Environmental demands for sustainable regulation schemes in the humid tropics

Water is one of the most important natural resources in many countries of the humid tropics. It supports many socio-economic activities and provides a renewable energy source for economic development. Sustainability of water projects includes maintenance of biodiversity. Consideration of environmental demands in the basins is an essential component in regulation schemes. This study utilized an Expert Panel Approach to select indicator species for a sustainable runoff in a tropical environment of Costa Rica and to identify their environmental demands. A ranked list of indicator species, chosen based on their sensitivity to changes in river flow caused by regulation, was suggested by experts on tropical flora and fauna at the first expert panel. The second expert panel defined environmental demands of the proposed indicator species in terms of water depth, stream velocity and substrate type. The information obtained provides the necessary background for evaluation of the impact of different regulation schemes on the aquatic environment.