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Macroinvertebrates are important for processing leaf detritus in temperate streams, but studies about their role in tropical streams often present conflicting results. Via digestive tract analyses, we assessed the diets of Phylloicus sp. larvae (Trichoptera: Calamoceratidae), collected from streams of two southeastern Brazil river basins (Araguari, Sao Francisco). We classified gut contents as coarse particulate organic matter (CPOM), fine particulate organic matter (FPOM), algae, animal tissue, vascular plant tissue and mineral material. We hypothesized that the diets of Phylloicus larvae would be related to the physical habitat of the streams (e.g., riparian vegetation, organic matter availability and morphological characteristics), larval size and river basin. Although FPOM content predominated in both basins, we found greater CPOM content in Phylloicus larvae of Upper Sao Francisco sites, and this food item was related to greater riparian vegetation canopy density. The FPOM content was greater in larvae of Upper Araguari sites, and this food item was correlated with greater instream brush cover. Algae, animal tissue, vascular plant tissue and mineral material were very rare in the digestive tracts, and therefore could not be explained. These results indicate the importance of riparian vegetation structure in modulating feeding habitats of macroinvertebrates. We conclude that the Phylloicus larvae had more flexibility in what they eat than we might expect based on their traditional classification as shredders. Therefore, trusting in published classifications, ignoring regional or local differences, may be inaccurate. Instead, regional studies of feeding habits are needed for accurate classifications of invertebrate taxa into trophic guilds.

Studies on aquatic insects have found divergent results when assessing the effects of the environment and spatial structure on the community. The inappropriate choice of taxonomic resolution or variables may be the determinant for such results. We tested whether identification to the family level is enough to approximate results obtained using genus in detecting environmental and spatial effects. We sampled the aquatic insect communities in 110 streams of the Brazilian Cerrado (vegetation type savanna). We used PROTEST analyses to determine the similarity of community configuration at the family and genus resolutions and the overlap of community structure among all pair of insect orders. We used a partial redundancy analysis (pRDA) to determine the effects of environmental and spatial factors, for the entire community and for each insect order individually. The community configurations using family and genus were congruent, as were one-third of orders. The family level reduced the unexplained portion of variance when compared with genus level. Water movement, chemical condition and habitat integrity were relevant for community structure. In addition, the use of family level is a good alternative for studies using aquatic insect communities in Cerrado streams.

No presente trabalho, dados sobre Ephemeroptera e Trichoptera (ET) de um riacho de cerrado foram analisados, com o objetivo de testar a hipotese de que a alta sazonalidade neste bioma pode alterar a composicao de ET entre as estacoes chuvosas e de seca. A estrutura da comunidade foi avaliada utilizando a Analise de Correspondencia Destendenciada e a Analise de Agrupamento (Morisita-Horn, UPGMA). Os fatores ambientais foram submetidos a Analise de Componentes Principais. Para testar a influencia das variaveis abioticas sobre a fauna, foram utilizados o Procrustean Randomization Test (Protest) e o Teste de Mantel. Os fatores ambientais registrados influenciaram significativamente a fauna de ET do Corrego do Pedregulho. A similaridade faunistica foi alta ao longo do ano, indicando que, apesar de a densidade flutuar em resposta a variacao da precipitacao, a composicao faunistica apresentou baixa variabilidade temporal. Por outro lado, foi possivel constatar que o genero Lachlania (Ephemeroptera) ocorreu, preferencialmente, nos meses chuvosos e que a composicao da fauna da estacao seca variou menos do que aquela das demais estacoes. Portanto, a sazonalidade ambiental afetou parcialmente a composicao da fauna de ET do Corrego do Pedregulho. Abstract In this paper, data on the fauna of Ephemeroptera and Trichoptera (ET) from a Cerrado stream was analysed in order to test the hypothesis that the high seasonality of this biome can influence the composition of ET between the wet and dry seasons. The community structure was evaluated using Detrended Correspondence Analysis and Cluster Analysis (Morisita Horn-UPGMA). Environmental factors were analyzed using the Principal Components Analysis. In order to test the effect of abiotic variables on the fauna, It was applied the Procrustean Randomization Test (Protest) and Mantel Test. The environmental factors recorded for this study had a significant effect on the ET fauna from Corrego do Pedregulho. Faunal similarity was high throughout the year, indicating that although there was density of fluctuation, due to rainfall variation, the faunal composition showed little temporal variability. On the other hand, it was possible to observe that the genus Lachlania (Ephemeroptera) occurred preferably during the rainy months and that the faunal composition during the dry season was less variable than those from other seasons. Therefore, environmental seasonality had a partial effect on the faunal composition of ET from Corrego do Pedregulho.

