sentences:  Arrangements between the Aymara people and the rest of the management committee for the park have helped to ensure excessive planning and local participation in decisions is taking place, but admittedly plans are not always perfect.Even when using the most optimistic of scenarios, SERNAP concedes that a fair number of indigenous people will have to leave this region in order to assure a minimum livelihood.In situations like these, every cost and benefit of ecotourism must be carefully weighed.