, vêm-se desenvolvendo reuniões semanais com o grupo de adolescentes, nas quais a participação destes tem demonstrado que o medo, a vergonha, a insegurança, decorrentes da desinformação sobre saúde e a privação de contatos reais com a pessoa do outro, se constituem em importantes indicadores que dificultam o viver sadio dos adolescentes

Variação espacial da comunidade bêntica no reservatório de Corumbá, Estado de Goiás, Brasil - DOI: 10.4025/actascibiolsci.v25i1.2078

The benthic community composition and abundance were analyzed in three stations of the Corumbá reservoir. Collections were undertaken at the margin and the center of the stations, aiming to analyze the abiotic parameters affecting this community. Variables such as depth, dissolved oxygen and sediment type were the main factors that determined the benthic community structure. Fauna was abundant in the marginal region, probably because of the lower depth and higher dissolved oxygen concentrations. The opposite occurred at the central region, with the exception of the reservoir's riverine station. This fact may be due to the shallowness of the place and the water current high speed. Oligochaeta and Chironomidae were the most frequent and abundant taxa in the Corumbá Reservoir. These results show that the benthic community in the reservoir is spatially related to depth and to dissolved oxygenA composição e a abundância da comunidade bêntica foi analisada em três estações do reservatório de Corumbá. Foram feitas coletas na margem e no centro das estações, visando a analisar os parâmetros abióticos que influenciaram essa comunidade. Variáveis, tais como profundidade, oxigênio dissolvido e o tipo de sedimento, foram os principais fatores que determinaram a estrutura da comunidade bêntica. A fauna apresentou uma maior abundância na região marginal, provavelmente devido às menores profundidades e maiores concentrações de oxigênio dissolvido. O inverso foi verificado na região central, exceto na estação fluvial do reservatório, pois trata-se de um local raso e com maior velocidade de correnteza. Oligochaeta e Chironomidae foram os principais táxons em freqüência e abundância no reservatório de Corumbá. A partir desses resultados, pode-se sugerir que a comunidade bêntica no reservatório estudado está relacionada, espacialmente, com a profundidade e com o oxigênio dissolvid

Benthic macroinvertebrate community structure in a stream of the north-west region of Paran\ue1 State, Brazil

This study aimed to survey the benthic macroinvertebrate fauna of a first order stream located in an agricultural area, and to assess the environmental factors involved in the spatial distribution of this community. Invertebrates were gathered in November 2007 at three sampling sites distributed along the Itiz Stream, located in Marialva municipality, Paraná State. At each site, we measured the physical and chemical variables of the water, and then took four samples, using Surber sampler. In order to evaluate the differences in density, richness, diversity and evenness, we employed an ANOVA and a DCA to summarize biotic data. The invertebrates were categorized into functional groups and the BMWP score was applied to calculate the biological integrity of the environment. The faunal composition was represented by 103 taxa distributed across five phyla, of which the highest occurrence was of arthropods, especially insects. Higher density values were observed for Chironomidae, Ephemeroptera, Coleoptera and Trichoptera. The richness, diversity and density, as well as the density of gathering-collectors, were higher in the intermediate course of the stream. The distribution pattern of the taxa was mainly influenced by lentic or lotic characteristics of the sampled sites and microhabitats, as evidenced by the DCA. The BMWP indices indicated that the three sampling sites presented scores of excellent and good water quality. In the Itiz Stream, the presence of preserved marginal vegetation and the distance from urban centers that generate pollution, combined with peculiarities of each sampling site, influenced the structure of the benthic community

Effect of trophic status and sediment particle size on diversity and abundance of aquatic Oligochaeta (Annelida) in neotropical reservoirs

The influence of the sediment grain size and the trophic status of the reservoirs on the composition, richness and biomass of Oligochaeta community was tested. Samples were taken from the littoral and profundal zones of 30 neotropical reservoirs from six different watersheds during two hydrological periods (dry and rainy seasons). The sample units were ordinated, with principal component analyses, according to differences in the sediment grain size, sample depth and dissolved oxygen. The results of a multiple response permutation procedure (MRPP) analysis revealed significant differences in species composition between littoral and profundal zones, trophic status (oligotrophic, mesotrophic and eutrophic) and different watersheds. The environment–species relationship was tested using redundancy analyses. In order to test which environmental variables, either granulometric or limnological, influenced the Oligochaeta community variability we used a partitioning procedure of inertia. Local variations, including reservoir zone and trophic status, were primarily influenced by differences in sediment type and depth. Significant differences in the total biomass between zones, trophic status, watershed and hydrological period were also demonstrated by a Kruskal–Wallis or Mann–Whitney test. The most prevalent taxa were the cosmopolitan tubificids Bothrioneurum sp. and Branchiura sowerbyi, and the naidids Dero (Dero) digitata and Pristina breviseta, which are dependent on periphyton for food. Higher biomass values were recorded in mesotrophic reservoirs, due to increased nutrient availability and adequate dissolved oxygen supply. Our results indicate that the Oligochaete community structure is directly influenced by local environmental variation in neotropical reservoirs; and that the sediment grain size is the most important factor in determining the Oligochaete community structure

Effect of habitat heterogeneity in the composition and distribution of Chironomidae (Diptera) assemblage in different microhabitats of preserved streams in the Brazilian Atlantic Forest

AIM: This study aimed at to evaluate the influence of habitat heterogeneity on the attributes of richness, abundance, diversity and equitability of Chironomidae assemblage and also the biological differences in faunistic composition related to each microhabitat. METHODS: The sampling was performed in summer (February) and winter (August) 2010, with Surber sampler, in three headwaters streams at Atlantic Forest, in southern Brazil. RESULTS: In the total 6,429 Chironomidae larvae were identified and classified into 96 taxa belonging to Chironominae, Tanypodinae and Ortocladiinae subfamilies. Among the microhabitats, the highest richness was observed in the deposits of litter, and the highest number of exclusive species took place in the pool regions. CONCLUSIONS: Thus, the composition and structure of the Chironomidae assemblage are directly related to the availability and heterogeneity of habitats in streams