EnglishBIOMONITORING THE WATER QUALITY USING BENTHIC MACRO-INVERTEBRATES: AN ADAPTATION OF BMWP BIOTIC INDEX TO A BRAZILIAN WATERSHED. The water quality of a watershed of Goias state, Brazil was evaluated using benthic macroinvertebrates through an adaptation of the BMWP (Biological Monitoring Working Party Score System) method. This approach was based on correlating water physical and chemical characteristics with the frequency of occurrence of different families of benthic organisms. A water quality rating system was designed by assigning different scores to each found family of benthic macroinvertebrates, being used to identify the degree of ecological alterations caused by anthropogenic infl uence on the basin. Keywords: Biomonitoring, BMWP, Water Quality, Benthic Macroinvertebrates, Meia Ponte river. portuguesFoi realizado o biomonitoramento da qualidade de agua utilizando os macroinvertebrados bentonicos, atraves do uso de uma adaptacao regional da metodologia do BMWP �Biological Monitoring Working Party Score System��, tendo como referencia a Bacia Hidrografi ca do rio Meia Ponte-GO, que relacionou as caracteristicas fisico-quimicas da agua e a frequencia de ocorrencia dos organismos bentonicos em nivel de familia. Considerando os novos �scores�� estabelecidos para as familias de macroinvertebrados bentonicos da referida bacia, foi determinado um Sistema de Classifi cacao da Qualidade da Agua, visando identifi car o grau de alteracao das caracteristicas ecologicas frente as condicoes ambientais dessa bacia. Palavras-chave: Biomonitoramento, BMWP, Qualidade de Agua, Macroinvertebrados Bentonicos, rio Meia Ponte.

This study analyzes the interaction of fish assemblages with 14 physicochemical and hydrogeomorphological variables at 31 sampling stations along the watershed of the Meia Ponte River, Upper Parana Basin, Central Brazil, during low and high water seasons in 2001. This river and its tributaries drain both urban and agricultural areas. Fish were caught with sieves along a 100 m stretch demarcated in every sampling site, where environmental variables were also measured. A total of 3508 individuals belonging to 31 species were collected. Fish abundance and environmental data matrices were submitted to a multivariate analysis of co-inertia. Two axes were retained for interpretation (total variance explained = 63.65%) indicating that pH, water temperature, conductivity, chemical dissolved oxygen, and turbidity, all have an influence on fish assemblage structure. The co-structure found (fish assemblages and physicochemical variables) is correlated in both of the axes considered (r = 0.73 and r = 0.68, respectively), and is statistically significant (Monte Carlo test, P < 0.001). This co-structure is regulated by seasonality, but is influenced by fish habitat preferences, spawning and available food, the extent and effects of anthropogenic activities (domestic sewage, agriculture, ranching, urban areas) and the position of sampling stations along the watershed.

Stream ecology studies see to understand ecological dynamics in lotic systems. The characterization of streams into Functional Process Zones (FPZ) has been currently debated in stream ecology because aquatic communities respond to functional processes of river segments. Therefore, we tested if different functional process zones have different number of genera and trophic structure using the aquatic insect community of Neotropical streams. We also assessed whether using physical and chemical variables may complement the approach of using FPZ to model communities of aquatic insects in Cerrado streams. This study was conducted in 101 streams or rivers from the central region of the state of Goias, Brazil. We grouped the streams into six FPZ associated to size of the river system, presence of riparian forest, and riverbed heterogeneity. We used Bayesian models to compare number of genera and relative frequency of the feeding groups between FPZs. Streams classified in different FPZs had a different number of genera, and the largest and best preserved rivers had an average of four additional genera. Trophic structure exhibited low variability among FPZs, with little difference both in the number of genera and in abundance. Using functional process zones in Cerrado streams yielded good results for Ephemeroptera, Plecoptera, and Trichoptera communities. Thus, species distribution and community structure in the river basin account for functional processes and not necessarily for the position of the community along a longitudinal dimension of the lotic system.

