Reservoirs and human well being: new challenges for evaluating impacts and benefits in the neotropics.

As in many other continents, neotropical ecosystems are impacted by the construction of reservoirs. These artificial ecosystems change considerably the natural terrestrial and aquatic ecosystems and their biodiversity. The multiple uses of reservoirs promote benefits for the human beings in terms of economic development, income, jobs and employment. Services of reservoirs are important assets for the regional ecosystem. Evaluation of ecosystem services produced by artificial reservoirs, are new challenges to the understanding of the cost/benefit relationships of reservoir construction in the neotropics. Regulating and other services promoted by reservoirs lead to new trends for 'green technology' and the implementation of ecohydrological and ecotechnological developments. This approach can be utilized with better success as a substitute for the usual impact/benefit evaluation of the reservoirs. Better and diversified services can be achieved with 'green technology' applied to the construction.