The Cagarras Archipelago consists in a postcard of Rio de Janeiro, visible from its entire coastline. In December,2011 many prehistoric lithic artifacts, dozens of fragments of pottery have been discovered at Ilha Redonda,besides a remaining specimen of sweet potato (Ipomoea batatas), with evidence of having been introduced in the pre-colonial period. This paper aims to examine the potential use of resources of the landscape of the archipelago by pre-colonial populations from the material culture found and the characteristics of the ecosystem. Besides presenting a priceless biological heritage, it consists also in a remarkable source of information about the past of human history in the region.