Alpha, beta and gamma are three components of species diversity. Knowing these attributes in floodplain lake phytoplankton communities is vital when selecting conservation areas. Species diversity is commonly used with other taxonomic groups, but rarely with phytoplankton. We compared the number of phytoplankton species (alpha diversity) from 21 Middle Araguaia River floodplain lakes in the 2000 and 2001 rainy and dry seasons. From these samples we estimated complete survey species richness (gamma diversity), quantified differences in species composition between lakes (beta diversity) and assessed the influence of abiotic variables on beta diversity. We recorded a total of 577 taxa. The Sjack1 estimator indicated that 62.31% of taxa were sampled in the 2000 rainy and 67.65% dry seasons, and 68.36% in the 2001 rainy and 73.5% dry seasons. In almost all seasons, alpha diversity negatively correlated with latitude. Beta diversity (β-1) was higher in high water periods, especially in 2000. This may have been caused by isolated heavy rainfall, which would have increased environmental heterogeneity and raised beta diversity. DCA showed differences in phytoplankton composition between rainy and dry seasons in 2000 and 2001, reflecting the influence of flood pulses on phytoplankton composition. The Mantel test indicated spatial distribution patterns where geographically more distant lakes had less-similar phytoplankton communities.

This work analyses the attributes of the phytoplankton community (species richness, biovolume, diversity, equitability, abundance, dominance and size structure) associated with some physical, chemical and climatic variables of floodplain lakes of the Araguaia River, central Brazil, in the rainy and dry seasons of 2000 and 2001. The lakes in 2000 and 2001 presented different limnological characteristics between the periods of high and low water. The phytoplankton comprised 292 taxa, mainly Chlorophyceae and nanoplankton. In the dry seasons of both years, the functional group Y (Cryptophyceae) was the most prominent association. In high-water periods, different functional groups dominated the lakes. The canonical correspondence analysis (CCA) demonstrated a separation between the rainy and dry seasons of both years. The high and low water presented different dynamics in 2 years due to the influence of the flood pulse.

This study evaluates the flows that can be allo- cated to users in the Bois River Basin and its sub-basin, Peixe River Basin, in Goias, in order to provide informa- tion for water resources management instruments estab- lished by Federal Law 9.433/97, emphasizing charging for the use of water resources. The Bois River Basin covers 34,552.04 km 2 , correspond- ing to 10% of the total area of Goias. A large amount of river flow data is available, supplied by twenty stations, with historical series and distribution that allowed the regionalization of the flows at the exit from the basin. The RH 3.0 software was developed by Minas Gerais Rural Foundation - RURALMINAS and Federal University of Vicosa, with the support of the Department of Water Re- sources of the Ministry of the Environment. It was used to estimate the guaranteed flow 95% of the time (Q 95 ) to the outflow from Bois River Basin, obtaining the value of 118.100 l/s. The Goias State Council for Water Resources (CERH- GO), in resolution 09/2005, established Q 95 as reference flow for water use rights under the state domain. The maximum flow that can be allocated corresponds to 70% of Q 95 , or, for the Bois River Basin, 82.670 l/s. To check the feasibility of using this reference flow and the portion allocated, the study performed a survey of the criteria used in eleven Brazilian states. The Peixe River Basin has a drainage area of 287.49 km 2 . In this basin, the complete lack of hydrological data and the impossibility of data transfer because of the small drainage area prevent the calculation of Q 95 and its use as Avaliacao das Vazoes Alocaveis na Bacia Hidrografica do Rio dos Bois e sub-bacia do Rio do Peixe, Estado de Goias 58 reference flow. Such situations are common in most small river basins in Goias. In such cases, according to CERH-GO resolution 09/2005, the smallest flow ever measured, preferably during a drought period using a precision

The stonefly (Pleeoptera) nymphs of streams of the Almas River basin, Pirenópolis, Goiás State, Central Brazil, and some abiotie factors that might affect their temporal distribution were studied. Nymphs were sampled monthly (June 1993 to July 1994) in five stations with a Surber sampler, and each sample consisted of 20 units totalling 2 m². In each station, stream velocity, discharge, temperature, electrical conductivity and pH were measured in order to assess their influence on the density of nymphs. Nymphs were identified to genus level. In general, the annual variation in density of nymphs, in four stations, showed that the seasonal variation was not clearly influenced by the annual rain cycle. In the case of the one of the stations, where numbers of stonefly nymphs were low and the anthropic action high, there was a density peak in the rainy season. This peak was probably related to dilution of the organie pollution in the rainy season, improving the environmental conditions for the Pleeoptera.

