Historical documents were analyzed to reconstruct the effect of human activities on the insular territories of Aysen from the XVI to XIX centuries. The results show that the impact of anthropogenic activities on the environment reached its peak during the second half of the XIX century, which was marked by a significant degradation of local ecosystems due to the commercial hunting of pinnipeds and the exploitation of Guaitecas' cypress. In comparison, alteration of the natural landscape by the activities of aboriginals and those associated with the Spanish colonization of Chiloe, was mild to moderate. The colonization process, however, strongly decimated the insular cultures, which resulted in the disappearance of the indigenous populations that occupied the Aysen archipelagos. It was also observed that the biogeography and physiography of the region limited the impact of human activities on the environment, hence contributing to the preservation of the ecological landscape of the islands.