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Resumo Simulações climáticas para o clima presente (1960-2005) utilizando o Modelo Climático Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB), forçado com o Brazilian Earth System Model Ocean-Atmosphere (BESM-AO 2.5) foram realizadas. O objetivo deste trabalho é avaliar o desempenho do Modelo Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB) na representação dos componentes do balanço de água (precipitação, evapotranspiração, convergência de umidade, vazão, cota e área de inundação) sobre a bacia do rio Madeira. A característica de sumidouro de umidade (P > E) foi simulada pelo modelo regional. Entretanto, o modelo subestimou a precipitação (33%), a evapotranspiração (12%) e a convergência de umidade (6%). O MGB-IPH conseguiu representar o ciclo anual das vazões, níveis do rio (cota) e área de inundação. Também conseguiu reproduzir a translação e amplitude das ondas de cheia, e o atraso de 3 meses entre os máximos da área de inundação e a precipitação sobre a bacia do Madeira. O MGB-IPH mostrou-se uma ferramenta útil para estudos de variabilidade climática, mudanças no clima e no uso da terra, e também para sistemas operacionais de previsão hidrológica na bacia Amazônica. Abstract Downscaling climate simulation for present climate (1960-2005) based on the Eta Regional Climate Model and MGB Large-scale Hydrological Model, forced by Brazilian Model of the Terrestrial System (BESM-AO 2.5), was carried out. The objective of this work is assessment the performance of the Eta regional model and MGB-IPH in the representation of the components of the water budget in Madeira River basin. The moisture sink characteristic (P> E) was simulated by the regional model. In the terrestrial branch, the MGB-IPH hydrological model was able to represent the annual cycle of discharge, water level and floodplain inundation. The performance of the hydrological model and the regional model was satisfactory in the simulation of the seasonal dynamics of hydrological processes and water budget in Madeira river basin, indicating that the hydrological model is a useful tool for studies of climatic variability, changes in climate and land use and for hydrological forecasting operational systems in the Amazon basin.

High rates of deforestation, either in the past or the present, affect many of the ecological processes in streams. Integrating deforestation history and the current landscape structure enhances the evaluation of ecological effects of land-use change. This is especially true when contemporary landscape conditions are similar but the temporal path to those conditions differs. One approach that has shown promise for evaluating biodiversity responses over time and space is the β-diversity partitioning, which combines taxonomic and functional trait-based approaches. We tested hypotheses related to stream fish assemblages’ turnover in watersheds with different environmental conditions and deforestation histories. We sampled fish from 75 watersheds in the Machado River basin, Brazil, and environmental factors were quantified at multiple scales. Taxonomic turnover was higher than expected by chance, whereas functional turnover was lower than expected by the observed taxonomic turnover, indicating that deterministic processes are structuring these assemblages. The turnover, and the environmental factors differed among watersheds with different deforestation histories. Besides being scale-dependent, turnover patterns are also likely dependent on land use dynamics and involve time-lags. Resumo Altas taxas de desmatamento, seja no passado ou no presente, afetam muitos processos ecológicos em riachos. Integrar o histórico do desmatamento à estrutura atual da paisagem melhora a avaliação dos efeitos ecológicos da mudança do uso do solo. Isto é especialmente verdadeiro quando as condições da paisagem contemporânea são semelhantes, mas seguiram trajetórias distintas. Uma abordagem promissora para avaliar as respostas da biodiversidade ao longo do tempo e espaço é a partição da diversidade-β, que combina abordagens taxonômica e funcional. Testamos hipóteses relacionadas à substituição das assembleias de peixes de riachos em microbacias com diferentes condições ambientais e histórias de desmatamento. Amostramos 75 microbacias na bacia do rio Machado, fatores ambientais foram quantificados em múltiplas escalas. A substituição taxonômica foi maior do que esperada pelo acaso, enquanto a substituição funcional foi menor do que o esperado pela substituição taxonômica, indicando que as assembleias são estruturadas por processos determinísticos. As substituições e fatores ambientais diferiram entre microbacias com históricos de desmatamento distintos. Além de serem escala-dependentes, os padrões de substituição provavelmente são dependentes da dinâmica do uso do solo, envolvendo defasagem temporal.

