The aim of this study was to understand how a stream ecosystem that flows from its fountainhead to its mouth inside a city, changes from a water resource to a point pollution source. A multidisciplinary descriptive approach was adopted, including the short-term temporal and spatial determination of physical, chemical, biological and ecotoxicological variables. Results showed that water quality rapidly decreases with increasing urbanization, leading the system to acquire raw sewage attributes even in the first hundred meters after the fountainheads. Despite the tidal circulation near the stream mouth being restricted by shallowness, some improvement of the water quality was detected in this area. The multidisciplinary evaluation showed to be useful for obtaining a more realistic understanding of the stream degradation process, and to forecast restoration and mitigation measures.

Increasing anthropogenic influence on lotic environments as a result of civilisation has captured public interest because of the consequent problems associated with deterioration of water quality. Various biological monitoring methods that provide a direct measure of ecological integrity by using the response of biota to environmental changes have been developed to monitor the ecological status of lotic environments. Diatoms have been used extensively in this regard and this review attempts to summarise the basic concepts associated with biological monitoring using benthic diatoms. Where possible, examples from work carried out in Brazil are used.Keywords: biological monitoring, lotic environment, benthic diatoms. Biomonitoramento dos ecossistemas lóticos: o papel das diatomáceasResumo O aumento da influência antropogênica sobre ambientes lóticos como resultado da civilização conquistou o interesse público por causa de problemas relacionados com a consequente deterioração da qualidade da água. Vários métodos de biomonitoramento que fornecem uma medida direta da integridade ecológica usando a resposta da biota a alterações ambientais têm sido desenvolvidos para monitorar o estado ecológico de ecossistemas lóticos. Diatomáceas têm sido amplamente utilizadas e esta revisão tenta resumir os conceitos básicos associados ao monitoramento biológico utilizando diatomáceas bentônicas. Sempre que possível, exemplos de trabalhos realizados no Brasil serão utilizados.Palavras-chave: biomonitoramento, ecossistemas lóticos, diatomáceas bentônicas.

The aim of this study was to identify and make an initial accounting of the ecosystem services of the hydroelectric power generation plant, UHE Carlos Botelho (Itirapina Municipality, São Paulo State, Brazil), and its most extensive wetlands -total of 2,640 ha -and also identify the drivers of change of these services. Twenty (20) ecosystem services were identified and the estimated quantitative total value obtained was USD 120,445,657.87. year -1 or USD 45,623.35 ha -1 .year -1 . Investments on restoration of spatial heterogeneity along Tietê-Jacaré hydrographic basin and new technologies for regional economic activities must maintain ecological functions as well as increase marginal values of ecosystem services and the potential annual economic return of ecological functions.Keywords: neotropical reservoirs, ecosystem services, hydrographic basin management, cost-benefit analysis, wetlands, drivers. Serviços ecossistêmicos do reservatório da UHE Carlos Botelho (Lobo-Broa): uma nova abordagem para o gerenciamento e planejamento dos múltiplos usos de represas ResumoEste estudo teve como objetivo identificar e valorar os serviços ecossistêmicos da UHE Carlos Botelho (Itirapina, Estado de São Paulo, Brasil) e suas áreas alagadas mais extensas e também identificar as forçantes de alterações nestes serviços. Vinte (20) serviços ecossistêmicos foram identificados e o valor quantitativo total estimado obtido resultou em USD 120.445.657,87. ano -1 ou USD 45.623,35 ha -1 .ano -1 . Investimentos na restauração da heterogeneidade espacial da bacia hidrográfica do Tietê-Jacaré e em novas tecnologias para as atividades econômicas regionais devem contribuir para a manutenção das funções ecológicas e para o aumento dos valores marginais e do valor potencial anual de retorno dos serviços ecossistêmicos.Palavras-chave: reservatórios neotropicais, serviços ecossistêmicos, gerenciamento da bacia hidrográfica, análise custo-benefício, áreas alagadas, forçantes.

One of the most important factors that impacts aquatic biodiversity is global warming which is one of the consequences of global changes. A change in 2°C or 3°C in the surface temperature of lakes, reservoirs or rivers stimulates the growth and dominance of cyanobacteria. Among these, the presence of Cylindrospermopsis raciborskii is becoming extremely common.Accordingly to Paerl and Huisman (2008), this species produces toxins that affect fishes, zooplankton, other components of the aquatic biota, and even humans. The appearance of cyanobacterial blooms connected with global warming has been registered by several authors over the last 10 years.A sudden invasion of Cylindrospermopsis raciborskii at UHE Carlos Botelho reservoir (Lobo/ Broa in São Paulo, Brazil, was described by Tundisi et al. (2015) as a consequence of interactions of climatological and hydrological changes connected with the dry period that occurred in the Southeast of Brazil (São Paulo) in 2013-2014.The problem is even more serious in the tropical regions where uncontrolled eutrophication can enhance the growth and development of fresh water blooms.Economic and human health impacts should be quantified in this context. The impact on biodiversity occurs at several levels of the food chain and should also be quantified. The Brazilian Journal of Biology is open to qualified papers on this subject.