The ecological roles of humans in marine communities have been poorly studied. Humans have special characteristics, such as culture, and are perceived as complex ecological actors. Observations and experiments conducted in coastal (rocky intertidal and nearshore) 'no-take' areas or reserves in Chile and around the world have permitted a better understanding of the role played by humans as top predators and the resulting trophic-cascade effects along: the food-webs. These studies have revealed an urgent need to incorporate humans into ecological studies and have helped to promote links between ecology and social sciences.