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In this essay the authors discuss the integration of ecohydrology, water management practice and watershed economy as fundamentals for the new water governance paradigm. The “nature's software” – ecohydrological processes and resulting ecosystem services should be coupled with ‘human hardware’ in the form of civil and hydrotechnical engineering, ecological engineering and ecosystem biotechnologies in a template of hydrosocial cycle adapting to the global changes. The competent and adequate water governance requires as a priority water security for the human population and for ecosystem functioning. Three case studies from Brazil are presented in order to illustrate how this integration has been realized so far, and the benefits for ecosystems and economy are presented. The case studies are: the Lobo Broa reservoir project, the sustainable management of the Pantanal wetland, and the São Francisco River Basin Management Plan. The practical results of these conceptual approaches are discussed and future research needs are identified. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the current study was to assess the applicability of the Pampean Diatom Index (the PDI) to natural communities other than epipelic diatom communities as well as those growing on artificial substrates in Monjolinho River and its tributaries, São Carlos-SP, Brazil. Benthic diatoms and water quality sampling was done at 10 sites during summer base flow period (2008 and 2009). The PDI scores were calculated based on epilithic, epiphytic, epipsammic and epipelic diatom communities as well as those growing on bricks and glass substrates. Pearson correlation was used to determine the relationship between the PDI scores from different substrates sampled and measured physical and chemical water quality data. Two-way ANOVA was used to compare these correlation values among substrates. The PDI scores based on all the substrates showed significant correlations with physical and chemical variables. Insignificant differences in the PDI scores based on different natural substrates were recorded, with all substrates classifying the sites into to roughly the same categories. In the light of these results, the PDI can be applied to communities other than epipelic, and is applicable to the study area. The choice of substrate sampled may not affect accuracy of the PDI-based water quality assessment. [Copyright &y& Elsevier]

Benthic diatoms are important indicators of ecological conditions in lotic systems. The objective of this study was to elucidate the confounding effects of eutrophication, organic pollution and ionic strength and conductivity on benthic diatom communities. Benthic diatoms and water quality sampling was done at 10 sites during summer base flow period (2008 and 2009). Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to determine environmental gradients along which species vary with respect to ionic strength and conductivity and other environmental variables. Using variance partitioning, we assessed the individual importance of a set of environmental variables (eutrophication and organic pollution) versus ionic strength and conductivity on diatom community structure. The effects of ionic strength and conductivity and organic pollution, eutrophication and other environmental variables were integrated into overall resultant benthic diatom communities. Through partial CCA, we partitioned the variance in diatom data between two sets of exploratory variables, i.e. ionic strength and conductivity (26.9%); other variables, particularly eutrophication and organic pollution (23.0%); shared variance (11.3%) and unexplained variance (38.8%). Due to the interaction of the effects of ionic strength and conductivity and other variables in this study, laboratory experiments must be performed to confirm the observed effects of ionic strength and conductivity. [ABSTRACT FROM AUTHOR]

Among the zooplankton groups the Calanoida copepods present a high degree of endemism with a very restricted geographic distribution. This endemism can be a response to the sensibility of these organisms to changes in chemical and physical factors such as pH, conductivity and ionic ratios. Studies on the composition and distribution of the Calanoida species in 21 reservoirs of São Paulo State, carried out from 1979 onwards, and the studies on Barra Bonita Reservoir show a complete change in species composition including the appearance of a new species. Species which were frequent such as Notodiaptomus conifer in the majority of the reservoirs of the Middle Tiete and Paranapanema River basins, disappeared completely, being substituted by other species. At the Barra Bonita Reservoir, species such as Argyrodiaptomus furcatus, and Scolodiaptomus corderoi, which are typical of waters of low conductivity (up to 100 μS cm-1 ) and pH near 7.0, were substituted by species of Notodiaptomus iheringi and N. cearensis dwellers in waters of conductivity much higher than 100 μS cm-1 (up to 500 μS cm-1) and lower pH than 7.0. Structural changes in the zooplankton community can be the first step towards large scale changes in reservoir functions as a consequence of eutrophication and toxicity. [ABSTRACT FROM AUTHOR]

The construction of large reservoirs in South America and particularly in Brazil has intensified within the last 50 years. Built up primarily for hydroelectricity production, these artificial ecosystems now serve purposes such as: water storage for public use; fisheries and aquaculture; recreation; tourism, and irrigation. These artificial ecosystems were also built up with the purpose of enhancing the regional development. These activities produce multiple impacts among which are eutrophication, a serious problems with various ecological, economic, and social consequences. Basic studies on reservoirs have identified their main ecological characteristics and described some of their fundamental mechanisms of functioning. This information cover: factors involved in reservoir complexity, such as spatial scale, vertical and horizontal heterogeneity, temporal variation at several time scales and, in some cases, watershed/reservoir relationships, and the impact of non-point and point sources of nutrients. Numerous studies have been dedicated to describing aquatic biota, its relationship with environmental factors, and the impacts of degradation/pollution/ eutrophication on biodiversity. Research priorities have been established mainly by limnologists in response to needs identified by environmental impact assessment. Due to the pressure of multiple uses, population growth, and economic factors, aquatic scientists now face a number of questions being posed by managers and engineers. These questions relate to a wide range of practical problems, the solutions to which depend on accumulated data related to the structural complexities and function mechanisms previously referred to. These problems can be divided into three main groups: (i) eutrophication processes and their characteristics, and water quality control; (ii) impact of fisheries, aquaculture, and exotic species introduction on the biota and the water quality; (iii) sustainable development of reservoirs and optimization management of their multiple uses. Predictive capabilities required in the face of these problems should be based on modeling development and intensive use of data-bases resulting from long-term studies on reservoirs. The predictions thus made possible would involve economic factors and the costs of recovery of eutrophic reservoirs. The experience of reservoir research and management in South America and in Brazil is, probably part of a world wide tendency on reservoir research and development with the aim to optimize multiple uses. Based on the cooperation of limnologists and engineers, ecosystem management models must eventually be applied at the watershed / reservoir level, where demands on the part of managers and decision makers will certainly promote a predictive, integrated, and adaptive approach, based on fundamental research. [ABSTRACT FROM AUTHOR]