Large reservoirs are an increasingly common feature across tropical landscapes because of their importance for water supply, flood control and hydropower, but their ecological conditions are infrequently evaluated. Our objective was to assess the range of disturbances for two large tropical reservoirs and their influences on benthic macroinvertebrates. We tested three hypotheses: i) a wide variation in the level of environmental disturbance can be observed among sites in the reservoirs; ii) the two reservoirs would exhibit a different degree of disturbance level; and iii) the magnitude of disturbance would influence the structure and composition of benthic assemblages. For each reservoir, we assessed land use (macroscale), physical habitat structure (mesoscale), and water quality (microscale). We sampled 40 sites in the littoral zones of both Três Marias and São Simão Reservoirs (Minas Gerais, Brazil). At the macroscale, we measured cover percentages of land use categories in buffer areas at each site, where each buffer was a circular arc of 250 m. At the mesoscale, we assessed the presence of human disturbances in the riparian and drawdown zones at the local (site) scale. At the microscale, we assessed water quality at each macroinvertebrate sampling station using the Micro Disturbance Index (MDI). To evaluate anthropogenic disturbance of each site, we calculated an integrated disturbance index (IDI) from a buffer disturbance index (BDI) and a local disturbance index (LDI). For each site, we calculated richness and abundance of benthic macroinvertebrates, Chironomidae genera richness, abundance and percent Chironomidae individuals, abundance and percent EPT individuals, richness and percent EPT taxa, abundance and percent resistant individuals, and abundance and percent non-native individuals. We also evaluated the influence of disturbance on benthic macroinvertebrate assemblages at the entire-reservoir scale. The BDI, LDI and IDI had significantly greater average scores at São Simão than at Três Marias Reservoir. The significantly greater differences in IDI scores for São Simão Reservoir were reflected in 10 of the 13 Ekman-Birge dredge biotic metrics and in 5 of 13 of the kick-net biotic metrics. We also observed clear ranges of disturbances within both reservoirs at macro (BDI) and mesoscales (LDI) and in water quality, but an insignificant range in MDI results. However, we found no significant relationship between the benthic macroinvertebrate metrics and the BDI, LDI, and IDI among sites within a single reservoir. Hence, we believe that benthic macroinvertebrate distributions in those reservoirs were influenced by other factors or that reservoir macroinvertebrates (dominated by chironomids) were poor indicators of disturbance at the site scale.

No abstract

This book is dedicated to the memory of our friend Volney Vono. We miss him, his funny stories, and his ecological knowledges.

Gastropod molluscs have potential for bioaccumulation of the organotin compounds (OTs) as tributyltin (TBT) and/or triphenyltin (TPT), used in antifouling paints applied to the hulls of ships to prevent biofouling. In gastropods, TBT may act as endocrine disruptors, and to induce imposex, impairing their reproductive capacity. The present study aimed to verify the occurrence of malformations, such as biphalic and triphalic penis in males and females with imposex in Leucozonia nassa and L. ocellata collected in Espírito Santo Bay between the years 2007 and 2011. During this period, 94.8% of female L. nassa and 24.5% of female L. ocellata exhibited imposex and 10 animals presented malformations. For L. nassa, malformations were found in seven females and one male, and for L. ocellata in two males. Most females with malformations presented VDSI stage ≥4 and these results indicate high levels of TBT contamination in the Espirito Santo Bay.

Nas últimas décadas a preocupação com os indesejáveis resultados dos efeitos de atividades humanas sobre o meio ambiente aumentou consideravelmente. Toleram-se cada vez menos os problemas ambientais que interferem na qualidade de vida, especialmente a poluição dos corpos d'água, devido ao lançamento e acúmulo de efluentes industriais e esgotos domésticos sem tratamento. Os rios que banham metrópoles, a exemplo de São Paulo e Belo Horizonte, estão praticamente mortos: servem apenas como um canal por onde escoa todo o esgoto produzido pelas atividades cotidianas dos indivíduos da população urbana.O estabelecimento da Política Nacional de Recursos Hídricos, instituída pela lei nº 9.433 de 8 de janeiro de 1997, é um marco institucional no país. Incorpora princípios e normas para a gestão de recursos hídricos adotando as bacias hidrográficas como regiões naturais de abrangência e como unidade de gestão e planejamento. A água destas bacias é considerada um bem destinado ao consumo humano, de uso múltiplo e de domínio público, além de ser um recurso natural limitado e dotado de valor econômico (Tucci 2002).Reconhece-la como recurso natural dotado de valor econômico é inevitável (Costanza et al. 1997) e a cobrança pelo seu uso econômico, começando pelos grandes usuários, visa incentivar que a utilização da água o seja de modo racional. De fato, é necessário garantir que os bens ambientais sejam valorizados monetariamente, em especial naquelas áreas sob a influência de empreendimentos potencialmente impactantes, porque nestes casos as reparações sociais ou ambientais não atendem satisfatoriamente a todos os interesses das populações humanas afetadas (Brasil 2005). É interessante registrar que a lei agrícola 8.171/1991, precedendo à lei 9433/97, no seu artigo 20 diz:"As bacias hidrográficas constituem-se em unidades básicas de planejamento do uso, da conservação e da recuperação dos recursos naturais. " (Brasil 1991) No entanto, as leis brasileiras reconhecem a qualidade da água tendo em vista apenas o seu grau de potabilidade e balneabilidade não considerando a integridade ecológica dos ecossistemas aquáticos que constituem as bacias hidrográficas. Por isso, a classificação dos corpos d'água é realizada por meio do estabelecimento de padrões de qualidade determinados pela ocorrência de variáveis-críticas que afetam decisivamente essa qualidade (p. ex. quantidade de matéria orgânica como DBO ou DQO). Estas podem ser de origem antrópica (esgotos domésticos) ou natural (macrófitas aquáticas em decomposição). A utilização da bacia hidrográfica como unidade territorial, para a qual a gestão de recursos hídricos deve ser dirigida, deve-se a uma abordagem ambiental integrada, necessária para que se avalie adequadamente os impactos que podem ocorrer devido à implantação de empreendimentos que têm alto potencial impactante, tal qual a instalação de hidroelétricas. Esta abordagem integrada, realizada em fase anterior à concessão do licenciamento ambiental, leva em conta os efeitos cumulativos e sinérgicos que tais empreendiment...

This book is dedicated to the memory of our friend Volney Vono. We miss him, his funny stories, and his ecological knowledges.

This study represents the first use of Leucozonia nassa (Mollusca-Gastropoda) in a program of long-term monitoring. Specimens of L. nassa were collected between 2006 and 2014 and analyzed for the occurrence of imposex in two areas in Southeastern Brazil, one control area and another characterized by the presence of many ports and marinas. Imposex was evaluated in nine sites based on the percentage of females exhibiting imposex (I%), relative penis length index and vas deferens sequence index, classical indices to evaluate tributyltin (TBT) impacts. Moreover, this study uses for the first time in a tropical environment the ecological quality ratio (EQR), an approach to verify the imposex levels as an indicator of the impact by organotin compounds according to the EU Water Framework Directive. The results confirm the occurrence of high levels of imposex in L. nassa with all the indices evaluated. Furthermore, the results also indicate that, despite the international ban, antifouling paints based on TBT are still possibly used in Brazil. In addition, this study shows that L. nassa has the characteristics that make it a suitable bioindicator to monitor TBT pollution, and that the use of the EQR may create important data regarding this problem.

This book is dedicated to the memory of our friend Volney Vono. We miss him, his funny stories, and his ecological knowledges.