O objetivo deste trabalho foi avaliar a estrutura e dinâmica das populações de fitoflagelados nos períodos de chuva e estiagem dos anos de 2000 e 2001 nas lagoas de inundação do rio Araguaia. As análises foram baseadas na riqueza específica, composição florística e biovolume dos fitoflagelados que estão associadas a determinadas variáveis climáticas, físicas e químicas da água. O teste de Mantel evidenciou um fraco padrão espacial das populações de fitoflagelados, além disso, o teste de Mantel corroborou a importância do componente local na estrutura dessas populações. Os escores derivados da DCA, aplicadas aos dados biológicos demonstram que os períodos de águas altas e baixas não se diferenciaram fortemente em 2000 e 2001, entretanto foi possível notar variação interanual das populações de fitoflagelados. Os dados de biovolume indicaram que existiu um fitoplâncton predominado por Chryptophyceae (grupo funcional Y) e Euglenophyceae (grupo funcional W1) em 2000 e 2001. A riqueza especifica e o biovolume responderam ao pulso de inundação, tanto as águas altas como as águas baixas apresentaram dinâmicas distintas nos dois anos o que pode indicar a importância do pulso de inundação sobre os fitoflagelados.

In this paper the spatial distribution of Plecoptera nymphs in the Almas' River basin, Pirenópolis, GO, was studied. Two Surber samples, each comprising 20 sampling units and totalling 2 m², were taken in each of the 13 stations, one during the rainy season (January 1994) and the second during the dry season (July 1994). In 5 of these stations, monthly samplings were made from June 1993 to July 1994; in these, temperature, velocity, discharge, electrical conductivity and pH were measured. Regional rainfall was also obtained. To ascertain the distribution of nymphs in the habitat, a separate sample was taken. Of the factors considered, the most important affecting the spatial distribution of the stonefly nymphs were altitude, stream order, and anthropic influence. Locally, the genera Anacroneuria and Kempnyia showed clumped distributions, but the data for Gripopteryx and Tupiperla were inconclusive due to low numbers.

A survey of the stonefly (Plecoptera) fauna of streams of the Almas River basin, Pirenópolis, Goiás State, Central Brazil, is presented as well as data of some factors that could affeet the temporal distribution of the adults. For checking adult phenology, light sources were used in three stations from June 1993 to Jully 1994. The sampled individuais were identified to species or morphospecies, as possible. In this study, 301 individuais belonging to the perlid genera Anacroneuria Klapálek, 1909, Kempnyia Klapálek, 1916 and Macrogynoplax Enderlein, 1909 were collected. Adults of most species were collected along the studied period, except for those of Kempnyia that were restricted to the warm-rainy season, the same pattern for this genus in southeastern Brazil. Although adults of most species were collected along most of the studied period, the largest number of adults was collected in the months with larger mean temperatures, showing a clear seasonality in abundance.

This study was conducted in the Meia Ponte River basin, which is located in the Cerrado biome. The objective was to describe the structure of fish assemblages and to evaluate the results with the regard to the position of the tributaries (sampling stations) along the basin. This basin drains 35 municipalities of Goiás State. Springs of the Meia Ponte are located in the district of Itauçu (GO), in the Serra dos Brandões. Two sampling were conducted, one in the rainy season (March/2001) and another in the dry season (August/2001). Thirty sampling sites in tributaries and one in the channel of the Meia Ponte River, in its upper course, were selected to capture fish with dipnets (3 mm mesh) during one hour, along 100-m stretch. Sampling periods (season; rainy and dry) and the categorization according to the distance of the sampling station from the mouth of the Meia Ponte River (position; upper, intermediate and lower) were used to evaluate differences in fish assemblage structure, summarized by a detrended correspondence analysis (DCA), applied on the abundance data matrix, squared root transformed, to eliminate the effect of abundant species. The first two axes were retained for interpretation (eigenvalues = 0.35 and 0.24, for axis 1 and 2, respectively). The two-way ANOVA (factors seasons and positions) identified significant differences (p