This study presents an inventory of the ichthyofauna of the lower Roosevelt River sub-basin and its associated tributaries. Fish sampling with fishing nets and measurements of environmental parameters of water occurred in November/2012 (rising water), February/2013 (flooding), May/2013 (falling water) and August/2013 (drought). Depth mean was 8.86 m, water transparency was 0.6 m, conductivity was 22.7 µS.cm-1, pH was 6.59, dissolved oxygen was 7.63 mg.l-1 and temperature was 28°C. The total estimated capture area was 68,829.6 m2 during 2,880 hours. The catch per unit Effort (CPUE) was 0.37 individuals m-2.day-1. Species were spatially aggregated in all sampling points and river water levels. A total of 5,183 individuals distributed in 7 orders, 29 families, 104 genders and 188 species were sampled in this survey. The diversity index was 4.121 and equitability index was 0.789. The Characiforms order was the most abundant with 106 species, followed by Siluriforms with 63 species and Cichliforms with 23 species. The most abundant species was Serrasalmus rhombeus (Linnaeus, 1766) with 327 individuals (5.9%), followed by Chalceus epakros (Cope, 1870) with 309 individuals (5.6%) and Acestrorhynchus microlepis (Schomburgk, 1841) with 250 individuals (4.5%). Trophicity was characterized by omnivorous (28.6%), piscivorous (14.3%), carnivorous (13.8%) and detritivorous (12.8%). According to IBAMA's regulation, 29.25% of captured species presents ornamental potential. Resumo: Este estudo apresenta um inventário da ictiofauna da sub-bacia do baixo Rio Roosevelt e seus tributários associados. As coletas de peixes com malhadeiras e as medições de parâmetros ambientais da água ocorreram em Novembro/2012 (enchente), Fevereiro/2013 (cheia), Maio/2013 (vazante) e Agosto/2013 (seca). A média da profundidade foi 8,86 m, da transparência da água foi 0,6 m, da condutividade foi 22,7 µS.cm-1, do pH foi 6,59, do oxigênio dissolvido foi 7,63 mg.l-1 e da temperatura da água foi 28°C. A área total de captura estimada foi 68.829,6 m2 durante 2880 horas. A captura por unidade de esforço (CPUE) foi 0,37 indivíduos m-2.dia-1. As espécies foram espacialmente agregadas em todos os pontos de coleta e períodos de coleta. Um total de 5183 peixes em 7 ordens, 29 famílias, 104 gêneros e 188 espécies foram coletados. O índice de diversidade foi 4,121 e o índice de equidade foi 0,789. As ordens Characiforme, Siluriforme e Cichliforme foram as mais abundantes. As espécies Serrasalmus rhombeus Linnaeus 1766 com 327 indivíduos (5,9%), Chalceus epakros (Cope 1870) com 309 indivíduos (5,6%) e Acestrorhynchus microlepis Schomburgk 1841 com 250 indivíduos (4,5%) foram as mais abundantes. Os onívoros (28,6%), piscívoros (14,3%), carnívoros (13,8%) e detritívoros (12,8%) foram os indivíduos mais abundantes. De acordo com o IBAMA, 29,25% das espécies capturadas tem potencial ornamental.

The Amazon region, in South America, contains the largest rainforest and biodiversity in the world, and plays an important role in the regional and global hydrological cycle. In the present study, we identified the main sources of moisture of two subbasins of the Amazon River Basin, the Negro and Madeira River Basins respectively. The source-sink relationships of atmospheric moisture are investigated. The analysis is performed for the period from 1980&ndash, 2016. The results confirm two main oceanic moisture sources for both basins, i.e., oceanic regions in the Tropical North and South Atlantic oceans. On the continents are, the Negro River Basin itself, and nearby regions to the northeast. For the Madeira River Basin, the most important continental sources are itself, and surrounding regions of the South American continent. Forward-trajectory analysis of air masses over the source regions is used to compute the moisture contribution to precipitation over basins. Oceanic (continental) sources play the most important role in the Negro River Basin (Madeira River Basin). The moisture contribution from the Tropical North Atlantic region modulates the onset and demise of the rainy season in the Negro River Basin, while the moisture contribution from the rest of the Amazon River Basin, the Madeira Basin itself, and Tropical South America leads to the onset of the rainy season in the Madeira River Basin. These regions also played the most important role in decreasing the moisture supply during most severe dry episodes in both basins. During &lsquo, &rsquo, El Ni&ntilde, o&rsquo, generally occurs a reduction (increase) of the moisture contribution to the Negro River Basin (Madeira River Basin, mainly from April to August) from almost all the sources, causing a decrease in the precipitation. Generally, the contrary occurs during &lsquo, La Ni&ntilde, a&rsquo

The implementation of hydropower projects is one of the greatest threats to fish diversity worldwide, especially in tropical rivers, where many high commercial value species migrate hundreds of kilometers in response to flood pulses. The interruption of river connectivity, caused by the electric impoundments, compromises the connection among habitats that are indispensable for the life cycle of these species, and may negatively affect both their reproduction and recruitment. In this context, the Amazon basin, which contains the largest freshwater fish diversity on the planet, is being heavily threatened due to the increasing construction of hydroelectric power plants. Thus, the objective of this study was to evaluate the reproductive activity of the large migratory Amazonian catfish of the genus Brachyplatystoma after the construction of two hydroelectric plants (Santo Antônio and Jirau) on the Madeira River, Brazilian Amazonian; and, to verify, by generalized linear models adjustment, if the reservoir of Santo Antônio dam has acted as a barrier to the descending movements of ichthyoplankton. A construção de empreendimentos hidrelétricos representa uma das maiores ameaças à diversidade íctica em todo o mundo, em especial, nos rios tropicais, em que muitas espécies de alto valor comercial migram centenas de quilômetros em resposta aos pulsos de inundação. A interrupção da conectividade fluvial, ocasionada pelo barramento, compromete a conexão entre habitat que são indispensáveis para o ciclo de vida destas espécies, podendo afetar negativamente tanto sua reprodução, quanto recrutamento. Neste contexto, a bacia Amazônica, que contém a maior diversidade de peixes de água doce do planeta, está sendo fortemente ameaçada devido à crescente construção de usinas hidrelétricas. Assim, neste estudo, por meio de dados de ovos e larvas de peixes, avaliou-se a atividade reprodutiva das espécies dos grandes bagres migradores amazônicos do gênero Brachyplatystoma após a instalação de duas usinas hidrelétricas (Santo Antônio e Jirau) no rio Madeira, Amazônia brasileira; e verificou-se, por meio de ajustes de modelos lineares generalizados, se o reservatório da usina hidrelétrica Santo Antônio tem atuado como barreira para os movimentos descendentes do ictioplâncton. 95 f

In the present work, we have considered the vulnerability of some rare tree species to human disturbances in a high biodiversity tropical region. In this context, we aimed to evaluate the combined effect of deforestation and artificial flooding of the large Jirau hydroelectric reservoir on potential distribution areas of 13 locally rare tree species in the southwestern Brazilian Amazon. We performed species distribution modeling (SDM) by using the environmental distance algorithm. Based on these models, we found new sites and subsequently applied rapid ecological assessment to collect further species occurrence data. Additional SDMs were carried out using MaxEnt to determine the potential distribution areas of these rare species. We found that artificial flooding and deforestation caused combined losses of potential distribution areas of rare tree species between 8 and 39% of the total area. The most vulnerable species were Semaphyllanthe megistocaula (K. Krause) L. Andersson (Rubiaceae) (39%), Chrysophyllum colombianum (Aubrev.) T.D. Penn. (Sapotaceae) (34%), Lacunaria jenmanii (Oliv.) Ducke (Quiinaceae) (32%), Brosimum parinarioides Ducke (Moraceae) (32%) and Xylopia benthamii R.E. Fr. (Annonaceae) (30%). These results indicate an additive effect of human disturbances such that artificial flooding, when combined with deforestation, has an overall effect by orders of magnitude. SDMs can be effectively used as a predictive tool in the assessment of human impacts on rare tree species in tropical forests. The results also showed different vulnerability among the rare species, and these results may indicate that some species are more seriously threatened by the extreme loss of potential distribution areas.

Biological collections preserve the biodiversity of a nation. The fish collection of the Universidade Federal de Rondônia, recently established, contains about 41% of freshwater fish species known to occur in Brazil, and 24% of South America. The biological material is distributed into 1,067 species, 21,963 lots and 149,192 specimens, gathered during five years of work. From this collection, 99% of the lots have georeferenced location, and 94% of the species were sampled in the Madeira River basin, the largest tributary in flow, drainage area and sediment discharge of the Amazonas River basin. Among the 1,008 species collected in the Madeira River basin, 80% were reviewed by Brazilian, North American and French experts, and represents the highest richness among tributaries of the Amazonas River and other rivers worldwide. Fish collection from the Madeira River basin deposited in the ichthyological collection of the Universidade Federal de Rondônia accounts for about 75% of the lots and specimens of fish from that basin available for study in collections worldwide. Biological collections preserve the biodiversity of a nation. The fish collection of the Universidade Federal de Rondônia, recently established, contains about 41% of freshwater fish species known to occur in Brazil, and 24% of South America. The biological material is distributed into 1,067 species, 21,963 lots and 149,192 specimens, gathered during five years of work. From this collection, 99% of the lots have georeferenced location, and 94% of the species were sampled in the Madeira River basin, the largest tributary in flow, drainage area and sediment discharge of the Amazonas River basin. Among the 1,008 species collected in the Madeira River basin, 80% were reviewed by Brazilian, North American and French experts, and represents the highest richness among tributaries of the Amazonas River and other rivers worldwide. Fish collection from the Madeira River basin deposited in the ichthyological collection of the Universidade Federal de Rondônia accounts for about 75% of the lots and specimens of fish from that basin available for study in collections worldwide.